xref: /freebsd/contrib/llvm-project/clang/lib/CodeGen/CGExprScalar.cpp (revision e1e636193db45630c7881246d25902e57c43d24e)
1 //===--- CGExprScalar.cpp - Emit LLVM Code for Scalar Exprs ---------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This contains code to emit Expr nodes with scalar LLVM types as LLVM code.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #include "CGCXXABI.h"
14 #include "CGCleanup.h"
15 #include "CGDebugInfo.h"
16 #include "CGObjCRuntime.h"
17 #include "CGOpenMPRuntime.h"
18 #include "CodeGenFunction.h"
19 #include "CodeGenModule.h"
20 #include "ConstantEmitter.h"
21 #include "TargetInfo.h"
22 #include "clang/AST/ASTContext.h"
23 #include "clang/AST/Attr.h"
24 #include "clang/AST/DeclObjC.h"
25 #include "clang/AST/Expr.h"
26 #include "clang/AST/RecordLayout.h"
27 #include "clang/AST/StmtVisitor.h"
28 #include "clang/Basic/CodeGenOptions.h"
29 #include "clang/Basic/TargetInfo.h"
30 #include "llvm/ADT/APFixedPoint.h"
31 #include "llvm/IR/CFG.h"
32 #include "llvm/IR/Constants.h"
33 #include "llvm/IR/DataLayout.h"
34 #include "llvm/IR/DerivedTypes.h"
35 #include "llvm/IR/FixedPointBuilder.h"
36 #include "llvm/IR/Function.h"
37 #include "llvm/IR/GetElementPtrTypeIterator.h"
38 #include "llvm/IR/GlobalVariable.h"
39 #include "llvm/IR/Intrinsics.h"
40 #include "llvm/IR/IntrinsicsPowerPC.h"
41 #include "llvm/IR/MatrixBuilder.h"
42 #include "llvm/IR/Module.h"
43 #include "llvm/Support/TypeSize.h"
44 #include <cstdarg>
45 #include <optional>
46 
47 using namespace clang;
48 using namespace CodeGen;
49 using llvm::Value;
50 
51 //===----------------------------------------------------------------------===//
52 //                         Scalar Expression Emitter
53 //===----------------------------------------------------------------------===//
54 
55 namespace {
56 
57 /// Determine whether the given binary operation may overflow.
58 /// Sets \p Result to the value of the operation for BO_Add, BO_Sub, BO_Mul,
59 /// and signed BO_{Div,Rem}. For these opcodes, and for unsigned BO_{Div,Rem},
60 /// the returned overflow check is precise. The returned value is 'true' for
61 /// all other opcodes, to be conservative.
62 bool mayHaveIntegerOverflow(llvm::ConstantInt *LHS, llvm::ConstantInt *RHS,
63                              BinaryOperator::Opcode Opcode, bool Signed,
64                              llvm::APInt &Result) {
65   // Assume overflow is possible, unless we can prove otherwise.
66   bool Overflow = true;
67   const auto &LHSAP = LHS->getValue();
68   const auto &RHSAP = RHS->getValue();
69   if (Opcode == BO_Add) {
70     Result = Signed ? LHSAP.sadd_ov(RHSAP, Overflow)
71                     : LHSAP.uadd_ov(RHSAP, Overflow);
72   } else if (Opcode == BO_Sub) {
73     Result = Signed ? LHSAP.ssub_ov(RHSAP, Overflow)
74                     : LHSAP.usub_ov(RHSAP, Overflow);
75   } else if (Opcode == BO_Mul) {
76     Result = Signed ? LHSAP.smul_ov(RHSAP, Overflow)
77                     : LHSAP.umul_ov(RHSAP, Overflow);
78   } else if (Opcode == BO_Div || Opcode == BO_Rem) {
79     if (Signed && !RHS->isZero())
80       Result = LHSAP.sdiv_ov(RHSAP, Overflow);
81     else
82       return false;
83   }
84   return Overflow;
85 }
86 
87 struct BinOpInfo {
88   Value *LHS;
89   Value *RHS;
90   QualType Ty;  // Computation Type.
91   BinaryOperator::Opcode Opcode; // Opcode of BinOp to perform
92   FPOptions FPFeatures;
93   const Expr *E;      // Entire expr, for error unsupported.  May not be binop.
94 
95   /// Check if the binop can result in integer overflow.
96   bool mayHaveIntegerOverflow() const {
97     // Without constant input, we can't rule out overflow.
98     auto *LHSCI = dyn_cast<llvm::ConstantInt>(LHS);
99     auto *RHSCI = dyn_cast<llvm::ConstantInt>(RHS);
100     if (!LHSCI || !RHSCI)
101       return true;
102 
103     llvm::APInt Result;
104     return ::mayHaveIntegerOverflow(
105         LHSCI, RHSCI, Opcode, Ty->hasSignedIntegerRepresentation(), Result);
106   }
107 
108   /// Check if the binop computes a division or a remainder.
109   bool isDivremOp() const {
110     return Opcode == BO_Div || Opcode == BO_Rem || Opcode == BO_DivAssign ||
111            Opcode == BO_RemAssign;
112   }
113 
114   /// Check if the binop can result in an integer division by zero.
115   bool mayHaveIntegerDivisionByZero() const {
116     if (isDivremOp())
117       if (auto *CI = dyn_cast<llvm::ConstantInt>(RHS))
118         return CI->isZero();
119     return true;
120   }
121 
122   /// Check if the binop can result in a float division by zero.
123   bool mayHaveFloatDivisionByZero() const {
124     if (isDivremOp())
125       if (auto *CFP = dyn_cast<llvm::ConstantFP>(RHS))
126         return CFP->isZero();
127     return true;
128   }
129 
130   /// Check if at least one operand is a fixed point type. In such cases, this
131   /// operation did not follow usual arithmetic conversion and both operands
132   /// might not be of the same type.
133   bool isFixedPointOp() const {
134     // We cannot simply check the result type since comparison operations return
135     // an int.
136     if (const auto *BinOp = dyn_cast<BinaryOperator>(E)) {
137       QualType LHSType = BinOp->getLHS()->getType();
138       QualType RHSType = BinOp->getRHS()->getType();
139       return LHSType->isFixedPointType() || RHSType->isFixedPointType();
140     }
141     if (const auto *UnOp = dyn_cast<UnaryOperator>(E))
142       return UnOp->getSubExpr()->getType()->isFixedPointType();
143     return false;
144   }
145 };
146 
147 static bool MustVisitNullValue(const Expr *E) {
148   // If a null pointer expression's type is the C++0x nullptr_t, then
149   // it's not necessarily a simple constant and it must be evaluated
150   // for its potential side effects.
151   return E->getType()->isNullPtrType();
152 }
153 
154 /// If \p E is a widened promoted integer, get its base (unpromoted) type.
155 static std::optional<QualType> getUnwidenedIntegerType(const ASTContext &Ctx,
156                                                        const Expr *E) {
157   const Expr *Base = E->IgnoreImpCasts();
158   if (E == Base)
159     return std::nullopt;
160 
161   QualType BaseTy = Base->getType();
162   if (!Ctx.isPromotableIntegerType(BaseTy) ||
163       Ctx.getTypeSize(BaseTy) >= Ctx.getTypeSize(E->getType()))
164     return std::nullopt;
165 
166   return BaseTy;
167 }
168 
169 /// Check if \p E is a widened promoted integer.
170 static bool IsWidenedIntegerOp(const ASTContext &Ctx, const Expr *E) {
171   return getUnwidenedIntegerType(Ctx, E).has_value();
172 }
173 
174 /// Check if we can skip the overflow check for \p Op.
175 static bool CanElideOverflowCheck(const ASTContext &Ctx, const BinOpInfo &Op) {
176   assert((isa<UnaryOperator>(Op.E) || isa<BinaryOperator>(Op.E)) &&
177          "Expected a unary or binary operator");
178 
179   // If the binop has constant inputs and we can prove there is no overflow,
180   // we can elide the overflow check.
181   if (!Op.mayHaveIntegerOverflow())
182     return true;
183 
184   // If a unary op has a widened operand, the op cannot overflow.
185   if (const auto *UO = dyn_cast<UnaryOperator>(Op.E))
186     return !UO->canOverflow();
187 
188   // We usually don't need overflow checks for binops with widened operands.
189   // Multiplication with promoted unsigned operands is a special case.
190   const auto *BO = cast<BinaryOperator>(Op.E);
191   auto OptionalLHSTy = getUnwidenedIntegerType(Ctx, BO->getLHS());
192   if (!OptionalLHSTy)
193     return false;
194 
195   auto OptionalRHSTy = getUnwidenedIntegerType(Ctx, BO->getRHS());
196   if (!OptionalRHSTy)
197     return false;
198 
199   QualType LHSTy = *OptionalLHSTy;
200   QualType RHSTy = *OptionalRHSTy;
201 
202   // This is the simple case: binops without unsigned multiplication, and with
203   // widened operands. No overflow check is needed here.
204   if ((Op.Opcode != BO_Mul && Op.Opcode != BO_MulAssign) ||
205       !LHSTy->isUnsignedIntegerType() || !RHSTy->isUnsignedIntegerType())
206     return true;
207 
208   // For unsigned multiplication the overflow check can be elided if either one
209   // of the unpromoted types are less than half the size of the promoted type.
210   unsigned PromotedSize = Ctx.getTypeSize(Op.E->getType());
211   return (2 * Ctx.getTypeSize(LHSTy)) < PromotedSize ||
212          (2 * Ctx.getTypeSize(RHSTy)) < PromotedSize;
213 }
214 
215 class ScalarExprEmitter
216   : public StmtVisitor<ScalarExprEmitter, Value*> {
217   CodeGenFunction &CGF;
218   CGBuilderTy &Builder;
219   bool IgnoreResultAssign;
220   llvm::LLVMContext &VMContext;
221 public:
222 
223   ScalarExprEmitter(CodeGenFunction &cgf, bool ira=false)
224     : CGF(cgf), Builder(CGF.Builder), IgnoreResultAssign(ira),
225       VMContext(cgf.getLLVMContext()) {
226   }
227 
228   //===--------------------------------------------------------------------===//
229   //                               Utilities
230   //===--------------------------------------------------------------------===//
231 
232   bool TestAndClearIgnoreResultAssign() {
233     bool I = IgnoreResultAssign;
234     IgnoreResultAssign = false;
235     return I;
236   }
237 
238   llvm::Type *ConvertType(QualType T) { return CGF.ConvertType(T); }
239   LValue EmitLValue(const Expr *E) { return CGF.EmitLValue(E); }
240   LValue EmitCheckedLValue(const Expr *E, CodeGenFunction::TypeCheckKind TCK) {
241     return CGF.EmitCheckedLValue(E, TCK);
242   }
243 
244   void EmitBinOpCheck(ArrayRef<std::pair<Value *, SanitizerMask>> Checks,
245                       const BinOpInfo &Info);
246 
247   Value *EmitLoadOfLValue(LValue LV, SourceLocation Loc) {
248     return CGF.EmitLoadOfLValue(LV, Loc).getScalarVal();
249   }
250 
251   void EmitLValueAlignmentAssumption(const Expr *E, Value *V) {
252     const AlignValueAttr *AVAttr = nullptr;
253     if (const auto *DRE = dyn_cast<DeclRefExpr>(E)) {
254       const ValueDecl *VD = DRE->getDecl();
255 
256       if (VD->getType()->isReferenceType()) {
257         if (const auto *TTy =
258                 VD->getType().getNonReferenceType()->getAs<TypedefType>())
259           AVAttr = TTy->getDecl()->getAttr<AlignValueAttr>();
260       } else {
261         // Assumptions for function parameters are emitted at the start of the
262         // function, so there is no need to repeat that here,
263         // unless the alignment-assumption sanitizer is enabled,
264         // then we prefer the assumption over alignment attribute
265         // on IR function param.
266         if (isa<ParmVarDecl>(VD) && !CGF.SanOpts.has(SanitizerKind::Alignment))
267           return;
268 
269         AVAttr = VD->getAttr<AlignValueAttr>();
270       }
271     }
272 
273     if (!AVAttr)
274       if (const auto *TTy = E->getType()->getAs<TypedefType>())
275         AVAttr = TTy->getDecl()->getAttr<AlignValueAttr>();
276 
277     if (!AVAttr)
278       return;
279 
280     Value *AlignmentValue = CGF.EmitScalarExpr(AVAttr->getAlignment());
281     llvm::ConstantInt *AlignmentCI = cast<llvm::ConstantInt>(AlignmentValue);
282     CGF.emitAlignmentAssumption(V, E, AVAttr->getLocation(), AlignmentCI);
283   }
284 
285   /// EmitLoadOfLValue - Given an expression with complex type that represents a
286   /// value l-value, this method emits the address of the l-value, then loads
287   /// and returns the result.
288   Value *EmitLoadOfLValue(const Expr *E) {
289     Value *V = EmitLoadOfLValue(EmitCheckedLValue(E, CodeGenFunction::TCK_Load),
290                                 E->getExprLoc());
291 
292     EmitLValueAlignmentAssumption(E, V);
293     return V;
294   }
295 
296   /// EmitConversionToBool - Convert the specified expression value to a
297   /// boolean (i1) truth value.  This is equivalent to "Val != 0".
298   Value *EmitConversionToBool(Value *Src, QualType DstTy);
299 
300   /// Emit a check that a conversion from a floating-point type does not
301   /// overflow.
302   void EmitFloatConversionCheck(Value *OrigSrc, QualType OrigSrcType,
303                                 Value *Src, QualType SrcType, QualType DstType,
304                                 llvm::Type *DstTy, SourceLocation Loc);
305 
306   /// Known implicit conversion check kinds.
307   /// Keep in sync with the enum of the same name in ubsan_handlers.h
308   enum ImplicitConversionCheckKind : unsigned char {
309     ICCK_IntegerTruncation = 0, // Legacy, was only used by clang 7.
310     ICCK_UnsignedIntegerTruncation = 1,
311     ICCK_SignedIntegerTruncation = 2,
312     ICCK_IntegerSignChange = 3,
313     ICCK_SignedIntegerTruncationOrSignChange = 4,
314   };
315 
316   /// Emit a check that an [implicit] truncation of an integer  does not
317   /// discard any bits. It is not UB, so we use the value after truncation.
318   void EmitIntegerTruncationCheck(Value *Src, QualType SrcType, Value *Dst,
319                                   QualType DstType, SourceLocation Loc);
320 
321   /// Emit a check that an [implicit] conversion of an integer does not change
322   /// the sign of the value. It is not UB, so we use the value after conversion.
323   /// NOTE: Src and Dst may be the exact same value! (point to the same thing)
324   void EmitIntegerSignChangeCheck(Value *Src, QualType SrcType, Value *Dst,
325                                   QualType DstType, SourceLocation Loc);
326 
327   /// Emit a conversion from the specified type to the specified destination
328   /// type, both of which are LLVM scalar types.
329   struct ScalarConversionOpts {
330     bool TreatBooleanAsSigned;
331     bool EmitImplicitIntegerTruncationChecks;
332     bool EmitImplicitIntegerSignChangeChecks;
333 
334     ScalarConversionOpts()
335         : TreatBooleanAsSigned(false),
336           EmitImplicitIntegerTruncationChecks(false),
337           EmitImplicitIntegerSignChangeChecks(false) {}
338 
339     ScalarConversionOpts(clang::SanitizerSet SanOpts)
340         : TreatBooleanAsSigned(false),
341           EmitImplicitIntegerTruncationChecks(
342               SanOpts.hasOneOf(SanitizerKind::ImplicitIntegerTruncation)),
343           EmitImplicitIntegerSignChangeChecks(
344               SanOpts.has(SanitizerKind::ImplicitIntegerSignChange)) {}
345   };
346   Value *EmitScalarCast(Value *Src, QualType SrcType, QualType DstType,
347                         llvm::Type *SrcTy, llvm::Type *DstTy,
348                         ScalarConversionOpts Opts);
349   Value *
350   EmitScalarConversion(Value *Src, QualType SrcTy, QualType DstTy,
351                        SourceLocation Loc,
352                        ScalarConversionOpts Opts = ScalarConversionOpts());
353 
354   /// Convert between either a fixed point and other fixed point or fixed point
355   /// and an integer.
356   Value *EmitFixedPointConversion(Value *Src, QualType SrcTy, QualType DstTy,
357                                   SourceLocation Loc);
358 
359   /// Emit a conversion from the specified complex type to the specified
360   /// destination type, where the destination type is an LLVM scalar type.
361   Value *EmitComplexToScalarConversion(CodeGenFunction::ComplexPairTy Src,
362                                        QualType SrcTy, QualType DstTy,
363                                        SourceLocation Loc);
364 
365   /// EmitNullValue - Emit a value that corresponds to null for the given type.
366   Value *EmitNullValue(QualType Ty);
367 
368   /// EmitFloatToBoolConversion - Perform an FP to boolean conversion.
369   Value *EmitFloatToBoolConversion(Value *V) {
370     // Compare against 0.0 for fp scalars.
371     llvm::Value *Zero = llvm::Constant::getNullValue(V->getType());
372     return Builder.CreateFCmpUNE(V, Zero, "tobool");
373   }
374 
375   /// EmitPointerToBoolConversion - Perform a pointer to boolean conversion.
376   Value *EmitPointerToBoolConversion(Value *V, QualType QT) {
377     Value *Zero = CGF.CGM.getNullPointer(cast<llvm::PointerType>(V->getType()), QT);
378 
379     return Builder.CreateICmpNE(V, Zero, "tobool");
380   }
381 
382   Value *EmitIntToBoolConversion(Value *V) {
383     // Because of the type rules of C, we often end up computing a
384     // logical value, then zero extending it to int, then wanting it
385     // as a logical value again.  Optimize this common case.
386     if (llvm::ZExtInst *ZI = dyn_cast<llvm::ZExtInst>(V)) {
387       if (ZI->getOperand(0)->getType() == Builder.getInt1Ty()) {
388         Value *Result = ZI->getOperand(0);
389         // If there aren't any more uses, zap the instruction to save space.
390         // Note that there can be more uses, for example if this
391         // is the result of an assignment.
392         if (ZI->use_empty())
393           ZI->eraseFromParent();
394         return Result;
395       }
396     }
397 
398     return Builder.CreateIsNotNull(V, "tobool");
399   }
400 
401   //===--------------------------------------------------------------------===//
402   //                            Visitor Methods
403   //===--------------------------------------------------------------------===//
404 
405   Value *Visit(Expr *E) {
406     ApplyDebugLocation DL(CGF, E);
407     return StmtVisitor<ScalarExprEmitter, Value*>::Visit(E);
408   }
409 
410   Value *VisitStmt(Stmt *S) {
411     S->dump(llvm::errs(), CGF.getContext());
412     llvm_unreachable("Stmt can't have complex result type!");
413   }
414   Value *VisitExpr(Expr *S);
415 
416   Value *VisitConstantExpr(ConstantExpr *E) {
417     // A constant expression of type 'void' generates no code and produces no
418     // value.
419     if (E->getType()->isVoidType())
420       return nullptr;
421 
422     if (Value *Result = ConstantEmitter(CGF).tryEmitConstantExpr(E)) {
423       if (E->isGLValue())
424         return CGF.Builder.CreateLoad(Address(
425             Result, CGF.ConvertTypeForMem(E->getType()),
426             CGF.getContext().getTypeAlignInChars(E->getType())));
427       return Result;
428     }
429     return Visit(E->getSubExpr());
430   }
431   Value *VisitParenExpr(ParenExpr *PE) {
432     return Visit(PE->getSubExpr());
433   }
434   Value *VisitSubstNonTypeTemplateParmExpr(SubstNonTypeTemplateParmExpr *E) {
435     return Visit(E->getReplacement());
436   }
437   Value *VisitGenericSelectionExpr(GenericSelectionExpr *GE) {
438     return Visit(GE->getResultExpr());
439   }
440   Value *VisitCoawaitExpr(CoawaitExpr *S) {
441     return CGF.EmitCoawaitExpr(*S).getScalarVal();
442   }
443   Value *VisitCoyieldExpr(CoyieldExpr *S) {
444     return CGF.EmitCoyieldExpr(*S).getScalarVal();
445   }
446   Value *VisitUnaryCoawait(const UnaryOperator *E) {
447     return Visit(E->getSubExpr());
448   }
449 
450   // Leaves.
451   Value *VisitIntegerLiteral(const IntegerLiteral *E) {
452     return Builder.getInt(E->getValue());
453   }
454   Value *VisitFixedPointLiteral(const FixedPointLiteral *E) {
455     return Builder.getInt(E->getValue());
456   }
457   Value *VisitFloatingLiteral(const FloatingLiteral *E) {
458     return llvm::ConstantFP::get(VMContext, E->getValue());
459   }
460   Value *VisitCharacterLiteral(const CharacterLiteral *E) {
461     return llvm::ConstantInt::get(ConvertType(E->getType()), E->getValue());
462   }
463   Value *VisitObjCBoolLiteralExpr(const ObjCBoolLiteralExpr *E) {
464     return llvm::ConstantInt::get(ConvertType(E->getType()), E->getValue());
465   }
466   Value *VisitCXXBoolLiteralExpr(const CXXBoolLiteralExpr *E) {
467     return llvm::ConstantInt::get(ConvertType(E->getType()), E->getValue());
468   }
469   Value *VisitCXXScalarValueInitExpr(const CXXScalarValueInitExpr *E) {
470     if (E->getType()->isVoidType())
471       return nullptr;
472 
473     return EmitNullValue(E->getType());
474   }
475   Value *VisitGNUNullExpr(const GNUNullExpr *E) {
476     return EmitNullValue(E->getType());
477   }
478   Value *VisitOffsetOfExpr(OffsetOfExpr *E);
479   Value *VisitUnaryExprOrTypeTraitExpr(const UnaryExprOrTypeTraitExpr *E);
480   Value *VisitAddrLabelExpr(const AddrLabelExpr *E) {
481     llvm::Value *V = CGF.GetAddrOfLabel(E->getLabel());
482     return Builder.CreateBitCast(V, ConvertType(E->getType()));
483   }
484 
485   Value *VisitSizeOfPackExpr(SizeOfPackExpr *E) {
486     return llvm::ConstantInt::get(ConvertType(E->getType()),E->getPackLength());
487   }
488 
489   Value *VisitPseudoObjectExpr(PseudoObjectExpr *E) {
490     return CGF.EmitPseudoObjectRValue(E).getScalarVal();
491   }
492 
493   Value *VisitSYCLUniqueStableNameExpr(SYCLUniqueStableNameExpr *E);
494 
495   Value *VisitOpaqueValueExpr(OpaqueValueExpr *E) {
496     if (E->isGLValue())
497       return EmitLoadOfLValue(CGF.getOrCreateOpaqueLValueMapping(E),
498                               E->getExprLoc());
499 
500     // Otherwise, assume the mapping is the scalar directly.
501     return CGF.getOrCreateOpaqueRValueMapping(E).getScalarVal();
502   }
503 
504   // l-values.
505   Value *VisitDeclRefExpr(DeclRefExpr *E) {
506     if (CodeGenFunction::ConstantEmission Constant = CGF.tryEmitAsConstant(E))
507       return CGF.emitScalarConstant(Constant, E);
508     return EmitLoadOfLValue(E);
509   }
510 
511   Value *VisitObjCSelectorExpr(ObjCSelectorExpr *E) {
512     return CGF.EmitObjCSelectorExpr(E);
513   }
514   Value *VisitObjCProtocolExpr(ObjCProtocolExpr *E) {
515     return CGF.EmitObjCProtocolExpr(E);
516   }
517   Value *VisitObjCIvarRefExpr(ObjCIvarRefExpr *E) {
518     return EmitLoadOfLValue(E);
519   }
520   Value *VisitObjCMessageExpr(ObjCMessageExpr *E) {
521     if (E->getMethodDecl() &&
522         E->getMethodDecl()->getReturnType()->isReferenceType())
523       return EmitLoadOfLValue(E);
524     return CGF.EmitObjCMessageExpr(E).getScalarVal();
525   }
526 
527   Value *VisitObjCIsaExpr(ObjCIsaExpr *E) {
528     LValue LV = CGF.EmitObjCIsaExpr(E);
529     Value *V = CGF.EmitLoadOfLValue(LV, E->getExprLoc()).getScalarVal();
530     return V;
531   }
532 
533   Value *VisitObjCAvailabilityCheckExpr(ObjCAvailabilityCheckExpr *E) {
534     VersionTuple Version = E->getVersion();
535 
536     // If we're checking for a platform older than our minimum deployment
537     // target, we can fold the check away.
538     if (Version <= CGF.CGM.getTarget().getPlatformMinVersion())
539       return llvm::ConstantInt::get(Builder.getInt1Ty(), 1);
540 
541     return CGF.EmitBuiltinAvailable(Version);
542   }
543 
544   Value *VisitArraySubscriptExpr(ArraySubscriptExpr *E);
545   Value *VisitMatrixSubscriptExpr(MatrixSubscriptExpr *E);
546   Value *VisitShuffleVectorExpr(ShuffleVectorExpr *E);
547   Value *VisitConvertVectorExpr(ConvertVectorExpr *E);
548   Value *VisitMemberExpr(MemberExpr *E);
549   Value *VisitExtVectorElementExpr(Expr *E) { return EmitLoadOfLValue(E); }
550   Value *VisitCompoundLiteralExpr(CompoundLiteralExpr *E) {
551     // Strictly speaking, we shouldn't be calling EmitLoadOfLValue, which
552     // transitively calls EmitCompoundLiteralLValue, here in C++ since compound
553     // literals aren't l-values in C++. We do so simply because that's the
554     // cleanest way to handle compound literals in C++.
555     // See the discussion here: https://reviews.llvm.org/D64464
556     return EmitLoadOfLValue(E);
557   }
558 
559   Value *VisitInitListExpr(InitListExpr *E);
560 
561   Value *VisitArrayInitIndexExpr(ArrayInitIndexExpr *E) {
562     assert(CGF.getArrayInitIndex() &&
563            "ArrayInitIndexExpr not inside an ArrayInitLoopExpr?");
564     return CGF.getArrayInitIndex();
565   }
566 
567   Value *VisitImplicitValueInitExpr(const ImplicitValueInitExpr *E) {
568     return EmitNullValue(E->getType());
569   }
570   Value *VisitExplicitCastExpr(ExplicitCastExpr *E) {
571     CGF.CGM.EmitExplicitCastExprType(E, &CGF);
572     return VisitCastExpr(E);
573   }
574   Value *VisitCastExpr(CastExpr *E);
575 
576   Value *VisitCallExpr(const CallExpr *E) {
577     if (E->getCallReturnType(CGF.getContext())->isReferenceType())
578       return EmitLoadOfLValue(E);
579 
580     Value *V = CGF.EmitCallExpr(E).getScalarVal();
581 
582     EmitLValueAlignmentAssumption(E, V);
583     return V;
584   }
585 
586   Value *VisitStmtExpr(const StmtExpr *E);
587 
588   // Unary Operators.
589   Value *VisitUnaryPostDec(const UnaryOperator *E) {
590     LValue LV = EmitLValue(E->getSubExpr());
591     return EmitScalarPrePostIncDec(E, LV, false, false);
592   }
593   Value *VisitUnaryPostInc(const UnaryOperator *E) {
594     LValue LV = EmitLValue(E->getSubExpr());
595     return EmitScalarPrePostIncDec(E, LV, true, false);
596   }
597   Value *VisitUnaryPreDec(const UnaryOperator *E) {
598     LValue LV = EmitLValue(E->getSubExpr());
599     return EmitScalarPrePostIncDec(E, LV, false, true);
600   }
601   Value *VisitUnaryPreInc(const UnaryOperator *E) {
602     LValue LV = EmitLValue(E->getSubExpr());
603     return EmitScalarPrePostIncDec(E, LV, true, true);
604   }
605 
606   llvm::Value *EmitIncDecConsiderOverflowBehavior(const UnaryOperator *E,
607                                                   llvm::Value *InVal,
608                                                   bool IsInc);
609 
610   llvm::Value *EmitScalarPrePostIncDec(const UnaryOperator *E, LValue LV,
611                                        bool isInc, bool isPre);
612 
613 
614   Value *VisitUnaryAddrOf(const UnaryOperator *E) {
615     if (isa<MemberPointerType>(E->getType())) // never sugared
616       return CGF.CGM.getMemberPointerConstant(E);
617 
618     return EmitLValue(E->getSubExpr()).getPointer(CGF);
619   }
620   Value *VisitUnaryDeref(const UnaryOperator *E) {
621     if (E->getType()->isVoidType())
622       return Visit(E->getSubExpr()); // the actual value should be unused
623     return EmitLoadOfLValue(E);
624   }
625 
626   Value *VisitUnaryPlus(const UnaryOperator *E,
627                         QualType PromotionType = QualType());
628   Value *VisitPlus(const UnaryOperator *E, QualType PromotionType);
629   Value *VisitUnaryMinus(const UnaryOperator *E,
630                          QualType PromotionType = QualType());
631   Value *VisitMinus(const UnaryOperator *E, QualType PromotionType);
632 
633   Value *VisitUnaryNot      (const UnaryOperator *E);
634   Value *VisitUnaryLNot     (const UnaryOperator *E);
635   Value *VisitUnaryReal(const UnaryOperator *E,
636                         QualType PromotionType = QualType());
637   Value *VisitReal(const UnaryOperator *E, QualType PromotionType);
638   Value *VisitUnaryImag(const UnaryOperator *E,
639                         QualType PromotionType = QualType());
640   Value *VisitImag(const UnaryOperator *E, QualType PromotionType);
641   Value *VisitUnaryExtension(const UnaryOperator *E) {
642     return Visit(E->getSubExpr());
643   }
644 
645   // C++
646   Value *VisitMaterializeTemporaryExpr(const MaterializeTemporaryExpr *E) {
647     return EmitLoadOfLValue(E);
648   }
649   Value *VisitSourceLocExpr(SourceLocExpr *SLE) {
650     auto &Ctx = CGF.getContext();
651     APValue Evaluated =
652         SLE->EvaluateInContext(Ctx, CGF.CurSourceLocExprScope.getDefaultExpr());
653     return ConstantEmitter(CGF).emitAbstract(SLE->getLocation(), Evaluated,
654                                              SLE->getType());
655   }
656 
657   Value *VisitCXXDefaultArgExpr(CXXDefaultArgExpr *DAE) {
658     CodeGenFunction::CXXDefaultArgExprScope Scope(CGF, DAE);
659     return Visit(DAE->getExpr());
660   }
661   Value *VisitCXXDefaultInitExpr(CXXDefaultInitExpr *DIE) {
662     CodeGenFunction::CXXDefaultInitExprScope Scope(CGF, DIE);
663     return Visit(DIE->getExpr());
664   }
665   Value *VisitCXXThisExpr(CXXThisExpr *TE) {
666     return CGF.LoadCXXThis();
667   }
668 
669   Value *VisitExprWithCleanups(ExprWithCleanups *E);
670   Value *VisitCXXNewExpr(const CXXNewExpr *E) {
671     return CGF.EmitCXXNewExpr(E);
672   }
673   Value *VisitCXXDeleteExpr(const CXXDeleteExpr *E) {
674     CGF.EmitCXXDeleteExpr(E);
675     return nullptr;
676   }
677 
678   Value *VisitTypeTraitExpr(const TypeTraitExpr *E) {
679     return llvm::ConstantInt::get(ConvertType(E->getType()), E->getValue());
680   }
681 
682   Value *VisitConceptSpecializationExpr(const ConceptSpecializationExpr *E) {
683     return Builder.getInt1(E->isSatisfied());
684   }
685 
686   Value *VisitRequiresExpr(const RequiresExpr *E) {
687     return Builder.getInt1(E->isSatisfied());
688   }
689 
690   Value *VisitArrayTypeTraitExpr(const ArrayTypeTraitExpr *E) {
691     return llvm::ConstantInt::get(Builder.getInt32Ty(), E->getValue());
692   }
693 
694   Value *VisitExpressionTraitExpr(const ExpressionTraitExpr *E) {
695     return llvm::ConstantInt::get(Builder.getInt1Ty(), E->getValue());
696   }
697 
698   Value *VisitCXXPseudoDestructorExpr(const CXXPseudoDestructorExpr *E) {
699     // C++ [expr.pseudo]p1:
700     //   The result shall only be used as the operand for the function call
701     //   operator (), and the result of such a call has type void. The only
702     //   effect is the evaluation of the postfix-expression before the dot or
703     //   arrow.
704     CGF.EmitScalarExpr(E->getBase());
705     return nullptr;
706   }
707 
708   Value *VisitCXXNullPtrLiteralExpr(const CXXNullPtrLiteralExpr *E) {
709     return EmitNullValue(E->getType());
710   }
711 
712   Value *VisitCXXThrowExpr(const CXXThrowExpr *E) {
713     CGF.EmitCXXThrowExpr(E);
714     return nullptr;
715   }
716 
717   Value *VisitCXXNoexceptExpr(const CXXNoexceptExpr *E) {
718     return Builder.getInt1(E->getValue());
719   }
720 
721   // Binary Operators.
722   Value *EmitMul(const BinOpInfo &Ops) {
723     if (Ops.Ty->isSignedIntegerOrEnumerationType()) {
724       switch (CGF.getLangOpts().getSignedOverflowBehavior()) {
725       case LangOptions::SOB_Defined:
726         return Builder.CreateMul(Ops.LHS, Ops.RHS, "mul");
727       case LangOptions::SOB_Undefined:
728         if (!CGF.SanOpts.has(SanitizerKind::SignedIntegerOverflow))
729           return Builder.CreateNSWMul(Ops.LHS, Ops.RHS, "mul");
730         [[fallthrough]];
731       case LangOptions::SOB_Trapping:
732         if (CanElideOverflowCheck(CGF.getContext(), Ops))
733           return Builder.CreateNSWMul(Ops.LHS, Ops.RHS, "mul");
734         return EmitOverflowCheckedBinOp(Ops);
735       }
736     }
737 
738     if (Ops.Ty->isConstantMatrixType()) {
739       llvm::MatrixBuilder MB(Builder);
740       // We need to check the types of the operands of the operator to get the
741       // correct matrix dimensions.
742       auto *BO = cast<BinaryOperator>(Ops.E);
743       auto *LHSMatTy = dyn_cast<ConstantMatrixType>(
744           BO->getLHS()->getType().getCanonicalType());
745       auto *RHSMatTy = dyn_cast<ConstantMatrixType>(
746           BO->getRHS()->getType().getCanonicalType());
747       CodeGenFunction::CGFPOptionsRAII FPOptsRAII(CGF, Ops.FPFeatures);
748       if (LHSMatTy && RHSMatTy)
749         return MB.CreateMatrixMultiply(Ops.LHS, Ops.RHS, LHSMatTy->getNumRows(),
750                                        LHSMatTy->getNumColumns(),
751                                        RHSMatTy->getNumColumns());
752       return MB.CreateScalarMultiply(Ops.LHS, Ops.RHS);
753     }
754 
755     if (Ops.Ty->isUnsignedIntegerType() &&
756         CGF.SanOpts.has(SanitizerKind::UnsignedIntegerOverflow) &&
757         !CanElideOverflowCheck(CGF.getContext(), Ops))
758       return EmitOverflowCheckedBinOp(Ops);
759 
760     if (Ops.LHS->getType()->isFPOrFPVectorTy()) {
761       //  Preserve the old values
762       CodeGenFunction::CGFPOptionsRAII FPOptsRAII(CGF, Ops.FPFeatures);
763       return Builder.CreateFMul(Ops.LHS, Ops.RHS, "mul");
764     }
765     if (Ops.isFixedPointOp())
766       return EmitFixedPointBinOp(Ops);
767     return Builder.CreateMul(Ops.LHS, Ops.RHS, "mul");
768   }
769   /// Create a binary op that checks for overflow.
770   /// Currently only supports +, - and *.
771   Value *EmitOverflowCheckedBinOp(const BinOpInfo &Ops);
772 
773   // Check for undefined division and modulus behaviors.
774   void EmitUndefinedBehaviorIntegerDivAndRemCheck(const BinOpInfo &Ops,
775                                                   llvm::Value *Zero,bool isDiv);
776   // Common helper for getting how wide LHS of shift is.
777   static Value *GetWidthMinusOneValue(Value* LHS,Value* RHS);
778 
779   // Used for shifting constraints for OpenCL, do mask for powers of 2, URem for
780   // non powers of two.
781   Value *ConstrainShiftValue(Value *LHS, Value *RHS, const Twine &Name);
782 
783   Value *EmitDiv(const BinOpInfo &Ops);
784   Value *EmitRem(const BinOpInfo &Ops);
785   Value *EmitAdd(const BinOpInfo &Ops);
786   Value *EmitSub(const BinOpInfo &Ops);
787   Value *EmitShl(const BinOpInfo &Ops);
788   Value *EmitShr(const BinOpInfo &Ops);
789   Value *EmitAnd(const BinOpInfo &Ops) {
790     return Builder.CreateAnd(Ops.LHS, Ops.RHS, "and");
791   }
792   Value *EmitXor(const BinOpInfo &Ops) {
793     return Builder.CreateXor(Ops.LHS, Ops.RHS, "xor");
794   }
795   Value *EmitOr (const BinOpInfo &Ops) {
796     return Builder.CreateOr(Ops.LHS, Ops.RHS, "or");
797   }
798 
799   // Helper functions for fixed point binary operations.
800   Value *EmitFixedPointBinOp(const BinOpInfo &Ops);
801 
802   BinOpInfo EmitBinOps(const BinaryOperator *E,
803                        QualType PromotionTy = QualType());
804 
805   Value *EmitPromotedValue(Value *result, QualType PromotionType);
806   Value *EmitUnPromotedValue(Value *result, QualType ExprType);
807   Value *EmitPromoted(const Expr *E, QualType PromotionType);
808 
809   LValue EmitCompoundAssignLValue(const CompoundAssignOperator *E,
810                             Value *(ScalarExprEmitter::*F)(const BinOpInfo &),
811                                   Value *&Result);
812 
813   Value *EmitCompoundAssign(const CompoundAssignOperator *E,
814                             Value *(ScalarExprEmitter::*F)(const BinOpInfo &));
815 
816   QualType getPromotionType(QualType Ty) {
817     const auto &Ctx = CGF.getContext();
818     if (auto *CT = Ty->getAs<ComplexType>()) {
819       QualType ElementType = CT->getElementType();
820       if (ElementType.UseExcessPrecision(Ctx))
821         return Ctx.getComplexType(Ctx.FloatTy);
822     }
823 
824     if (Ty.UseExcessPrecision(Ctx)) {
825       if (auto *VT = Ty->getAs<VectorType>()) {
826         unsigned NumElements = VT->getNumElements();
827         return Ctx.getVectorType(Ctx.FloatTy, NumElements, VT->getVectorKind());
828       }
829       return Ctx.FloatTy;
830     }
831 
832     return QualType();
833   }
834 
835   // Binary operators and binary compound assignment operators.
836 #define HANDLEBINOP(OP)                                                        \
837   Value *VisitBin##OP(const BinaryOperator *E) {                               \
838     QualType promotionTy = getPromotionType(E->getType());                     \
839     auto result = Emit##OP(EmitBinOps(E, promotionTy));                        \
840     if (result && !promotionTy.isNull())                                       \
841       result = EmitUnPromotedValue(result, E->getType());                      \
842     return result;                                                             \
843   }                                                                            \
844   Value *VisitBin##OP##Assign(const CompoundAssignOperator *E) {               \
845     return EmitCompoundAssign(E, &ScalarExprEmitter::Emit##OP);                \
846   }
847   HANDLEBINOP(Mul)
848   HANDLEBINOP(Div)
849   HANDLEBINOP(Rem)
850   HANDLEBINOP(Add)
851   HANDLEBINOP(Sub)
852   HANDLEBINOP(Shl)
853   HANDLEBINOP(Shr)
854   HANDLEBINOP(And)
855   HANDLEBINOP(Xor)
856   HANDLEBINOP(Or)
857 #undef HANDLEBINOP
858 
859   // Comparisons.
860   Value *EmitCompare(const BinaryOperator *E, llvm::CmpInst::Predicate UICmpOpc,
861                      llvm::CmpInst::Predicate SICmpOpc,
862                      llvm::CmpInst::Predicate FCmpOpc, bool IsSignaling);
863 #define VISITCOMP(CODE, UI, SI, FP, SIG) \
864     Value *VisitBin##CODE(const BinaryOperator *E) { \
865       return EmitCompare(E, llvm::ICmpInst::UI, llvm::ICmpInst::SI, \
866                          llvm::FCmpInst::FP, SIG); }
867   VISITCOMP(LT, ICMP_ULT, ICMP_SLT, FCMP_OLT, true)
868   VISITCOMP(GT, ICMP_UGT, ICMP_SGT, FCMP_OGT, true)
869   VISITCOMP(LE, ICMP_ULE, ICMP_SLE, FCMP_OLE, true)
870   VISITCOMP(GE, ICMP_UGE, ICMP_SGE, FCMP_OGE, true)
871   VISITCOMP(EQ, ICMP_EQ , ICMP_EQ , FCMP_OEQ, false)
872   VISITCOMP(NE, ICMP_NE , ICMP_NE , FCMP_UNE, false)
873 #undef VISITCOMP
874 
875   Value *VisitBinAssign     (const BinaryOperator *E);
876 
877   Value *VisitBinLAnd       (const BinaryOperator *E);
878   Value *VisitBinLOr        (const BinaryOperator *E);
879   Value *VisitBinComma      (const BinaryOperator *E);
880 
881   Value *VisitBinPtrMemD(const Expr *E) { return EmitLoadOfLValue(E); }
882   Value *VisitBinPtrMemI(const Expr *E) { return EmitLoadOfLValue(E); }
883 
884   Value *VisitCXXRewrittenBinaryOperator(CXXRewrittenBinaryOperator *E) {
885     return Visit(E->getSemanticForm());
886   }
887 
888   // Other Operators.
889   Value *VisitBlockExpr(const BlockExpr *BE);
890   Value *VisitAbstractConditionalOperator(const AbstractConditionalOperator *);
891   Value *VisitChooseExpr(ChooseExpr *CE);
892   Value *VisitVAArgExpr(VAArgExpr *VE);
893   Value *VisitObjCStringLiteral(const ObjCStringLiteral *E) {
894     return CGF.EmitObjCStringLiteral(E);
895   }
896   Value *VisitObjCBoxedExpr(ObjCBoxedExpr *E) {
897     return CGF.EmitObjCBoxedExpr(E);
898   }
899   Value *VisitObjCArrayLiteral(ObjCArrayLiteral *E) {
900     return CGF.EmitObjCArrayLiteral(E);
901   }
902   Value *VisitObjCDictionaryLiteral(ObjCDictionaryLiteral *E) {
903     return CGF.EmitObjCDictionaryLiteral(E);
904   }
905   Value *VisitAsTypeExpr(AsTypeExpr *CE);
906   Value *VisitAtomicExpr(AtomicExpr *AE);
907 };
908 }  // end anonymous namespace.
909 
910 //===----------------------------------------------------------------------===//
911 //                                Utilities
912 //===----------------------------------------------------------------------===//
913 
914 /// EmitConversionToBool - Convert the specified expression value to a
915 /// boolean (i1) truth value.  This is equivalent to "Val != 0".
916 Value *ScalarExprEmitter::EmitConversionToBool(Value *Src, QualType SrcType) {
917   assert(SrcType.isCanonical() && "EmitScalarConversion strips typedefs");
918 
919   if (SrcType->isRealFloatingType())
920     return EmitFloatToBoolConversion(Src);
921 
922   if (const MemberPointerType *MPT = dyn_cast<MemberPointerType>(SrcType))
923     return CGF.CGM.getCXXABI().EmitMemberPointerIsNotNull(CGF, Src, MPT);
924 
925   assert((SrcType->isIntegerType() || isa<llvm::PointerType>(Src->getType())) &&
926          "Unknown scalar type to convert");
927 
928   if (isa<llvm::IntegerType>(Src->getType()))
929     return EmitIntToBoolConversion(Src);
930 
931   assert(isa<llvm::PointerType>(Src->getType()));
932   return EmitPointerToBoolConversion(Src, SrcType);
933 }
934 
935 void ScalarExprEmitter::EmitFloatConversionCheck(
936     Value *OrigSrc, QualType OrigSrcType, Value *Src, QualType SrcType,
937     QualType DstType, llvm::Type *DstTy, SourceLocation Loc) {
938   assert(SrcType->isFloatingType() && "not a conversion from floating point");
939   if (!isa<llvm::IntegerType>(DstTy))
940     return;
941 
942   CodeGenFunction::SanitizerScope SanScope(&CGF);
943   using llvm::APFloat;
944   using llvm::APSInt;
945 
946   llvm::Value *Check = nullptr;
947   const llvm::fltSemantics &SrcSema =
948     CGF.getContext().getFloatTypeSemantics(OrigSrcType);
949 
950   // Floating-point to integer. This has undefined behavior if the source is
951   // +-Inf, NaN, or doesn't fit into the destination type (after truncation
952   // to an integer).
953   unsigned Width = CGF.getContext().getIntWidth(DstType);
954   bool Unsigned = DstType->isUnsignedIntegerOrEnumerationType();
955 
956   APSInt Min = APSInt::getMinValue(Width, Unsigned);
957   APFloat MinSrc(SrcSema, APFloat::uninitialized);
958   if (MinSrc.convertFromAPInt(Min, !Unsigned, APFloat::rmTowardZero) &
959       APFloat::opOverflow)
960     // Don't need an overflow check for lower bound. Just check for
961     // -Inf/NaN.
962     MinSrc = APFloat::getInf(SrcSema, true);
963   else
964     // Find the largest value which is too small to represent (before
965     // truncation toward zero).
966     MinSrc.subtract(APFloat(SrcSema, 1), APFloat::rmTowardNegative);
967 
968   APSInt Max = APSInt::getMaxValue(Width, Unsigned);
969   APFloat MaxSrc(SrcSema, APFloat::uninitialized);
970   if (MaxSrc.convertFromAPInt(Max, !Unsigned, APFloat::rmTowardZero) &
971       APFloat::opOverflow)
972     // Don't need an overflow check for upper bound. Just check for
973     // +Inf/NaN.
974     MaxSrc = APFloat::getInf(SrcSema, false);
975   else
976     // Find the smallest value which is too large to represent (before
977     // truncation toward zero).
978     MaxSrc.add(APFloat(SrcSema, 1), APFloat::rmTowardPositive);
979 
980   // If we're converting from __half, convert the range to float to match
981   // the type of src.
982   if (OrigSrcType->isHalfType()) {
983     const llvm::fltSemantics &Sema =
984       CGF.getContext().getFloatTypeSemantics(SrcType);
985     bool IsInexact;
986     MinSrc.convert(Sema, APFloat::rmTowardZero, &IsInexact);
987     MaxSrc.convert(Sema, APFloat::rmTowardZero, &IsInexact);
988   }
989 
990   llvm::Value *GE =
991     Builder.CreateFCmpOGT(Src, llvm::ConstantFP::get(VMContext, MinSrc));
992   llvm::Value *LE =
993     Builder.CreateFCmpOLT(Src, llvm::ConstantFP::get(VMContext, MaxSrc));
994   Check = Builder.CreateAnd(GE, LE);
995 
996   llvm::Constant *StaticArgs[] = {CGF.EmitCheckSourceLocation(Loc),
997                                   CGF.EmitCheckTypeDescriptor(OrigSrcType),
998                                   CGF.EmitCheckTypeDescriptor(DstType)};
999   CGF.EmitCheck(std::make_pair(Check, SanitizerKind::FloatCastOverflow),
1000                 SanitizerHandler::FloatCastOverflow, StaticArgs, OrigSrc);
1001 }
1002 
1003 // Should be called within CodeGenFunction::SanitizerScope RAII scope.
1004 // Returns 'i1 false' when the truncation Src -> Dst was lossy.
1005 static std::pair<ScalarExprEmitter::ImplicitConversionCheckKind,
1006                  std::pair<llvm::Value *, SanitizerMask>>
1007 EmitIntegerTruncationCheckHelper(Value *Src, QualType SrcType, Value *Dst,
1008                                  QualType DstType, CGBuilderTy &Builder) {
1009   llvm::Type *SrcTy = Src->getType();
1010   llvm::Type *DstTy = Dst->getType();
1011   (void)DstTy; // Only used in assert()
1012 
1013   // This should be truncation of integral types.
1014   assert(Src != Dst);
1015   assert(SrcTy->getScalarSizeInBits() > Dst->getType()->getScalarSizeInBits());
1016   assert(isa<llvm::IntegerType>(SrcTy) && isa<llvm::IntegerType>(DstTy) &&
1017          "non-integer llvm type");
1018 
1019   bool SrcSigned = SrcType->isSignedIntegerOrEnumerationType();
1020   bool DstSigned = DstType->isSignedIntegerOrEnumerationType();
1021 
1022   // If both (src and dst) types are unsigned, then it's an unsigned truncation.
1023   // Else, it is a signed truncation.
1024   ScalarExprEmitter::ImplicitConversionCheckKind Kind;
1025   SanitizerMask Mask;
1026   if (!SrcSigned && !DstSigned) {
1027     Kind = ScalarExprEmitter::ICCK_UnsignedIntegerTruncation;
1028     Mask = SanitizerKind::ImplicitUnsignedIntegerTruncation;
1029   } else {
1030     Kind = ScalarExprEmitter::ICCK_SignedIntegerTruncation;
1031     Mask = SanitizerKind::ImplicitSignedIntegerTruncation;
1032   }
1033 
1034   llvm::Value *Check = nullptr;
1035   // 1. Extend the truncated value back to the same width as the Src.
1036   Check = Builder.CreateIntCast(Dst, SrcTy, DstSigned, "anyext");
1037   // 2. Equality-compare with the original source value
1038   Check = Builder.CreateICmpEQ(Check, Src, "truncheck");
1039   // If the comparison result is 'i1 false', then the truncation was lossy.
1040   return std::make_pair(Kind, std::make_pair(Check, Mask));
1041 }
1042 
1043 static bool PromotionIsPotentiallyEligibleForImplicitIntegerConversionCheck(
1044     QualType SrcType, QualType DstType) {
1045   return SrcType->isIntegerType() && DstType->isIntegerType();
1046 }
1047 
1048 void ScalarExprEmitter::EmitIntegerTruncationCheck(Value *Src, QualType SrcType,
1049                                                    Value *Dst, QualType DstType,
1050                                                    SourceLocation Loc) {
1051   if (!CGF.SanOpts.hasOneOf(SanitizerKind::ImplicitIntegerTruncation))
1052     return;
1053 
1054   // We only care about int->int conversions here.
1055   // We ignore conversions to/from pointer and/or bool.
1056   if (!PromotionIsPotentiallyEligibleForImplicitIntegerConversionCheck(SrcType,
1057                                                                        DstType))
1058     return;
1059 
1060   unsigned SrcBits = Src->getType()->getScalarSizeInBits();
1061   unsigned DstBits = Dst->getType()->getScalarSizeInBits();
1062   // This must be truncation. Else we do not care.
1063   if (SrcBits <= DstBits)
1064     return;
1065 
1066   assert(!DstType->isBooleanType() && "we should not get here with booleans.");
1067 
1068   // If the integer sign change sanitizer is enabled,
1069   // and we are truncating from larger unsigned type to smaller signed type,
1070   // let that next sanitizer deal with it.
1071   bool SrcSigned = SrcType->isSignedIntegerOrEnumerationType();
1072   bool DstSigned = DstType->isSignedIntegerOrEnumerationType();
1073   if (CGF.SanOpts.has(SanitizerKind::ImplicitIntegerSignChange) &&
1074       (!SrcSigned && DstSigned))
1075     return;
1076 
1077   CodeGenFunction::SanitizerScope SanScope(&CGF);
1078 
1079   std::pair<ScalarExprEmitter::ImplicitConversionCheckKind,
1080             std::pair<llvm::Value *, SanitizerMask>>
1081       Check =
1082           EmitIntegerTruncationCheckHelper(Src, SrcType, Dst, DstType, Builder);
1083   // If the comparison result is 'i1 false', then the truncation was lossy.
1084 
1085   // Do we care about this type of truncation?
1086   if (!CGF.SanOpts.has(Check.second.second))
1087     return;
1088 
1089   llvm::Constant *StaticArgs[] = {
1090       CGF.EmitCheckSourceLocation(Loc), CGF.EmitCheckTypeDescriptor(SrcType),
1091       CGF.EmitCheckTypeDescriptor(DstType),
1092       llvm::ConstantInt::get(Builder.getInt8Ty(), Check.first)};
1093   CGF.EmitCheck(Check.second, SanitizerHandler::ImplicitConversion, StaticArgs,
1094                 {Src, Dst});
1095 }
1096 
1097 // Should be called within CodeGenFunction::SanitizerScope RAII scope.
1098 // Returns 'i1 false' when the conversion Src -> Dst changed the sign.
1099 static std::pair<ScalarExprEmitter::ImplicitConversionCheckKind,
1100                  std::pair<llvm::Value *, SanitizerMask>>
1101 EmitIntegerSignChangeCheckHelper(Value *Src, QualType SrcType, Value *Dst,
1102                                  QualType DstType, CGBuilderTy &Builder) {
1103   llvm::Type *SrcTy = Src->getType();
1104   llvm::Type *DstTy = Dst->getType();
1105 
1106   assert(isa<llvm::IntegerType>(SrcTy) && isa<llvm::IntegerType>(DstTy) &&
1107          "non-integer llvm type");
1108 
1109   bool SrcSigned = SrcType->isSignedIntegerOrEnumerationType();
1110   bool DstSigned = DstType->isSignedIntegerOrEnumerationType();
1111   (void)SrcSigned; // Only used in assert()
1112   (void)DstSigned; // Only used in assert()
1113   unsigned SrcBits = SrcTy->getScalarSizeInBits();
1114   unsigned DstBits = DstTy->getScalarSizeInBits();
1115   (void)SrcBits; // Only used in assert()
1116   (void)DstBits; // Only used in assert()
1117 
1118   assert(((SrcBits != DstBits) || (SrcSigned != DstSigned)) &&
1119          "either the widths should be different, or the signednesses.");
1120 
1121   // NOTE: zero value is considered to be non-negative.
1122   auto EmitIsNegativeTest = [&Builder](Value *V, QualType VType,
1123                                        const char *Name) -> Value * {
1124     // Is this value a signed type?
1125     bool VSigned = VType->isSignedIntegerOrEnumerationType();
1126     llvm::Type *VTy = V->getType();
1127     if (!VSigned) {
1128       // If the value is unsigned, then it is never negative.
1129       // FIXME: can we encounter non-scalar VTy here?
1130       return llvm::ConstantInt::getFalse(VTy->getContext());
1131     }
1132     // Get the zero of the same type with which we will be comparing.
1133     llvm::Constant *Zero = llvm::ConstantInt::get(VTy, 0);
1134     // %V.isnegative = icmp slt %V, 0
1135     // I.e is %V *strictly* less than zero, does it have negative value?
1136     return Builder.CreateICmp(llvm::ICmpInst::ICMP_SLT, V, Zero,
1137                               llvm::Twine(Name) + "." + V->getName() +
1138                                   ".negativitycheck");
1139   };
1140 
1141   // 1. Was the old Value negative?
1142   llvm::Value *SrcIsNegative = EmitIsNegativeTest(Src, SrcType, "src");
1143   // 2. Is the new Value negative?
1144   llvm::Value *DstIsNegative = EmitIsNegativeTest(Dst, DstType, "dst");
1145   // 3. Now, was the 'negativity status' preserved during the conversion?
1146   //    NOTE: conversion from negative to zero is considered to change the sign.
1147   //    (We want to get 'false' when the conversion changed the sign)
1148   //    So we should just equality-compare the negativity statuses.
1149   llvm::Value *Check = nullptr;
1150   Check = Builder.CreateICmpEQ(SrcIsNegative, DstIsNegative, "signchangecheck");
1151   // If the comparison result is 'false', then the conversion changed the sign.
1152   return std::make_pair(
1153       ScalarExprEmitter::ICCK_IntegerSignChange,
1154       std::make_pair(Check, SanitizerKind::ImplicitIntegerSignChange));
1155 }
1156 
1157 void ScalarExprEmitter::EmitIntegerSignChangeCheck(Value *Src, QualType SrcType,
1158                                                    Value *Dst, QualType DstType,
1159                                                    SourceLocation Loc) {
1160   if (!CGF.SanOpts.has(SanitizerKind::ImplicitIntegerSignChange))
1161     return;
1162 
1163   llvm::Type *SrcTy = Src->getType();
1164   llvm::Type *DstTy = Dst->getType();
1165 
1166   // We only care about int->int conversions here.
1167   // We ignore conversions to/from pointer and/or bool.
1168   if (!PromotionIsPotentiallyEligibleForImplicitIntegerConversionCheck(SrcType,
1169                                                                        DstType))
1170     return;
1171 
1172   bool SrcSigned = SrcType->isSignedIntegerOrEnumerationType();
1173   bool DstSigned = DstType->isSignedIntegerOrEnumerationType();
1174   unsigned SrcBits = SrcTy->getScalarSizeInBits();
1175   unsigned DstBits = DstTy->getScalarSizeInBits();
1176 
1177   // Now, we do not need to emit the check in *all* of the cases.
1178   // We can avoid emitting it in some obvious cases where it would have been
1179   // dropped by the opt passes (instcombine) always anyways.
1180   // If it's a cast between effectively the same type, no check.
1181   // NOTE: this is *not* equivalent to checking the canonical types.
1182   if (SrcSigned == DstSigned && SrcBits == DstBits)
1183     return;
1184   // At least one of the values needs to have signed type.
1185   // If both are unsigned, then obviously, neither of them can be negative.
1186   if (!SrcSigned && !DstSigned)
1187     return;
1188   // If the conversion is to *larger* *signed* type, then no check is needed.
1189   // Because either sign-extension happens (so the sign will remain),
1190   // or zero-extension will happen (the sign bit will be zero.)
1191   if ((DstBits > SrcBits) && DstSigned)
1192     return;
1193   if (CGF.SanOpts.has(SanitizerKind::ImplicitSignedIntegerTruncation) &&
1194       (SrcBits > DstBits) && SrcSigned) {
1195     // If the signed integer truncation sanitizer is enabled,
1196     // and this is a truncation from signed type, then no check is needed.
1197     // Because here sign change check is interchangeable with truncation check.
1198     return;
1199   }
1200   // That's it. We can't rule out any more cases with the data we have.
1201 
1202   CodeGenFunction::SanitizerScope SanScope(&CGF);
1203 
1204   std::pair<ScalarExprEmitter::ImplicitConversionCheckKind,
1205             std::pair<llvm::Value *, SanitizerMask>>
1206       Check;
1207 
1208   // Each of these checks needs to return 'false' when an issue was detected.
1209   ImplicitConversionCheckKind CheckKind;
1210   llvm::SmallVector<std::pair<llvm::Value *, SanitizerMask>, 2> Checks;
1211   // So we can 'and' all the checks together, and still get 'false',
1212   // if at least one of the checks detected an issue.
1213 
1214   Check = EmitIntegerSignChangeCheckHelper(Src, SrcType, Dst, DstType, Builder);
1215   CheckKind = Check.first;
1216   Checks.emplace_back(Check.second);
1217 
1218   if (CGF.SanOpts.has(SanitizerKind::ImplicitSignedIntegerTruncation) &&
1219       (SrcBits > DstBits) && !SrcSigned && DstSigned) {
1220     // If the signed integer truncation sanitizer was enabled,
1221     // and we are truncating from larger unsigned type to smaller signed type,
1222     // let's handle the case we skipped in that check.
1223     Check =
1224         EmitIntegerTruncationCheckHelper(Src, SrcType, Dst, DstType, Builder);
1225     CheckKind = ICCK_SignedIntegerTruncationOrSignChange;
1226     Checks.emplace_back(Check.second);
1227     // If the comparison result is 'i1 false', then the truncation was lossy.
1228   }
1229 
1230   llvm::Constant *StaticArgs[] = {
1231       CGF.EmitCheckSourceLocation(Loc), CGF.EmitCheckTypeDescriptor(SrcType),
1232       CGF.EmitCheckTypeDescriptor(DstType),
1233       llvm::ConstantInt::get(Builder.getInt8Ty(), CheckKind)};
1234   // EmitCheck() will 'and' all the checks together.
1235   CGF.EmitCheck(Checks, SanitizerHandler::ImplicitConversion, StaticArgs,
1236                 {Src, Dst});
1237 }
1238 
1239 Value *ScalarExprEmitter::EmitScalarCast(Value *Src, QualType SrcType,
1240                                          QualType DstType, llvm::Type *SrcTy,
1241                                          llvm::Type *DstTy,
1242                                          ScalarConversionOpts Opts) {
1243   // The Element types determine the type of cast to perform.
1244   llvm::Type *SrcElementTy;
1245   llvm::Type *DstElementTy;
1246   QualType SrcElementType;
1247   QualType DstElementType;
1248   if (SrcType->isMatrixType() && DstType->isMatrixType()) {
1249     SrcElementTy = cast<llvm::VectorType>(SrcTy)->getElementType();
1250     DstElementTy = cast<llvm::VectorType>(DstTy)->getElementType();
1251     SrcElementType = SrcType->castAs<MatrixType>()->getElementType();
1252     DstElementType = DstType->castAs<MatrixType>()->getElementType();
1253   } else {
1254     assert(!SrcType->isMatrixType() && !DstType->isMatrixType() &&
1255            "cannot cast between matrix and non-matrix types");
1256     SrcElementTy = SrcTy;
1257     DstElementTy = DstTy;
1258     SrcElementType = SrcType;
1259     DstElementType = DstType;
1260   }
1261 
1262   if (isa<llvm::IntegerType>(SrcElementTy)) {
1263     bool InputSigned = SrcElementType->isSignedIntegerOrEnumerationType();
1264     if (SrcElementType->isBooleanType() && Opts.TreatBooleanAsSigned) {
1265       InputSigned = true;
1266     }
1267 
1268     if (isa<llvm::IntegerType>(DstElementTy))
1269       return Builder.CreateIntCast(Src, DstTy, InputSigned, "conv");
1270     if (InputSigned)
1271       return Builder.CreateSIToFP(Src, DstTy, "conv");
1272     return Builder.CreateUIToFP(Src, DstTy, "conv");
1273   }
1274 
1275   if (isa<llvm::IntegerType>(DstElementTy)) {
1276     assert(SrcElementTy->isFloatingPointTy() && "Unknown real conversion");
1277     bool IsSigned = DstElementType->isSignedIntegerOrEnumerationType();
1278 
1279     // If we can't recognize overflow as undefined behavior, assume that
1280     // overflow saturates. This protects against normal optimizations if we are
1281     // compiling with non-standard FP semantics.
1282     if (!CGF.CGM.getCodeGenOpts().StrictFloatCastOverflow) {
1283       llvm::Intrinsic::ID IID =
1284           IsSigned ? llvm::Intrinsic::fptosi_sat : llvm::Intrinsic::fptoui_sat;
1285       return Builder.CreateCall(CGF.CGM.getIntrinsic(IID, {DstTy, SrcTy}), Src);
1286     }
1287 
1288     if (IsSigned)
1289       return Builder.CreateFPToSI(Src, DstTy, "conv");
1290     return Builder.CreateFPToUI(Src, DstTy, "conv");
1291   }
1292 
1293   if (DstElementTy->getTypeID() < SrcElementTy->getTypeID())
1294     return Builder.CreateFPTrunc(Src, DstTy, "conv");
1295   return Builder.CreateFPExt(Src, DstTy, "conv");
1296 }
1297 
1298 /// Emit a conversion from the specified type to the specified destination type,
1299 /// both of which are LLVM scalar types.
1300 Value *ScalarExprEmitter::EmitScalarConversion(Value *Src, QualType SrcType,
1301                                                QualType DstType,
1302                                                SourceLocation Loc,
1303                                                ScalarConversionOpts Opts) {
1304   // All conversions involving fixed point types should be handled by the
1305   // EmitFixedPoint family functions. This is done to prevent bloating up this
1306   // function more, and although fixed point numbers are represented by
1307   // integers, we do not want to follow any logic that assumes they should be
1308   // treated as integers.
1309   // TODO(leonardchan): When necessary, add another if statement checking for
1310   // conversions to fixed point types from other types.
1311   if (SrcType->isFixedPointType()) {
1312     if (DstType->isBooleanType())
1313       // It is important that we check this before checking if the dest type is
1314       // an integer because booleans are technically integer types.
1315       // We do not need to check the padding bit on unsigned types if unsigned
1316       // padding is enabled because overflow into this bit is undefined
1317       // behavior.
1318       return Builder.CreateIsNotNull(Src, "tobool");
1319     if (DstType->isFixedPointType() || DstType->isIntegerType() ||
1320         DstType->isRealFloatingType())
1321       return EmitFixedPointConversion(Src, SrcType, DstType, Loc);
1322 
1323     llvm_unreachable(
1324         "Unhandled scalar conversion from a fixed point type to another type.");
1325   } else if (DstType->isFixedPointType()) {
1326     if (SrcType->isIntegerType() || SrcType->isRealFloatingType())
1327       // This also includes converting booleans and enums to fixed point types.
1328       return EmitFixedPointConversion(Src, SrcType, DstType, Loc);
1329 
1330     llvm_unreachable(
1331         "Unhandled scalar conversion to a fixed point type from another type.");
1332   }
1333 
1334   QualType NoncanonicalSrcType = SrcType;
1335   QualType NoncanonicalDstType = DstType;
1336 
1337   SrcType = CGF.getContext().getCanonicalType(SrcType);
1338   DstType = CGF.getContext().getCanonicalType(DstType);
1339   if (SrcType == DstType) return Src;
1340 
1341   if (DstType->isVoidType()) return nullptr;
1342 
1343   llvm::Value *OrigSrc = Src;
1344   QualType OrigSrcType = SrcType;
1345   llvm::Type *SrcTy = Src->getType();
1346 
1347   // Handle conversions to bool first, they are special: comparisons against 0.
1348   if (DstType->isBooleanType())
1349     return EmitConversionToBool(Src, SrcType);
1350 
1351   llvm::Type *DstTy = ConvertType(DstType);
1352 
1353   // Cast from half through float if half isn't a native type.
1354   if (SrcType->isHalfType() && !CGF.getContext().getLangOpts().NativeHalfType) {
1355     // Cast to FP using the intrinsic if the half type itself isn't supported.
1356     if (DstTy->isFloatingPointTy()) {
1357       if (CGF.getContext().getTargetInfo().useFP16ConversionIntrinsics())
1358         return Builder.CreateCall(
1359             CGF.CGM.getIntrinsic(llvm::Intrinsic::convert_from_fp16, DstTy),
1360             Src);
1361     } else {
1362       // Cast to other types through float, using either the intrinsic or FPExt,
1363       // depending on whether the half type itself is supported
1364       // (as opposed to operations on half, available with NativeHalfType).
1365       if (CGF.getContext().getTargetInfo().useFP16ConversionIntrinsics()) {
1366         Src = Builder.CreateCall(
1367             CGF.CGM.getIntrinsic(llvm::Intrinsic::convert_from_fp16,
1368                                  CGF.CGM.FloatTy),
1369             Src);
1370       } else {
1371         Src = Builder.CreateFPExt(Src, CGF.CGM.FloatTy, "conv");
1372       }
1373       SrcType = CGF.getContext().FloatTy;
1374       SrcTy = CGF.FloatTy;
1375     }
1376   }
1377 
1378   // Ignore conversions like int -> uint.
1379   if (SrcTy == DstTy) {
1380     if (Opts.EmitImplicitIntegerSignChangeChecks)
1381       EmitIntegerSignChangeCheck(Src, NoncanonicalSrcType, Src,
1382                                  NoncanonicalDstType, Loc);
1383 
1384     return Src;
1385   }
1386 
1387   // Handle pointer conversions next: pointers can only be converted to/from
1388   // other pointers and integers. Check for pointer types in terms of LLVM, as
1389   // some native types (like Obj-C id) may map to a pointer type.
1390   if (auto DstPT = dyn_cast<llvm::PointerType>(DstTy)) {
1391     // The source value may be an integer, or a pointer.
1392     if (isa<llvm::PointerType>(SrcTy))
1393       return Builder.CreateBitCast(Src, DstTy, "conv");
1394 
1395     assert(SrcType->isIntegerType() && "Not ptr->ptr or int->ptr conversion?");
1396     // First, convert to the correct width so that we control the kind of
1397     // extension.
1398     llvm::Type *MiddleTy = CGF.CGM.getDataLayout().getIntPtrType(DstPT);
1399     bool InputSigned = SrcType->isSignedIntegerOrEnumerationType();
1400     llvm::Value* IntResult =
1401         Builder.CreateIntCast(Src, MiddleTy, InputSigned, "conv");
1402     // Then, cast to pointer.
1403     return Builder.CreateIntToPtr(IntResult, DstTy, "conv");
1404   }
1405 
1406   if (isa<llvm::PointerType>(SrcTy)) {
1407     // Must be an ptr to int cast.
1408     assert(isa<llvm::IntegerType>(DstTy) && "not ptr->int?");
1409     return Builder.CreatePtrToInt(Src, DstTy, "conv");
1410   }
1411 
1412   // A scalar can be splatted to an extended vector of the same element type
1413   if (DstType->isExtVectorType() && !SrcType->isVectorType()) {
1414     // Sema should add casts to make sure that the source expression's type is
1415     // the same as the vector's element type (sans qualifiers)
1416     assert(DstType->castAs<ExtVectorType>()->getElementType().getTypePtr() ==
1417                SrcType.getTypePtr() &&
1418            "Splatted expr doesn't match with vector element type?");
1419 
1420     // Splat the element across to all elements
1421     unsigned NumElements = cast<llvm::FixedVectorType>(DstTy)->getNumElements();
1422     return Builder.CreateVectorSplat(NumElements, Src, "splat");
1423   }
1424 
1425   if (SrcType->isMatrixType() && DstType->isMatrixType())
1426     return EmitScalarCast(Src, SrcType, DstType, SrcTy, DstTy, Opts);
1427 
1428   if (isa<llvm::VectorType>(SrcTy) || isa<llvm::VectorType>(DstTy)) {
1429     // Allow bitcast from vector to integer/fp of the same size.
1430     llvm::TypeSize SrcSize = SrcTy->getPrimitiveSizeInBits();
1431     llvm::TypeSize DstSize = DstTy->getPrimitiveSizeInBits();
1432     if (SrcSize == DstSize)
1433       return Builder.CreateBitCast(Src, DstTy, "conv");
1434 
1435     // Conversions between vectors of different sizes are not allowed except
1436     // when vectors of half are involved. Operations on storage-only half
1437     // vectors require promoting half vector operands to float vectors and
1438     // truncating the result, which is either an int or float vector, to a
1439     // short or half vector.
1440 
1441     // Source and destination are both expected to be vectors.
1442     llvm::Type *SrcElementTy = cast<llvm::VectorType>(SrcTy)->getElementType();
1443     llvm::Type *DstElementTy = cast<llvm::VectorType>(DstTy)->getElementType();
1444     (void)DstElementTy;
1445 
1446     assert(((SrcElementTy->isIntegerTy() &&
1447              DstElementTy->isIntegerTy()) ||
1448             (SrcElementTy->isFloatingPointTy() &&
1449              DstElementTy->isFloatingPointTy())) &&
1450            "unexpected conversion between a floating-point vector and an "
1451            "integer vector");
1452 
1453     // Truncate an i32 vector to an i16 vector.
1454     if (SrcElementTy->isIntegerTy())
1455       return Builder.CreateIntCast(Src, DstTy, false, "conv");
1456 
1457     // Truncate a float vector to a half vector.
1458     if (SrcSize > DstSize)
1459       return Builder.CreateFPTrunc(Src, DstTy, "conv");
1460 
1461     // Promote a half vector to a float vector.
1462     return Builder.CreateFPExt(Src, DstTy, "conv");
1463   }
1464 
1465   // Finally, we have the arithmetic types: real int/float.
1466   Value *Res = nullptr;
1467   llvm::Type *ResTy = DstTy;
1468 
1469   // An overflowing conversion has undefined behavior if either the source type
1470   // or the destination type is a floating-point type. However, we consider the
1471   // range of representable values for all floating-point types to be
1472   // [-inf,+inf], so no overflow can ever happen when the destination type is a
1473   // floating-point type.
1474   if (CGF.SanOpts.has(SanitizerKind::FloatCastOverflow) &&
1475       OrigSrcType->isFloatingType())
1476     EmitFloatConversionCheck(OrigSrc, OrigSrcType, Src, SrcType, DstType, DstTy,
1477                              Loc);
1478 
1479   // Cast to half through float if half isn't a native type.
1480   if (DstType->isHalfType() && !CGF.getContext().getLangOpts().NativeHalfType) {
1481     // Make sure we cast in a single step if from another FP type.
1482     if (SrcTy->isFloatingPointTy()) {
1483       // Use the intrinsic if the half type itself isn't supported
1484       // (as opposed to operations on half, available with NativeHalfType).
1485       if (CGF.getContext().getTargetInfo().useFP16ConversionIntrinsics())
1486         return Builder.CreateCall(
1487             CGF.CGM.getIntrinsic(llvm::Intrinsic::convert_to_fp16, SrcTy), Src);
1488       // If the half type is supported, just use an fptrunc.
1489       return Builder.CreateFPTrunc(Src, DstTy);
1490     }
1491     DstTy = CGF.FloatTy;
1492   }
1493 
1494   Res = EmitScalarCast(Src, SrcType, DstType, SrcTy, DstTy, Opts);
1495 
1496   if (DstTy != ResTy) {
1497     if (CGF.getContext().getTargetInfo().useFP16ConversionIntrinsics()) {
1498       assert(ResTy->isIntegerTy(16) && "Only half FP requires extra conversion");
1499       Res = Builder.CreateCall(
1500         CGF.CGM.getIntrinsic(llvm::Intrinsic::convert_to_fp16, CGF.CGM.FloatTy),
1501         Res);
1502     } else {
1503       Res = Builder.CreateFPTrunc(Res, ResTy, "conv");
1504     }
1505   }
1506 
1507   if (Opts.EmitImplicitIntegerTruncationChecks)
1508     EmitIntegerTruncationCheck(Src, NoncanonicalSrcType, Res,
1509                                NoncanonicalDstType, Loc);
1510 
1511   if (Opts.EmitImplicitIntegerSignChangeChecks)
1512     EmitIntegerSignChangeCheck(Src, NoncanonicalSrcType, Res,
1513                                NoncanonicalDstType, Loc);
1514 
1515   return Res;
1516 }
1517 
1518 Value *ScalarExprEmitter::EmitFixedPointConversion(Value *Src, QualType SrcTy,
1519                                                    QualType DstTy,
1520                                                    SourceLocation Loc) {
1521   llvm::FixedPointBuilder<CGBuilderTy> FPBuilder(Builder);
1522   llvm::Value *Result;
1523   if (SrcTy->isRealFloatingType())
1524     Result = FPBuilder.CreateFloatingToFixed(Src,
1525         CGF.getContext().getFixedPointSemantics(DstTy));
1526   else if (DstTy->isRealFloatingType())
1527     Result = FPBuilder.CreateFixedToFloating(Src,
1528         CGF.getContext().getFixedPointSemantics(SrcTy),
1529         ConvertType(DstTy));
1530   else {
1531     auto SrcFPSema = CGF.getContext().getFixedPointSemantics(SrcTy);
1532     auto DstFPSema = CGF.getContext().getFixedPointSemantics(DstTy);
1533 
1534     if (DstTy->isIntegerType())
1535       Result = FPBuilder.CreateFixedToInteger(Src, SrcFPSema,
1536                                               DstFPSema.getWidth(),
1537                                               DstFPSema.isSigned());
1538     else if (SrcTy->isIntegerType())
1539       Result =  FPBuilder.CreateIntegerToFixed(Src, SrcFPSema.isSigned(),
1540                                                DstFPSema);
1541     else
1542       Result = FPBuilder.CreateFixedToFixed(Src, SrcFPSema, DstFPSema);
1543   }
1544   return Result;
1545 }
1546 
1547 /// Emit a conversion from the specified complex type to the specified
1548 /// destination type, where the destination type is an LLVM scalar type.
1549 Value *ScalarExprEmitter::EmitComplexToScalarConversion(
1550     CodeGenFunction::ComplexPairTy Src, QualType SrcTy, QualType DstTy,
1551     SourceLocation Loc) {
1552   // Get the source element type.
1553   SrcTy = SrcTy->castAs<ComplexType>()->getElementType();
1554 
1555   // Handle conversions to bool first, they are special: comparisons against 0.
1556   if (DstTy->isBooleanType()) {
1557     //  Complex != 0  -> (Real != 0) | (Imag != 0)
1558     Src.first = EmitScalarConversion(Src.first, SrcTy, DstTy, Loc);
1559     Src.second = EmitScalarConversion(Src.second, SrcTy, DstTy, Loc);
1560     return Builder.CreateOr(Src.first, Src.second, "tobool");
1561   }
1562 
1563   // C99 6.3.1.7p2: "When a value of complex type is converted to a real type,
1564   // the imaginary part of the complex value is discarded and the value of the
1565   // real part is converted according to the conversion rules for the
1566   // corresponding real type.
1567   return EmitScalarConversion(Src.first, SrcTy, DstTy, Loc);
1568 }
1569 
1570 Value *ScalarExprEmitter::EmitNullValue(QualType Ty) {
1571   return CGF.EmitFromMemory(CGF.CGM.EmitNullConstant(Ty), Ty);
1572 }
1573 
1574 /// Emit a sanitization check for the given "binary" operation (which
1575 /// might actually be a unary increment which has been lowered to a binary
1576 /// operation). The check passes if all values in \p Checks (which are \c i1),
1577 /// are \c true.
1578 void ScalarExprEmitter::EmitBinOpCheck(
1579     ArrayRef<std::pair<Value *, SanitizerMask>> Checks, const BinOpInfo &Info) {
1580   assert(CGF.IsSanitizerScope);
1581   SanitizerHandler Check;
1582   SmallVector<llvm::Constant *, 4> StaticData;
1583   SmallVector<llvm::Value *, 2> DynamicData;
1584 
1585   BinaryOperatorKind Opcode = Info.Opcode;
1586   if (BinaryOperator::isCompoundAssignmentOp(Opcode))
1587     Opcode = BinaryOperator::getOpForCompoundAssignment(Opcode);
1588 
1589   StaticData.push_back(CGF.EmitCheckSourceLocation(Info.E->getExprLoc()));
1590   const UnaryOperator *UO = dyn_cast<UnaryOperator>(Info.E);
1591   if (UO && UO->getOpcode() == UO_Minus) {
1592     Check = SanitizerHandler::NegateOverflow;
1593     StaticData.push_back(CGF.EmitCheckTypeDescriptor(UO->getType()));
1594     DynamicData.push_back(Info.RHS);
1595   } else {
1596     if (BinaryOperator::isShiftOp(Opcode)) {
1597       // Shift LHS negative or too large, or RHS out of bounds.
1598       Check = SanitizerHandler::ShiftOutOfBounds;
1599       const BinaryOperator *BO = cast<BinaryOperator>(Info.E);
1600       StaticData.push_back(
1601         CGF.EmitCheckTypeDescriptor(BO->getLHS()->getType()));
1602       StaticData.push_back(
1603         CGF.EmitCheckTypeDescriptor(BO->getRHS()->getType()));
1604     } else if (Opcode == BO_Div || Opcode == BO_Rem) {
1605       // Divide or modulo by zero, or signed overflow (eg INT_MAX / -1).
1606       Check = SanitizerHandler::DivremOverflow;
1607       StaticData.push_back(CGF.EmitCheckTypeDescriptor(Info.Ty));
1608     } else {
1609       // Arithmetic overflow (+, -, *).
1610       switch (Opcode) {
1611       case BO_Add: Check = SanitizerHandler::AddOverflow; break;
1612       case BO_Sub: Check = SanitizerHandler::SubOverflow; break;
1613       case BO_Mul: Check = SanitizerHandler::MulOverflow; break;
1614       default: llvm_unreachable("unexpected opcode for bin op check");
1615       }
1616       StaticData.push_back(CGF.EmitCheckTypeDescriptor(Info.Ty));
1617     }
1618     DynamicData.push_back(Info.LHS);
1619     DynamicData.push_back(Info.RHS);
1620   }
1621 
1622   CGF.EmitCheck(Checks, Check, StaticData, DynamicData);
1623 }
1624 
1625 //===----------------------------------------------------------------------===//
1626 //                            Visitor Methods
1627 //===----------------------------------------------------------------------===//
1628 
1629 Value *ScalarExprEmitter::VisitExpr(Expr *E) {
1630   CGF.ErrorUnsupported(E, "scalar expression");
1631   if (E->getType()->isVoidType())
1632     return nullptr;
1633   return llvm::UndefValue::get(CGF.ConvertType(E->getType()));
1634 }
1635 
1636 Value *
1637 ScalarExprEmitter::VisitSYCLUniqueStableNameExpr(SYCLUniqueStableNameExpr *E) {
1638   ASTContext &Context = CGF.getContext();
1639   unsigned AddrSpace =
1640       Context.getTargetAddressSpace(CGF.CGM.GetGlobalConstantAddressSpace());
1641   llvm::Constant *GlobalConstStr = Builder.CreateGlobalStringPtr(
1642       E->ComputeName(Context), "__usn_str", AddrSpace);
1643 
1644   llvm::Type *ExprTy = ConvertType(E->getType());
1645   return Builder.CreatePointerBitCastOrAddrSpaceCast(GlobalConstStr, ExprTy,
1646                                                      "usn_addr_cast");
1647 }
1648 
1649 Value *ScalarExprEmitter::VisitShuffleVectorExpr(ShuffleVectorExpr *E) {
1650   // Vector Mask Case
1651   if (E->getNumSubExprs() == 2) {
1652     Value *LHS = CGF.EmitScalarExpr(E->getExpr(0));
1653     Value *RHS = CGF.EmitScalarExpr(E->getExpr(1));
1654     Value *Mask;
1655 
1656     auto *LTy = cast<llvm::FixedVectorType>(LHS->getType());
1657     unsigned LHSElts = LTy->getNumElements();
1658 
1659     Mask = RHS;
1660 
1661     auto *MTy = cast<llvm::FixedVectorType>(Mask->getType());
1662 
1663     // Mask off the high bits of each shuffle index.
1664     Value *MaskBits =
1665         llvm::ConstantInt::get(MTy, llvm::NextPowerOf2(LHSElts - 1) - 1);
1666     Mask = Builder.CreateAnd(Mask, MaskBits, "mask");
1667 
1668     // newv = undef
1669     // mask = mask & maskbits
1670     // for each elt
1671     //   n = extract mask i
1672     //   x = extract val n
1673     //   newv = insert newv, x, i
1674     auto *RTy = llvm::FixedVectorType::get(LTy->getElementType(),
1675                                            MTy->getNumElements());
1676     Value* NewV = llvm::PoisonValue::get(RTy);
1677     for (unsigned i = 0, e = MTy->getNumElements(); i != e; ++i) {
1678       Value *IIndx = llvm::ConstantInt::get(CGF.SizeTy, i);
1679       Value *Indx = Builder.CreateExtractElement(Mask, IIndx, "shuf_idx");
1680 
1681       Value *VExt = Builder.CreateExtractElement(LHS, Indx, "shuf_elt");
1682       NewV = Builder.CreateInsertElement(NewV, VExt, IIndx, "shuf_ins");
1683     }
1684     return NewV;
1685   }
1686 
1687   Value* V1 = CGF.EmitScalarExpr(E->getExpr(0));
1688   Value* V2 = CGF.EmitScalarExpr(E->getExpr(1));
1689 
1690   SmallVector<int, 32> Indices;
1691   for (unsigned i = 2; i < E->getNumSubExprs(); ++i) {
1692     llvm::APSInt Idx = E->getShuffleMaskIdx(CGF.getContext(), i-2);
1693     // Check for -1 and output it as undef in the IR.
1694     if (Idx.isSigned() && Idx.isAllOnes())
1695       Indices.push_back(-1);
1696     else
1697       Indices.push_back(Idx.getZExtValue());
1698   }
1699 
1700   return Builder.CreateShuffleVector(V1, V2, Indices, "shuffle");
1701 }
1702 
1703 Value *ScalarExprEmitter::VisitConvertVectorExpr(ConvertVectorExpr *E) {
1704   QualType SrcType = E->getSrcExpr()->getType(),
1705            DstType = E->getType();
1706 
1707   Value *Src  = CGF.EmitScalarExpr(E->getSrcExpr());
1708 
1709   SrcType = CGF.getContext().getCanonicalType(SrcType);
1710   DstType = CGF.getContext().getCanonicalType(DstType);
1711   if (SrcType == DstType) return Src;
1712 
1713   assert(SrcType->isVectorType() &&
1714          "ConvertVector source type must be a vector");
1715   assert(DstType->isVectorType() &&
1716          "ConvertVector destination type must be a vector");
1717 
1718   llvm::Type *SrcTy = Src->getType();
1719   llvm::Type *DstTy = ConvertType(DstType);
1720 
1721   // Ignore conversions like int -> uint.
1722   if (SrcTy == DstTy)
1723     return Src;
1724 
1725   QualType SrcEltType = SrcType->castAs<VectorType>()->getElementType(),
1726            DstEltType = DstType->castAs<VectorType>()->getElementType();
1727 
1728   assert(SrcTy->isVectorTy() &&
1729          "ConvertVector source IR type must be a vector");
1730   assert(DstTy->isVectorTy() &&
1731          "ConvertVector destination IR type must be a vector");
1732 
1733   llvm::Type *SrcEltTy = cast<llvm::VectorType>(SrcTy)->getElementType(),
1734              *DstEltTy = cast<llvm::VectorType>(DstTy)->getElementType();
1735 
1736   if (DstEltType->isBooleanType()) {
1737     assert((SrcEltTy->isFloatingPointTy() ||
1738             isa<llvm::IntegerType>(SrcEltTy)) && "Unknown boolean conversion");
1739 
1740     llvm::Value *Zero = llvm::Constant::getNullValue(SrcTy);
1741     if (SrcEltTy->isFloatingPointTy()) {
1742       return Builder.CreateFCmpUNE(Src, Zero, "tobool");
1743     } else {
1744       return Builder.CreateICmpNE(Src, Zero, "tobool");
1745     }
1746   }
1747 
1748   // We have the arithmetic types: real int/float.
1749   Value *Res = nullptr;
1750 
1751   if (isa<llvm::IntegerType>(SrcEltTy)) {
1752     bool InputSigned = SrcEltType->isSignedIntegerOrEnumerationType();
1753     if (isa<llvm::IntegerType>(DstEltTy))
1754       Res = Builder.CreateIntCast(Src, DstTy, InputSigned, "conv");
1755     else if (InputSigned)
1756       Res = Builder.CreateSIToFP(Src, DstTy, "conv");
1757     else
1758       Res = Builder.CreateUIToFP(Src, DstTy, "conv");
1759   } else if (isa<llvm::IntegerType>(DstEltTy)) {
1760     assert(SrcEltTy->isFloatingPointTy() && "Unknown real conversion");
1761     if (DstEltType->isSignedIntegerOrEnumerationType())
1762       Res = Builder.CreateFPToSI(Src, DstTy, "conv");
1763     else
1764       Res = Builder.CreateFPToUI(Src, DstTy, "conv");
1765   } else {
1766     assert(SrcEltTy->isFloatingPointTy() && DstEltTy->isFloatingPointTy() &&
1767            "Unknown real conversion");
1768     if (DstEltTy->getTypeID() < SrcEltTy->getTypeID())
1769       Res = Builder.CreateFPTrunc(Src, DstTy, "conv");
1770     else
1771       Res = Builder.CreateFPExt(Src, DstTy, "conv");
1772   }
1773 
1774   return Res;
1775 }
1776 
1777 Value *ScalarExprEmitter::VisitMemberExpr(MemberExpr *E) {
1778   if (CodeGenFunction::ConstantEmission Constant = CGF.tryEmitAsConstant(E)) {
1779     CGF.EmitIgnoredExpr(E->getBase());
1780     return CGF.emitScalarConstant(Constant, E);
1781   } else {
1782     Expr::EvalResult Result;
1783     if (E->EvaluateAsInt(Result, CGF.getContext(), Expr::SE_AllowSideEffects)) {
1784       llvm::APSInt Value = Result.Val.getInt();
1785       CGF.EmitIgnoredExpr(E->getBase());
1786       return Builder.getInt(Value);
1787     }
1788   }
1789 
1790   return EmitLoadOfLValue(E);
1791 }
1792 
1793 Value *ScalarExprEmitter::VisitArraySubscriptExpr(ArraySubscriptExpr *E) {
1794   TestAndClearIgnoreResultAssign();
1795 
1796   // Emit subscript expressions in rvalue context's.  For most cases, this just
1797   // loads the lvalue formed by the subscript expr.  However, we have to be
1798   // careful, because the base of a vector subscript is occasionally an rvalue,
1799   // so we can't get it as an lvalue.
1800   if (!E->getBase()->getType()->isVectorType() &&
1801       !E->getBase()->getType()->isSveVLSBuiltinType())
1802     return EmitLoadOfLValue(E);
1803 
1804   // Handle the vector case.  The base must be a vector, the index must be an
1805   // integer value.
1806   Value *Base = Visit(E->getBase());
1807   Value *Idx  = Visit(E->getIdx());
1808   QualType IdxTy = E->getIdx()->getType();
1809 
1810   if (CGF.SanOpts.has(SanitizerKind::ArrayBounds))
1811     CGF.EmitBoundsCheck(E, E->getBase(), Idx, IdxTy, /*Accessed*/true);
1812 
1813   return Builder.CreateExtractElement(Base, Idx, "vecext");
1814 }
1815 
1816 Value *ScalarExprEmitter::VisitMatrixSubscriptExpr(MatrixSubscriptExpr *E) {
1817   TestAndClearIgnoreResultAssign();
1818 
1819   // Handle the vector case.  The base must be a vector, the index must be an
1820   // integer value.
1821   Value *RowIdx = Visit(E->getRowIdx());
1822   Value *ColumnIdx = Visit(E->getColumnIdx());
1823 
1824   const auto *MatrixTy = E->getBase()->getType()->castAs<ConstantMatrixType>();
1825   unsigned NumRows = MatrixTy->getNumRows();
1826   llvm::MatrixBuilder MB(Builder);
1827   Value *Idx = MB.CreateIndex(RowIdx, ColumnIdx, NumRows);
1828   if (CGF.CGM.getCodeGenOpts().OptimizationLevel > 0)
1829     MB.CreateIndexAssumption(Idx, MatrixTy->getNumElementsFlattened());
1830 
1831   Value *Matrix = Visit(E->getBase());
1832 
1833   // TODO: Should we emit bounds checks with SanitizerKind::ArrayBounds?
1834   return Builder.CreateExtractElement(Matrix, Idx, "matrixext");
1835 }
1836 
1837 static int getMaskElt(llvm::ShuffleVectorInst *SVI, unsigned Idx,
1838                       unsigned Off) {
1839   int MV = SVI->getMaskValue(Idx);
1840   if (MV == -1)
1841     return -1;
1842   return Off + MV;
1843 }
1844 
1845 static int getAsInt32(llvm::ConstantInt *C, llvm::Type *I32Ty) {
1846   assert(llvm::ConstantInt::isValueValidForType(I32Ty, C->getZExtValue()) &&
1847          "Index operand too large for shufflevector mask!");
1848   return C->getZExtValue();
1849 }
1850 
1851 Value *ScalarExprEmitter::VisitInitListExpr(InitListExpr *E) {
1852   bool Ignore = TestAndClearIgnoreResultAssign();
1853   (void)Ignore;
1854   assert (Ignore == false && "init list ignored");
1855   unsigned NumInitElements = E->getNumInits();
1856 
1857   if (E->hadArrayRangeDesignator())
1858     CGF.ErrorUnsupported(E, "GNU array range designator extension");
1859 
1860   llvm::VectorType *VType =
1861     dyn_cast<llvm::VectorType>(ConvertType(E->getType()));
1862 
1863   if (!VType) {
1864     if (NumInitElements == 0) {
1865       // C++11 value-initialization for the scalar.
1866       return EmitNullValue(E->getType());
1867     }
1868     // We have a scalar in braces. Just use the first element.
1869     return Visit(E->getInit(0));
1870   }
1871 
1872   if (isa<llvm::ScalableVectorType>(VType)) {
1873     if (NumInitElements == 0) {
1874       // C++11 value-initialization for the vector.
1875       return EmitNullValue(E->getType());
1876     }
1877 
1878     if (NumInitElements == 1) {
1879       Expr *InitVector = E->getInit(0);
1880 
1881       // Initialize from another scalable vector of the same type.
1882       if (InitVector->getType() == E->getType())
1883         return Visit(InitVector);
1884     }
1885 
1886     llvm_unreachable("Unexpected initialization of a scalable vector!");
1887   }
1888 
1889   unsigned ResElts = cast<llvm::FixedVectorType>(VType)->getNumElements();
1890 
1891   // Loop over initializers collecting the Value for each, and remembering
1892   // whether the source was swizzle (ExtVectorElementExpr).  This will allow
1893   // us to fold the shuffle for the swizzle into the shuffle for the vector
1894   // initializer, since LLVM optimizers generally do not want to touch
1895   // shuffles.
1896   unsigned CurIdx = 0;
1897   bool VIsPoisonShuffle = false;
1898   llvm::Value *V = llvm::PoisonValue::get(VType);
1899   for (unsigned i = 0; i != NumInitElements; ++i) {
1900     Expr *IE = E->getInit(i);
1901     Value *Init = Visit(IE);
1902     SmallVector<int, 16> Args;
1903 
1904     llvm::VectorType *VVT = dyn_cast<llvm::VectorType>(Init->getType());
1905 
1906     // Handle scalar elements.  If the scalar initializer is actually one
1907     // element of a different vector of the same width, use shuffle instead of
1908     // extract+insert.
1909     if (!VVT) {
1910       if (isa<ExtVectorElementExpr>(IE)) {
1911         llvm::ExtractElementInst *EI = cast<llvm::ExtractElementInst>(Init);
1912 
1913         if (cast<llvm::FixedVectorType>(EI->getVectorOperandType())
1914                 ->getNumElements() == ResElts) {
1915           llvm::ConstantInt *C = cast<llvm::ConstantInt>(EI->getIndexOperand());
1916           Value *LHS = nullptr, *RHS = nullptr;
1917           if (CurIdx == 0) {
1918             // insert into poison -> shuffle (src, poison)
1919             // shufflemask must use an i32
1920             Args.push_back(getAsInt32(C, CGF.Int32Ty));
1921             Args.resize(ResElts, -1);
1922 
1923             LHS = EI->getVectorOperand();
1924             RHS = V;
1925             VIsPoisonShuffle = true;
1926           } else if (VIsPoisonShuffle) {
1927             // insert into poison shuffle && size match -> shuffle (v, src)
1928             llvm::ShuffleVectorInst *SVV = cast<llvm::ShuffleVectorInst>(V);
1929             for (unsigned j = 0; j != CurIdx; ++j)
1930               Args.push_back(getMaskElt(SVV, j, 0));
1931             Args.push_back(ResElts + C->getZExtValue());
1932             Args.resize(ResElts, -1);
1933 
1934             LHS = cast<llvm::ShuffleVectorInst>(V)->getOperand(0);
1935             RHS = EI->getVectorOperand();
1936             VIsPoisonShuffle = false;
1937           }
1938           if (!Args.empty()) {
1939             V = Builder.CreateShuffleVector(LHS, RHS, Args);
1940             ++CurIdx;
1941             continue;
1942           }
1943         }
1944       }
1945       V = Builder.CreateInsertElement(V, Init, Builder.getInt32(CurIdx),
1946                                       "vecinit");
1947       VIsPoisonShuffle = false;
1948       ++CurIdx;
1949       continue;
1950     }
1951 
1952     unsigned InitElts = cast<llvm::FixedVectorType>(VVT)->getNumElements();
1953 
1954     // If the initializer is an ExtVecEltExpr (a swizzle), and the swizzle's
1955     // input is the same width as the vector being constructed, generate an
1956     // optimized shuffle of the swizzle input into the result.
1957     unsigned Offset = (CurIdx == 0) ? 0 : ResElts;
1958     if (isa<ExtVectorElementExpr>(IE)) {
1959       llvm::ShuffleVectorInst *SVI = cast<llvm::ShuffleVectorInst>(Init);
1960       Value *SVOp = SVI->getOperand(0);
1961       auto *OpTy = cast<llvm::FixedVectorType>(SVOp->getType());
1962 
1963       if (OpTy->getNumElements() == ResElts) {
1964         for (unsigned j = 0; j != CurIdx; ++j) {
1965           // If the current vector initializer is a shuffle with poison, merge
1966           // this shuffle directly into it.
1967           if (VIsPoisonShuffle) {
1968             Args.push_back(getMaskElt(cast<llvm::ShuffleVectorInst>(V), j, 0));
1969           } else {
1970             Args.push_back(j);
1971           }
1972         }
1973         for (unsigned j = 0, je = InitElts; j != je; ++j)
1974           Args.push_back(getMaskElt(SVI, j, Offset));
1975         Args.resize(ResElts, -1);
1976 
1977         if (VIsPoisonShuffle)
1978           V = cast<llvm::ShuffleVectorInst>(V)->getOperand(0);
1979 
1980         Init = SVOp;
1981       }
1982     }
1983 
1984     // Extend init to result vector length, and then shuffle its contribution
1985     // to the vector initializer into V.
1986     if (Args.empty()) {
1987       for (unsigned j = 0; j != InitElts; ++j)
1988         Args.push_back(j);
1989       Args.resize(ResElts, -1);
1990       Init = Builder.CreateShuffleVector(Init, Args, "vext");
1991 
1992       Args.clear();
1993       for (unsigned j = 0; j != CurIdx; ++j)
1994         Args.push_back(j);
1995       for (unsigned j = 0; j != InitElts; ++j)
1996         Args.push_back(j + Offset);
1997       Args.resize(ResElts, -1);
1998     }
1999 
2000     // If V is poison, make sure it ends up on the RHS of the shuffle to aid
2001     // merging subsequent shuffles into this one.
2002     if (CurIdx == 0)
2003       std::swap(V, Init);
2004     V = Builder.CreateShuffleVector(V, Init, Args, "vecinit");
2005     VIsPoisonShuffle = isa<llvm::PoisonValue>(Init);
2006     CurIdx += InitElts;
2007   }
2008 
2009   // FIXME: evaluate codegen vs. shuffling against constant null vector.
2010   // Emit remaining default initializers.
2011   llvm::Type *EltTy = VType->getElementType();
2012 
2013   // Emit remaining default initializers
2014   for (/* Do not initialize i*/; CurIdx < ResElts; ++CurIdx) {
2015     Value *Idx = Builder.getInt32(CurIdx);
2016     llvm::Value *Init = llvm::Constant::getNullValue(EltTy);
2017     V = Builder.CreateInsertElement(V, Init, Idx, "vecinit");
2018   }
2019   return V;
2020 }
2021 
2022 bool CodeGenFunction::ShouldNullCheckClassCastValue(const CastExpr *CE) {
2023   const Expr *E = CE->getSubExpr();
2024 
2025   if (CE->getCastKind() == CK_UncheckedDerivedToBase)
2026     return false;
2027 
2028   if (isa<CXXThisExpr>(E->IgnoreParens())) {
2029     // We always assume that 'this' is never null.
2030     return false;
2031   }
2032 
2033   if (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(CE)) {
2034     // And that glvalue casts are never null.
2035     if (ICE->isGLValue())
2036       return false;
2037   }
2038 
2039   return true;
2040 }
2041 
2042 // VisitCastExpr - Emit code for an explicit or implicit cast.  Implicit casts
2043 // have to handle a more broad range of conversions than explicit casts, as they
2044 // handle things like function to ptr-to-function decay etc.
2045 Value *ScalarExprEmitter::VisitCastExpr(CastExpr *CE) {
2046   Expr *E = CE->getSubExpr();
2047   QualType DestTy = CE->getType();
2048   CastKind Kind = CE->getCastKind();
2049   CodeGenFunction::CGFPOptionsRAII FPOptions(CGF, CE);
2050 
2051   // These cases are generally not written to ignore the result of
2052   // evaluating their sub-expressions, so we clear this now.
2053   bool Ignored = TestAndClearIgnoreResultAssign();
2054 
2055   // Since almost all cast kinds apply to scalars, this switch doesn't have
2056   // a default case, so the compiler will warn on a missing case.  The cases
2057   // are in the same order as in the CastKind enum.
2058   switch (Kind) {
2059   case CK_Dependent: llvm_unreachable("dependent cast kind in IR gen!");
2060   case CK_BuiltinFnToFnPtr:
2061     llvm_unreachable("builtin functions are handled elsewhere");
2062 
2063   case CK_LValueBitCast:
2064   case CK_ObjCObjectLValueCast: {
2065     Address Addr = EmitLValue(E).getAddress(CGF);
2066     Addr = Addr.withElementType(CGF.ConvertTypeForMem(DestTy));
2067     LValue LV = CGF.MakeAddrLValue(Addr, DestTy);
2068     return EmitLoadOfLValue(LV, CE->getExprLoc());
2069   }
2070 
2071   case CK_LValueToRValueBitCast: {
2072     LValue SourceLVal = CGF.EmitLValue(E);
2073     Address Addr = SourceLVal.getAddress(CGF).withElementType(
2074         CGF.ConvertTypeForMem(DestTy));
2075     LValue DestLV = CGF.MakeAddrLValue(Addr, DestTy);
2076     DestLV.setTBAAInfo(TBAAAccessInfo::getMayAliasInfo());
2077     return EmitLoadOfLValue(DestLV, CE->getExprLoc());
2078   }
2079 
2080   case CK_CPointerToObjCPointerCast:
2081   case CK_BlockPointerToObjCPointerCast:
2082   case CK_AnyPointerToBlockPointerCast:
2083   case CK_BitCast: {
2084     Value *Src = Visit(const_cast<Expr*>(E));
2085     llvm::Type *SrcTy = Src->getType();
2086     llvm::Type *DstTy = ConvertType(DestTy);
2087     assert(
2088         (!SrcTy->isPtrOrPtrVectorTy() || !DstTy->isPtrOrPtrVectorTy() ||
2089          SrcTy->getPointerAddressSpace() == DstTy->getPointerAddressSpace()) &&
2090         "Address-space cast must be used to convert address spaces");
2091 
2092     if (CGF.SanOpts.has(SanitizerKind::CFIUnrelatedCast)) {
2093       if (auto *PT = DestTy->getAs<PointerType>()) {
2094         CGF.EmitVTablePtrCheckForCast(
2095             PT->getPointeeType(),
2096             Address(Src,
2097                     CGF.ConvertTypeForMem(
2098                         E->getType()->castAs<PointerType>()->getPointeeType()),
2099                     CGF.getPointerAlign()),
2100             /*MayBeNull=*/true, CodeGenFunction::CFITCK_UnrelatedCast,
2101             CE->getBeginLoc());
2102       }
2103     }
2104 
2105     if (CGF.CGM.getCodeGenOpts().StrictVTablePointers) {
2106       const QualType SrcType = E->getType();
2107 
2108       if (SrcType.mayBeNotDynamicClass() && DestTy.mayBeDynamicClass()) {
2109         // Casting to pointer that could carry dynamic information (provided by
2110         // invariant.group) requires launder.
2111         Src = Builder.CreateLaunderInvariantGroup(Src);
2112       } else if (SrcType.mayBeDynamicClass() && DestTy.mayBeNotDynamicClass()) {
2113         // Casting to pointer that does not carry dynamic information (provided
2114         // by invariant.group) requires stripping it.  Note that we don't do it
2115         // if the source could not be dynamic type and destination could be
2116         // dynamic because dynamic information is already laundered.  It is
2117         // because launder(strip(src)) == launder(src), so there is no need to
2118         // add extra strip before launder.
2119         Src = Builder.CreateStripInvariantGroup(Src);
2120       }
2121     }
2122 
2123     // Update heapallocsite metadata when there is an explicit pointer cast.
2124     if (auto *CI = dyn_cast<llvm::CallBase>(Src)) {
2125       if (CI->getMetadata("heapallocsite") && isa<ExplicitCastExpr>(CE) &&
2126           !isa<CastExpr>(E)) {
2127         QualType PointeeType = DestTy->getPointeeType();
2128         if (!PointeeType.isNull())
2129           CGF.getDebugInfo()->addHeapAllocSiteMetadata(CI, PointeeType,
2130                                                        CE->getExprLoc());
2131       }
2132     }
2133 
2134     // If Src is a fixed vector and Dst is a scalable vector, and both have the
2135     // same element type, use the llvm.vector.insert intrinsic to perform the
2136     // bitcast.
2137     if (const auto *FixedSrc = dyn_cast<llvm::FixedVectorType>(SrcTy)) {
2138       if (const auto *ScalableDst = dyn_cast<llvm::ScalableVectorType>(DstTy)) {
2139         // If we are casting a fixed i8 vector to a scalable 16 x i1 predicate
2140         // vector, use a vector insert and bitcast the result.
2141         bool NeedsBitCast = false;
2142         auto PredType = llvm::ScalableVectorType::get(Builder.getInt1Ty(), 16);
2143         llvm::Type *OrigType = DstTy;
2144         if (ScalableDst == PredType &&
2145             FixedSrc->getElementType() == Builder.getInt8Ty()) {
2146           DstTy = llvm::ScalableVectorType::get(Builder.getInt8Ty(), 2);
2147           ScalableDst = cast<llvm::ScalableVectorType>(DstTy);
2148           NeedsBitCast = true;
2149         }
2150         if (FixedSrc->getElementType() == ScalableDst->getElementType()) {
2151           llvm::Value *UndefVec = llvm::UndefValue::get(DstTy);
2152           llvm::Value *Zero = llvm::Constant::getNullValue(CGF.CGM.Int64Ty);
2153           llvm::Value *Result = Builder.CreateInsertVector(
2154               DstTy, UndefVec, Src, Zero, "cast.scalable");
2155           if (NeedsBitCast)
2156             Result = Builder.CreateBitCast(Result, OrigType);
2157           return Result;
2158         }
2159       }
2160     }
2161 
2162     // If Src is a scalable vector and Dst is a fixed vector, and both have the
2163     // same element type, use the llvm.vector.extract intrinsic to perform the
2164     // bitcast.
2165     if (const auto *ScalableSrc = dyn_cast<llvm::ScalableVectorType>(SrcTy)) {
2166       if (const auto *FixedDst = dyn_cast<llvm::FixedVectorType>(DstTy)) {
2167         // If we are casting a scalable 16 x i1 predicate vector to a fixed i8
2168         // vector, bitcast the source and use a vector extract.
2169         auto PredType = llvm::ScalableVectorType::get(Builder.getInt1Ty(), 16);
2170         if (ScalableSrc == PredType &&
2171             FixedDst->getElementType() == Builder.getInt8Ty()) {
2172           SrcTy = llvm::ScalableVectorType::get(Builder.getInt8Ty(), 2);
2173           ScalableSrc = cast<llvm::ScalableVectorType>(SrcTy);
2174           Src = Builder.CreateBitCast(Src, SrcTy);
2175         }
2176         if (ScalableSrc->getElementType() == FixedDst->getElementType()) {
2177           llvm::Value *Zero = llvm::Constant::getNullValue(CGF.CGM.Int64Ty);
2178           return Builder.CreateExtractVector(DstTy, Src, Zero, "cast.fixed");
2179         }
2180       }
2181     }
2182 
2183     // Perform VLAT <-> VLST bitcast through memory.
2184     // TODO: since the llvm.experimental.vector.{insert,extract} intrinsics
2185     //       require the element types of the vectors to be the same, we
2186     //       need to keep this around for bitcasts between VLAT <-> VLST where
2187     //       the element types of the vectors are not the same, until we figure
2188     //       out a better way of doing these casts.
2189     if ((isa<llvm::FixedVectorType>(SrcTy) &&
2190          isa<llvm::ScalableVectorType>(DstTy)) ||
2191         (isa<llvm::ScalableVectorType>(SrcTy) &&
2192          isa<llvm::FixedVectorType>(DstTy))) {
2193       Address Addr = CGF.CreateDefaultAlignTempAlloca(SrcTy, "saved-value");
2194       LValue LV = CGF.MakeAddrLValue(Addr, E->getType());
2195       CGF.EmitStoreOfScalar(Src, LV);
2196       Addr = Addr.withElementType(CGF.ConvertTypeForMem(DestTy));
2197       LValue DestLV = CGF.MakeAddrLValue(Addr, DestTy);
2198       DestLV.setTBAAInfo(TBAAAccessInfo::getMayAliasInfo());
2199       return EmitLoadOfLValue(DestLV, CE->getExprLoc());
2200     }
2201     return Builder.CreateBitCast(Src, DstTy);
2202   }
2203   case CK_AddressSpaceConversion: {
2204     Expr::EvalResult Result;
2205     if (E->EvaluateAsRValue(Result, CGF.getContext()) &&
2206         Result.Val.isNullPointer()) {
2207       // If E has side effect, it is emitted even if its final result is a
2208       // null pointer. In that case, a DCE pass should be able to
2209       // eliminate the useless instructions emitted during translating E.
2210       if (Result.HasSideEffects)
2211         Visit(E);
2212       return CGF.CGM.getNullPointer(cast<llvm::PointerType>(
2213           ConvertType(DestTy)), DestTy);
2214     }
2215     // Since target may map different address spaces in AST to the same address
2216     // space, an address space conversion may end up as a bitcast.
2217     return CGF.CGM.getTargetCodeGenInfo().performAddrSpaceCast(
2218         CGF, Visit(E), E->getType()->getPointeeType().getAddressSpace(),
2219         DestTy->getPointeeType().getAddressSpace(), ConvertType(DestTy));
2220   }
2221   case CK_AtomicToNonAtomic:
2222   case CK_NonAtomicToAtomic:
2223   case CK_UserDefinedConversion:
2224     return Visit(const_cast<Expr*>(E));
2225 
2226   case CK_NoOp: {
2227     return CE->changesVolatileQualification() ? EmitLoadOfLValue(CE)
2228                                               : Visit(const_cast<Expr *>(E));
2229   }
2230 
2231   case CK_BaseToDerived: {
2232     const CXXRecordDecl *DerivedClassDecl = DestTy->getPointeeCXXRecordDecl();
2233     assert(DerivedClassDecl && "BaseToDerived arg isn't a C++ object pointer!");
2234 
2235     Address Base = CGF.EmitPointerWithAlignment(E);
2236     Address Derived =
2237       CGF.GetAddressOfDerivedClass(Base, DerivedClassDecl,
2238                                    CE->path_begin(), CE->path_end(),
2239                                    CGF.ShouldNullCheckClassCastValue(CE));
2240 
2241     // C++11 [expr.static.cast]p11: Behavior is undefined if a downcast is
2242     // performed and the object is not of the derived type.
2243     if (CGF.sanitizePerformTypeCheck())
2244       CGF.EmitTypeCheck(CodeGenFunction::TCK_DowncastPointer, CE->getExprLoc(),
2245                         Derived.getPointer(), DestTy->getPointeeType());
2246 
2247     if (CGF.SanOpts.has(SanitizerKind::CFIDerivedCast))
2248       CGF.EmitVTablePtrCheckForCast(DestTy->getPointeeType(), Derived,
2249                                     /*MayBeNull=*/true,
2250                                     CodeGenFunction::CFITCK_DerivedCast,
2251                                     CE->getBeginLoc());
2252 
2253     return Derived.getPointer();
2254   }
2255   case CK_UncheckedDerivedToBase:
2256   case CK_DerivedToBase: {
2257     // The EmitPointerWithAlignment path does this fine; just discard
2258     // the alignment.
2259     return CGF.EmitPointerWithAlignment(CE).getPointer();
2260   }
2261 
2262   case CK_Dynamic: {
2263     Address V = CGF.EmitPointerWithAlignment(E);
2264     const CXXDynamicCastExpr *DCE = cast<CXXDynamicCastExpr>(CE);
2265     return CGF.EmitDynamicCast(V, DCE);
2266   }
2267 
2268   case CK_ArrayToPointerDecay:
2269     return CGF.EmitArrayToPointerDecay(E).getPointer();
2270   case CK_FunctionToPointerDecay:
2271     return EmitLValue(E).getPointer(CGF);
2272 
2273   case CK_NullToPointer:
2274     if (MustVisitNullValue(E))
2275       CGF.EmitIgnoredExpr(E);
2276 
2277     return CGF.CGM.getNullPointer(cast<llvm::PointerType>(ConvertType(DestTy)),
2278                               DestTy);
2279 
2280   case CK_NullToMemberPointer: {
2281     if (MustVisitNullValue(E))
2282       CGF.EmitIgnoredExpr(E);
2283 
2284     const MemberPointerType *MPT = CE->getType()->getAs<MemberPointerType>();
2285     return CGF.CGM.getCXXABI().EmitNullMemberPointer(MPT);
2286   }
2287 
2288   case CK_ReinterpretMemberPointer:
2289   case CK_BaseToDerivedMemberPointer:
2290   case CK_DerivedToBaseMemberPointer: {
2291     Value *Src = Visit(E);
2292 
2293     // Note that the AST doesn't distinguish between checked and
2294     // unchecked member pointer conversions, so we always have to
2295     // implement checked conversions here.  This is inefficient when
2296     // actual control flow may be required in order to perform the
2297     // check, which it is for data member pointers (but not member
2298     // function pointers on Itanium and ARM).
2299     return CGF.CGM.getCXXABI().EmitMemberPointerConversion(CGF, CE, Src);
2300   }
2301 
2302   case CK_ARCProduceObject:
2303     return CGF.EmitARCRetainScalarExpr(E);
2304   case CK_ARCConsumeObject:
2305     return CGF.EmitObjCConsumeObject(E->getType(), Visit(E));
2306   case CK_ARCReclaimReturnedObject:
2307     return CGF.EmitARCReclaimReturnedObject(E, /*allowUnsafe*/ Ignored);
2308   case CK_ARCExtendBlockObject:
2309     return CGF.EmitARCExtendBlockObject(E);
2310 
2311   case CK_CopyAndAutoreleaseBlockObject:
2312     return CGF.EmitBlockCopyAndAutorelease(Visit(E), E->getType());
2313 
2314   case CK_FloatingRealToComplex:
2315   case CK_FloatingComplexCast:
2316   case CK_IntegralRealToComplex:
2317   case CK_IntegralComplexCast:
2318   case CK_IntegralComplexToFloatingComplex:
2319   case CK_FloatingComplexToIntegralComplex:
2320   case CK_ConstructorConversion:
2321   case CK_ToUnion:
2322     llvm_unreachable("scalar cast to non-scalar value");
2323 
2324   case CK_LValueToRValue:
2325     assert(CGF.getContext().hasSameUnqualifiedType(E->getType(), DestTy));
2326     assert(E->isGLValue() && "lvalue-to-rvalue applied to r-value!");
2327     return Visit(const_cast<Expr*>(E));
2328 
2329   case CK_IntegralToPointer: {
2330     Value *Src = Visit(const_cast<Expr*>(E));
2331 
2332     // First, convert to the correct width so that we control the kind of
2333     // extension.
2334     auto DestLLVMTy = ConvertType(DestTy);
2335     llvm::Type *MiddleTy = CGF.CGM.getDataLayout().getIntPtrType(DestLLVMTy);
2336     bool InputSigned = E->getType()->isSignedIntegerOrEnumerationType();
2337     llvm::Value* IntResult =
2338       Builder.CreateIntCast(Src, MiddleTy, InputSigned, "conv");
2339 
2340     auto *IntToPtr = Builder.CreateIntToPtr(IntResult, DestLLVMTy);
2341 
2342     if (CGF.CGM.getCodeGenOpts().StrictVTablePointers) {
2343       // Going from integer to pointer that could be dynamic requires reloading
2344       // dynamic information from invariant.group.
2345       if (DestTy.mayBeDynamicClass())
2346         IntToPtr = Builder.CreateLaunderInvariantGroup(IntToPtr);
2347     }
2348     return IntToPtr;
2349   }
2350   case CK_PointerToIntegral: {
2351     assert(!DestTy->isBooleanType() && "bool should use PointerToBool");
2352     auto *PtrExpr = Visit(E);
2353 
2354     if (CGF.CGM.getCodeGenOpts().StrictVTablePointers) {
2355       const QualType SrcType = E->getType();
2356 
2357       // Casting to integer requires stripping dynamic information as it does
2358       // not carries it.
2359       if (SrcType.mayBeDynamicClass())
2360         PtrExpr = Builder.CreateStripInvariantGroup(PtrExpr);
2361     }
2362 
2363     return Builder.CreatePtrToInt(PtrExpr, ConvertType(DestTy));
2364   }
2365   case CK_ToVoid: {
2366     CGF.EmitIgnoredExpr(E);
2367     return nullptr;
2368   }
2369   case CK_MatrixCast: {
2370     return EmitScalarConversion(Visit(E), E->getType(), DestTy,
2371                                 CE->getExprLoc());
2372   }
2373   case CK_VectorSplat: {
2374     llvm::Type *DstTy = ConvertType(DestTy);
2375     Value *Elt = Visit(const_cast<Expr *>(E));
2376     // Splat the element across to all elements
2377     llvm::ElementCount NumElements =
2378         cast<llvm::VectorType>(DstTy)->getElementCount();
2379     return Builder.CreateVectorSplat(NumElements, Elt, "splat");
2380   }
2381 
2382   case CK_FixedPointCast:
2383     return EmitScalarConversion(Visit(E), E->getType(), DestTy,
2384                                 CE->getExprLoc());
2385 
2386   case CK_FixedPointToBoolean:
2387     assert(E->getType()->isFixedPointType() &&
2388            "Expected src type to be fixed point type");
2389     assert(DestTy->isBooleanType() && "Expected dest type to be boolean type");
2390     return EmitScalarConversion(Visit(E), E->getType(), DestTy,
2391                                 CE->getExprLoc());
2392 
2393   case CK_FixedPointToIntegral:
2394     assert(E->getType()->isFixedPointType() &&
2395            "Expected src type to be fixed point type");
2396     assert(DestTy->isIntegerType() && "Expected dest type to be an integer");
2397     return EmitScalarConversion(Visit(E), E->getType(), DestTy,
2398                                 CE->getExprLoc());
2399 
2400   case CK_IntegralToFixedPoint:
2401     assert(E->getType()->isIntegerType() &&
2402            "Expected src type to be an integer");
2403     assert(DestTy->isFixedPointType() &&
2404            "Expected dest type to be fixed point type");
2405     return EmitScalarConversion(Visit(E), E->getType(), DestTy,
2406                                 CE->getExprLoc());
2407 
2408   case CK_IntegralCast: {
2409     ScalarConversionOpts Opts;
2410     if (auto *ICE = dyn_cast<ImplicitCastExpr>(CE)) {
2411       if (!ICE->isPartOfExplicitCast())
2412         Opts = ScalarConversionOpts(CGF.SanOpts);
2413     }
2414     return EmitScalarConversion(Visit(E), E->getType(), DestTy,
2415                                 CE->getExprLoc(), Opts);
2416   }
2417   case CK_IntegralToFloating:
2418   case CK_FloatingToIntegral:
2419   case CK_FloatingCast:
2420   case CK_FixedPointToFloating:
2421   case CK_FloatingToFixedPoint: {
2422     CodeGenFunction::CGFPOptionsRAII FPOptsRAII(CGF, CE);
2423     return EmitScalarConversion(Visit(E), E->getType(), DestTy,
2424                                 CE->getExprLoc());
2425   }
2426   case CK_BooleanToSignedIntegral: {
2427     ScalarConversionOpts Opts;
2428     Opts.TreatBooleanAsSigned = true;
2429     return EmitScalarConversion(Visit(E), E->getType(), DestTy,
2430                                 CE->getExprLoc(), Opts);
2431   }
2432   case CK_IntegralToBoolean:
2433     return EmitIntToBoolConversion(Visit(E));
2434   case CK_PointerToBoolean:
2435     return EmitPointerToBoolConversion(Visit(E), E->getType());
2436   case CK_FloatingToBoolean: {
2437     CodeGenFunction::CGFPOptionsRAII FPOptsRAII(CGF, CE);
2438     return EmitFloatToBoolConversion(Visit(E));
2439   }
2440   case CK_MemberPointerToBoolean: {
2441     llvm::Value *MemPtr = Visit(E);
2442     const MemberPointerType *MPT = E->getType()->getAs<MemberPointerType>();
2443     return CGF.CGM.getCXXABI().EmitMemberPointerIsNotNull(CGF, MemPtr, MPT);
2444   }
2445 
2446   case CK_FloatingComplexToReal:
2447   case CK_IntegralComplexToReal:
2448     return CGF.EmitComplexExpr(E, false, true).first;
2449 
2450   case CK_FloatingComplexToBoolean:
2451   case CK_IntegralComplexToBoolean: {
2452     CodeGenFunction::ComplexPairTy V = CGF.EmitComplexExpr(E);
2453 
2454     // TODO: kill this function off, inline appropriate case here
2455     return EmitComplexToScalarConversion(V, E->getType(), DestTy,
2456                                          CE->getExprLoc());
2457   }
2458 
2459   case CK_ZeroToOCLOpaqueType: {
2460     assert((DestTy->isEventT() || DestTy->isQueueT() ||
2461             DestTy->isOCLIntelSubgroupAVCType()) &&
2462            "CK_ZeroToOCLEvent cast on non-event type");
2463     return llvm::Constant::getNullValue(ConvertType(DestTy));
2464   }
2465 
2466   case CK_IntToOCLSampler:
2467     return CGF.CGM.createOpenCLIntToSamplerConversion(E, CGF);
2468 
2469   } // end of switch
2470 
2471   llvm_unreachable("unknown scalar cast");
2472 }
2473 
2474 Value *ScalarExprEmitter::VisitStmtExpr(const StmtExpr *E) {
2475   CodeGenFunction::StmtExprEvaluation eval(CGF);
2476   Address RetAlloca = CGF.EmitCompoundStmt(*E->getSubStmt(),
2477                                            !E->getType()->isVoidType());
2478   if (!RetAlloca.isValid())
2479     return nullptr;
2480   return CGF.EmitLoadOfScalar(CGF.MakeAddrLValue(RetAlloca, E->getType()),
2481                               E->getExprLoc());
2482 }
2483 
2484 Value *ScalarExprEmitter::VisitExprWithCleanups(ExprWithCleanups *E) {
2485   CodeGenFunction::RunCleanupsScope Scope(CGF);
2486   Value *V = Visit(E->getSubExpr());
2487   // Defend against dominance problems caused by jumps out of expression
2488   // evaluation through the shared cleanup block.
2489   Scope.ForceCleanup({&V});
2490   return V;
2491 }
2492 
2493 //===----------------------------------------------------------------------===//
2494 //                             Unary Operators
2495 //===----------------------------------------------------------------------===//
2496 
2497 static BinOpInfo createBinOpInfoFromIncDec(const UnaryOperator *E,
2498                                            llvm::Value *InVal, bool IsInc,
2499                                            FPOptions FPFeatures) {
2500   BinOpInfo BinOp;
2501   BinOp.LHS = InVal;
2502   BinOp.RHS = llvm::ConstantInt::get(InVal->getType(), 1, false);
2503   BinOp.Ty = E->getType();
2504   BinOp.Opcode = IsInc ? BO_Add : BO_Sub;
2505   BinOp.FPFeatures = FPFeatures;
2506   BinOp.E = E;
2507   return BinOp;
2508 }
2509 
2510 llvm::Value *ScalarExprEmitter::EmitIncDecConsiderOverflowBehavior(
2511     const UnaryOperator *E, llvm::Value *InVal, bool IsInc) {
2512   llvm::Value *Amount =
2513       llvm::ConstantInt::get(InVal->getType(), IsInc ? 1 : -1, true);
2514   StringRef Name = IsInc ? "inc" : "dec";
2515   switch (CGF.getLangOpts().getSignedOverflowBehavior()) {
2516   case LangOptions::SOB_Defined:
2517     return Builder.CreateAdd(InVal, Amount, Name);
2518   case LangOptions::SOB_Undefined:
2519     if (!CGF.SanOpts.has(SanitizerKind::SignedIntegerOverflow))
2520       return Builder.CreateNSWAdd(InVal, Amount, Name);
2521     [[fallthrough]];
2522   case LangOptions::SOB_Trapping:
2523     if (!E->canOverflow())
2524       return Builder.CreateNSWAdd(InVal, Amount, Name);
2525     return EmitOverflowCheckedBinOp(createBinOpInfoFromIncDec(
2526         E, InVal, IsInc, E->getFPFeaturesInEffect(CGF.getLangOpts())));
2527   }
2528   llvm_unreachable("Unknown SignedOverflowBehaviorTy");
2529 }
2530 
2531 namespace {
2532 /// Handles check and update for lastprivate conditional variables.
2533 class OMPLastprivateConditionalUpdateRAII {
2534 private:
2535   CodeGenFunction &CGF;
2536   const UnaryOperator *E;
2537 
2538 public:
2539   OMPLastprivateConditionalUpdateRAII(CodeGenFunction &CGF,
2540                                       const UnaryOperator *E)
2541       : CGF(CGF), E(E) {}
2542   ~OMPLastprivateConditionalUpdateRAII() {
2543     if (CGF.getLangOpts().OpenMP)
2544       CGF.CGM.getOpenMPRuntime().checkAndEmitLastprivateConditional(
2545           CGF, E->getSubExpr());
2546   }
2547 };
2548 } // namespace
2549 
2550 llvm::Value *
2551 ScalarExprEmitter::EmitScalarPrePostIncDec(const UnaryOperator *E, LValue LV,
2552                                            bool isInc, bool isPre) {
2553   OMPLastprivateConditionalUpdateRAII OMPRegion(CGF, E);
2554   QualType type = E->getSubExpr()->getType();
2555   llvm::PHINode *atomicPHI = nullptr;
2556   llvm::Value *value;
2557   llvm::Value *input;
2558 
2559   int amount = (isInc ? 1 : -1);
2560   bool isSubtraction = !isInc;
2561 
2562   if (const AtomicType *atomicTy = type->getAs<AtomicType>()) {
2563     type = atomicTy->getValueType();
2564     if (isInc && type->isBooleanType()) {
2565       llvm::Value *True = CGF.EmitToMemory(Builder.getTrue(), type);
2566       if (isPre) {
2567         Builder.CreateStore(True, LV.getAddress(CGF), LV.isVolatileQualified())
2568             ->setAtomic(llvm::AtomicOrdering::SequentiallyConsistent);
2569         return Builder.getTrue();
2570       }
2571       // For atomic bool increment, we just store true and return it for
2572       // preincrement, do an atomic swap with true for postincrement
2573       return Builder.CreateAtomicRMW(
2574           llvm::AtomicRMWInst::Xchg, LV.getAddress(CGF), True,
2575           llvm::AtomicOrdering::SequentiallyConsistent);
2576     }
2577     // Special case for atomic increment / decrement on integers, emit
2578     // atomicrmw instructions.  We skip this if we want to be doing overflow
2579     // checking, and fall into the slow path with the atomic cmpxchg loop.
2580     if (!type->isBooleanType() && type->isIntegerType() &&
2581         !(type->isUnsignedIntegerType() &&
2582           CGF.SanOpts.has(SanitizerKind::UnsignedIntegerOverflow)) &&
2583         CGF.getLangOpts().getSignedOverflowBehavior() !=
2584             LangOptions::SOB_Trapping) {
2585       llvm::AtomicRMWInst::BinOp aop = isInc ? llvm::AtomicRMWInst::Add :
2586         llvm::AtomicRMWInst::Sub;
2587       llvm::Instruction::BinaryOps op = isInc ? llvm::Instruction::Add :
2588         llvm::Instruction::Sub;
2589       llvm::Value *amt = CGF.EmitToMemory(
2590           llvm::ConstantInt::get(ConvertType(type), 1, true), type);
2591       llvm::Value *old =
2592           Builder.CreateAtomicRMW(aop, LV.getAddress(CGF), amt,
2593                                   llvm::AtomicOrdering::SequentiallyConsistent);
2594       return isPre ? Builder.CreateBinOp(op, old, amt) : old;
2595     }
2596     value = EmitLoadOfLValue(LV, E->getExprLoc());
2597     input = value;
2598     // For every other atomic operation, we need to emit a load-op-cmpxchg loop
2599     llvm::BasicBlock *startBB = Builder.GetInsertBlock();
2600     llvm::BasicBlock *opBB = CGF.createBasicBlock("atomic_op", CGF.CurFn);
2601     value = CGF.EmitToMemory(value, type);
2602     Builder.CreateBr(opBB);
2603     Builder.SetInsertPoint(opBB);
2604     atomicPHI = Builder.CreatePHI(value->getType(), 2);
2605     atomicPHI->addIncoming(value, startBB);
2606     value = atomicPHI;
2607   } else {
2608     value = EmitLoadOfLValue(LV, E->getExprLoc());
2609     input = value;
2610   }
2611 
2612   // Special case of integer increment that we have to check first: bool++.
2613   // Due to promotion rules, we get:
2614   //   bool++ -> bool = bool + 1
2615   //          -> bool = (int)bool + 1
2616   //          -> bool = ((int)bool + 1 != 0)
2617   // An interesting aspect of this is that increment is always true.
2618   // Decrement does not have this property.
2619   if (isInc && type->isBooleanType()) {
2620     value = Builder.getTrue();
2621 
2622   // Most common case by far: integer increment.
2623   } else if (type->isIntegerType()) {
2624     QualType promotedType;
2625     bool canPerformLossyDemotionCheck = false;
2626     if (CGF.getContext().isPromotableIntegerType(type)) {
2627       promotedType = CGF.getContext().getPromotedIntegerType(type);
2628       assert(promotedType != type && "Shouldn't promote to the same type.");
2629       canPerformLossyDemotionCheck = true;
2630       canPerformLossyDemotionCheck &=
2631           CGF.getContext().getCanonicalType(type) !=
2632           CGF.getContext().getCanonicalType(promotedType);
2633       canPerformLossyDemotionCheck &=
2634           PromotionIsPotentiallyEligibleForImplicitIntegerConversionCheck(
2635               type, promotedType);
2636       assert((!canPerformLossyDemotionCheck ||
2637               type->isSignedIntegerOrEnumerationType() ||
2638               promotedType->isSignedIntegerOrEnumerationType() ||
2639               ConvertType(type)->getScalarSizeInBits() ==
2640                   ConvertType(promotedType)->getScalarSizeInBits()) &&
2641              "The following check expects that if we do promotion to different "
2642              "underlying canonical type, at least one of the types (either "
2643              "base or promoted) will be signed, or the bitwidths will match.");
2644     }
2645     if (CGF.SanOpts.hasOneOf(
2646             SanitizerKind::ImplicitIntegerArithmeticValueChange) &&
2647         canPerformLossyDemotionCheck) {
2648       // While `x += 1` (for `x` with width less than int) is modeled as
2649       // promotion+arithmetics+demotion, and we can catch lossy demotion with
2650       // ease; inc/dec with width less than int can't overflow because of
2651       // promotion rules, so we omit promotion+demotion, which means that we can
2652       // not catch lossy "demotion". Because we still want to catch these cases
2653       // when the sanitizer is enabled, we perform the promotion, then perform
2654       // the increment/decrement in the wider type, and finally
2655       // perform the demotion. This will catch lossy demotions.
2656 
2657       value = EmitScalarConversion(value, type, promotedType, E->getExprLoc());
2658       Value *amt = llvm::ConstantInt::get(value->getType(), amount, true);
2659       value = Builder.CreateAdd(value, amt, isInc ? "inc" : "dec");
2660       // Do pass non-default ScalarConversionOpts so that sanitizer check is
2661       // emitted.
2662       value = EmitScalarConversion(value, promotedType, type, E->getExprLoc(),
2663                                    ScalarConversionOpts(CGF.SanOpts));
2664 
2665       // Note that signed integer inc/dec with width less than int can't
2666       // overflow because of promotion rules; we're just eliding a few steps
2667       // here.
2668     } else if (E->canOverflow() && type->isSignedIntegerOrEnumerationType()) {
2669       value = EmitIncDecConsiderOverflowBehavior(E, value, isInc);
2670     } else if (E->canOverflow() && type->isUnsignedIntegerType() &&
2671                CGF.SanOpts.has(SanitizerKind::UnsignedIntegerOverflow)) {
2672       value = EmitOverflowCheckedBinOp(createBinOpInfoFromIncDec(
2673           E, value, isInc, E->getFPFeaturesInEffect(CGF.getLangOpts())));
2674     } else {
2675       llvm::Value *amt = llvm::ConstantInt::get(value->getType(), amount, true);
2676       value = Builder.CreateAdd(value, amt, isInc ? "inc" : "dec");
2677     }
2678 
2679   // Next most common: pointer increment.
2680   } else if (const PointerType *ptr = type->getAs<PointerType>()) {
2681     QualType type = ptr->getPointeeType();
2682 
2683     // VLA types don't have constant size.
2684     if (const VariableArrayType *vla
2685           = CGF.getContext().getAsVariableArrayType(type)) {
2686       llvm::Value *numElts = CGF.getVLASize(vla).NumElts;
2687       if (!isInc) numElts = Builder.CreateNSWNeg(numElts, "vla.negsize");
2688       llvm::Type *elemTy = CGF.ConvertTypeForMem(vla->getElementType());
2689       if (CGF.getLangOpts().isSignedOverflowDefined())
2690         value = Builder.CreateGEP(elemTy, value, numElts, "vla.inc");
2691       else
2692         value = CGF.EmitCheckedInBoundsGEP(
2693             elemTy, value, numElts, /*SignedIndices=*/false, isSubtraction,
2694             E->getExprLoc(), "vla.inc");
2695 
2696     // Arithmetic on function pointers (!) is just +-1.
2697     } else if (type->isFunctionType()) {
2698       llvm::Value *amt = Builder.getInt32(amount);
2699 
2700       if (CGF.getLangOpts().isSignedOverflowDefined())
2701         value = Builder.CreateGEP(CGF.Int8Ty, value, amt, "incdec.funcptr");
2702       else
2703         value =
2704             CGF.EmitCheckedInBoundsGEP(CGF.Int8Ty, value, amt,
2705                                        /*SignedIndices=*/false, isSubtraction,
2706                                        E->getExprLoc(), "incdec.funcptr");
2707 
2708     // For everything else, we can just do a simple increment.
2709     } else {
2710       llvm::Value *amt = Builder.getInt32(amount);
2711       llvm::Type *elemTy = CGF.ConvertTypeForMem(type);
2712       if (CGF.getLangOpts().isSignedOverflowDefined())
2713         value = Builder.CreateGEP(elemTy, value, amt, "incdec.ptr");
2714       else
2715         value = CGF.EmitCheckedInBoundsGEP(
2716             elemTy, value, amt, /*SignedIndices=*/false, isSubtraction,
2717             E->getExprLoc(), "incdec.ptr");
2718     }
2719 
2720   // Vector increment/decrement.
2721   } else if (type->isVectorType()) {
2722     if (type->hasIntegerRepresentation()) {
2723       llvm::Value *amt = llvm::ConstantInt::get(value->getType(), amount);
2724 
2725       value = Builder.CreateAdd(value, amt, isInc ? "inc" : "dec");
2726     } else {
2727       value = Builder.CreateFAdd(
2728                   value,
2729                   llvm::ConstantFP::get(value->getType(), amount),
2730                   isInc ? "inc" : "dec");
2731     }
2732 
2733   // Floating point.
2734   } else if (type->isRealFloatingType()) {
2735     // Add the inc/dec to the real part.
2736     llvm::Value *amt;
2737     CodeGenFunction::CGFPOptionsRAII FPOptsRAII(CGF, E);
2738 
2739     if (type->isHalfType() && !CGF.getContext().getLangOpts().NativeHalfType) {
2740       // Another special case: half FP increment should be done via float
2741       if (CGF.getContext().getTargetInfo().useFP16ConversionIntrinsics()) {
2742         value = Builder.CreateCall(
2743             CGF.CGM.getIntrinsic(llvm::Intrinsic::convert_from_fp16,
2744                                  CGF.CGM.FloatTy),
2745             input, "incdec.conv");
2746       } else {
2747         value = Builder.CreateFPExt(input, CGF.CGM.FloatTy, "incdec.conv");
2748       }
2749     }
2750 
2751     if (value->getType()->isFloatTy())
2752       amt = llvm::ConstantFP::get(VMContext,
2753                                   llvm::APFloat(static_cast<float>(amount)));
2754     else if (value->getType()->isDoubleTy())
2755       amt = llvm::ConstantFP::get(VMContext,
2756                                   llvm::APFloat(static_cast<double>(amount)));
2757     else {
2758       // Remaining types are Half, Bfloat16, LongDouble, __ibm128 or __float128.
2759       // Convert from float.
2760       llvm::APFloat F(static_cast<float>(amount));
2761       bool ignored;
2762       const llvm::fltSemantics *FS;
2763       // Don't use getFloatTypeSemantics because Half isn't
2764       // necessarily represented using the "half" LLVM type.
2765       if (value->getType()->isFP128Ty())
2766         FS = &CGF.getTarget().getFloat128Format();
2767       else if (value->getType()->isHalfTy())
2768         FS = &CGF.getTarget().getHalfFormat();
2769       else if (value->getType()->isBFloatTy())
2770         FS = &CGF.getTarget().getBFloat16Format();
2771       else if (value->getType()->isPPC_FP128Ty())
2772         FS = &CGF.getTarget().getIbm128Format();
2773       else
2774         FS = &CGF.getTarget().getLongDoubleFormat();
2775       F.convert(*FS, llvm::APFloat::rmTowardZero, &ignored);
2776       amt = llvm::ConstantFP::get(VMContext, F);
2777     }
2778     value = Builder.CreateFAdd(value, amt, isInc ? "inc" : "dec");
2779 
2780     if (type->isHalfType() && !CGF.getContext().getLangOpts().NativeHalfType) {
2781       if (CGF.getContext().getTargetInfo().useFP16ConversionIntrinsics()) {
2782         value = Builder.CreateCall(
2783             CGF.CGM.getIntrinsic(llvm::Intrinsic::convert_to_fp16,
2784                                  CGF.CGM.FloatTy),
2785             value, "incdec.conv");
2786       } else {
2787         value = Builder.CreateFPTrunc(value, input->getType(), "incdec.conv");
2788       }
2789     }
2790 
2791   // Fixed-point types.
2792   } else if (type->isFixedPointType()) {
2793     // Fixed-point types are tricky. In some cases, it isn't possible to
2794     // represent a 1 or a -1 in the type at all. Piggyback off of
2795     // EmitFixedPointBinOp to avoid having to reimplement saturation.
2796     BinOpInfo Info;
2797     Info.E = E;
2798     Info.Ty = E->getType();
2799     Info.Opcode = isInc ? BO_Add : BO_Sub;
2800     Info.LHS = value;
2801     Info.RHS = llvm::ConstantInt::get(value->getType(), 1, false);
2802     // If the type is signed, it's better to represent this as +(-1) or -(-1),
2803     // since -1 is guaranteed to be representable.
2804     if (type->isSignedFixedPointType()) {
2805       Info.Opcode = isInc ? BO_Sub : BO_Add;
2806       Info.RHS = Builder.CreateNeg(Info.RHS);
2807     }
2808     // Now, convert from our invented integer literal to the type of the unary
2809     // op. This will upscale and saturate if necessary. This value can become
2810     // undef in some cases.
2811     llvm::FixedPointBuilder<CGBuilderTy> FPBuilder(Builder);
2812     auto DstSema = CGF.getContext().getFixedPointSemantics(Info.Ty);
2813     Info.RHS = FPBuilder.CreateIntegerToFixed(Info.RHS, true, DstSema);
2814     value = EmitFixedPointBinOp(Info);
2815 
2816   // Objective-C pointer types.
2817   } else {
2818     const ObjCObjectPointerType *OPT = type->castAs<ObjCObjectPointerType>();
2819 
2820     CharUnits size = CGF.getContext().getTypeSizeInChars(OPT->getObjectType());
2821     if (!isInc) size = -size;
2822     llvm::Value *sizeValue =
2823       llvm::ConstantInt::get(CGF.SizeTy, size.getQuantity());
2824 
2825     if (CGF.getLangOpts().isSignedOverflowDefined())
2826       value = Builder.CreateGEP(CGF.Int8Ty, value, sizeValue, "incdec.objptr");
2827     else
2828       value = CGF.EmitCheckedInBoundsGEP(
2829           CGF.Int8Ty, value, sizeValue, /*SignedIndices=*/false, isSubtraction,
2830           E->getExprLoc(), "incdec.objptr");
2831     value = Builder.CreateBitCast(value, input->getType());
2832   }
2833 
2834   if (atomicPHI) {
2835     llvm::BasicBlock *curBlock = Builder.GetInsertBlock();
2836     llvm::BasicBlock *contBB = CGF.createBasicBlock("atomic_cont", CGF.CurFn);
2837     auto Pair = CGF.EmitAtomicCompareExchange(
2838         LV, RValue::get(atomicPHI), RValue::get(value), E->getExprLoc());
2839     llvm::Value *old = CGF.EmitToMemory(Pair.first.getScalarVal(), type);
2840     llvm::Value *success = Pair.second;
2841     atomicPHI->addIncoming(old, curBlock);
2842     Builder.CreateCondBr(success, contBB, atomicPHI->getParent());
2843     Builder.SetInsertPoint(contBB);
2844     return isPre ? value : input;
2845   }
2846 
2847   // Store the updated result through the lvalue.
2848   if (LV.isBitField())
2849     CGF.EmitStoreThroughBitfieldLValue(RValue::get(value), LV, &value);
2850   else
2851     CGF.EmitStoreThroughLValue(RValue::get(value), LV);
2852 
2853   // If this is a postinc, return the value read from memory, otherwise use the
2854   // updated value.
2855   return isPre ? value : input;
2856 }
2857 
2858 
2859 Value *ScalarExprEmitter::VisitUnaryPlus(const UnaryOperator *E,
2860                                          QualType PromotionType) {
2861   QualType promotionTy = PromotionType.isNull()
2862                              ? getPromotionType(E->getSubExpr()->getType())
2863                              : PromotionType;
2864   Value *result = VisitPlus(E, promotionTy);
2865   if (result && !promotionTy.isNull())
2866     result = EmitUnPromotedValue(result, E->getType());
2867   return result;
2868 }
2869 
2870 Value *ScalarExprEmitter::VisitPlus(const UnaryOperator *E,
2871                                     QualType PromotionType) {
2872   // This differs from gcc, though, most likely due to a bug in gcc.
2873   TestAndClearIgnoreResultAssign();
2874   if (!PromotionType.isNull())
2875     return CGF.EmitPromotedScalarExpr(E->getSubExpr(), PromotionType);
2876   return Visit(E->getSubExpr());
2877 }
2878 
2879 Value *ScalarExprEmitter::VisitUnaryMinus(const UnaryOperator *E,
2880                                           QualType PromotionType) {
2881   QualType promotionTy = PromotionType.isNull()
2882                              ? getPromotionType(E->getSubExpr()->getType())
2883                              : PromotionType;
2884   Value *result = VisitMinus(E, promotionTy);
2885   if (result && !promotionTy.isNull())
2886     result = EmitUnPromotedValue(result, E->getType());
2887   return result;
2888 }
2889 
2890 Value *ScalarExprEmitter::VisitMinus(const UnaryOperator *E,
2891                                      QualType PromotionType) {
2892   TestAndClearIgnoreResultAssign();
2893   Value *Op;
2894   if (!PromotionType.isNull())
2895     Op = CGF.EmitPromotedScalarExpr(E->getSubExpr(), PromotionType);
2896   else
2897     Op = Visit(E->getSubExpr());
2898 
2899   // Generate a unary FNeg for FP ops.
2900   if (Op->getType()->isFPOrFPVectorTy())
2901     return Builder.CreateFNeg(Op, "fneg");
2902 
2903   // Emit unary minus with EmitSub so we handle overflow cases etc.
2904   BinOpInfo BinOp;
2905   BinOp.RHS = Op;
2906   BinOp.LHS = llvm::Constant::getNullValue(BinOp.RHS->getType());
2907   BinOp.Ty = E->getType();
2908   BinOp.Opcode = BO_Sub;
2909   BinOp.FPFeatures = E->getFPFeaturesInEffect(CGF.getLangOpts());
2910   BinOp.E = E;
2911   return EmitSub(BinOp);
2912 }
2913 
2914 Value *ScalarExprEmitter::VisitUnaryNot(const UnaryOperator *E) {
2915   TestAndClearIgnoreResultAssign();
2916   Value *Op = Visit(E->getSubExpr());
2917   return Builder.CreateNot(Op, "not");
2918 }
2919 
2920 Value *ScalarExprEmitter::VisitUnaryLNot(const UnaryOperator *E) {
2921   // Perform vector logical not on comparison with zero vector.
2922   if (E->getType()->isVectorType() &&
2923       E->getType()->castAs<VectorType>()->getVectorKind() ==
2924           VectorKind::Generic) {
2925     Value *Oper = Visit(E->getSubExpr());
2926     Value *Zero = llvm::Constant::getNullValue(Oper->getType());
2927     Value *Result;
2928     if (Oper->getType()->isFPOrFPVectorTy()) {
2929       CodeGenFunction::CGFPOptionsRAII FPOptsRAII(
2930           CGF, E->getFPFeaturesInEffect(CGF.getLangOpts()));
2931       Result = Builder.CreateFCmp(llvm::CmpInst::FCMP_OEQ, Oper, Zero, "cmp");
2932     } else
2933       Result = Builder.CreateICmp(llvm::CmpInst::ICMP_EQ, Oper, Zero, "cmp");
2934     return Builder.CreateSExt(Result, ConvertType(E->getType()), "sext");
2935   }
2936 
2937   // Compare operand to zero.
2938   Value *BoolVal = CGF.EvaluateExprAsBool(E->getSubExpr());
2939 
2940   // Invert value.
2941   // TODO: Could dynamically modify easy computations here.  For example, if
2942   // the operand is an icmp ne, turn into icmp eq.
2943   BoolVal = Builder.CreateNot(BoolVal, "lnot");
2944 
2945   // ZExt result to the expr type.
2946   return Builder.CreateZExt(BoolVal, ConvertType(E->getType()), "lnot.ext");
2947 }
2948 
2949 Value *ScalarExprEmitter::VisitOffsetOfExpr(OffsetOfExpr *E) {
2950   // Try folding the offsetof to a constant.
2951   Expr::EvalResult EVResult;
2952   if (E->EvaluateAsInt(EVResult, CGF.getContext())) {
2953     llvm::APSInt Value = EVResult.Val.getInt();
2954     return Builder.getInt(Value);
2955   }
2956 
2957   // Loop over the components of the offsetof to compute the value.
2958   unsigned n = E->getNumComponents();
2959   llvm::Type* ResultType = ConvertType(E->getType());
2960   llvm::Value* Result = llvm::Constant::getNullValue(ResultType);
2961   QualType CurrentType = E->getTypeSourceInfo()->getType();
2962   for (unsigned i = 0; i != n; ++i) {
2963     OffsetOfNode ON = E->getComponent(i);
2964     llvm::Value *Offset = nullptr;
2965     switch (ON.getKind()) {
2966     case OffsetOfNode::Array: {
2967       // Compute the index
2968       Expr *IdxExpr = E->getIndexExpr(ON.getArrayExprIndex());
2969       llvm::Value* Idx = CGF.EmitScalarExpr(IdxExpr);
2970       bool IdxSigned = IdxExpr->getType()->isSignedIntegerOrEnumerationType();
2971       Idx = Builder.CreateIntCast(Idx, ResultType, IdxSigned, "conv");
2972 
2973       // Save the element type
2974       CurrentType =
2975           CGF.getContext().getAsArrayType(CurrentType)->getElementType();
2976 
2977       // Compute the element size
2978       llvm::Value* ElemSize = llvm::ConstantInt::get(ResultType,
2979           CGF.getContext().getTypeSizeInChars(CurrentType).getQuantity());
2980 
2981       // Multiply out to compute the result
2982       Offset = Builder.CreateMul(Idx, ElemSize);
2983       break;
2984     }
2985 
2986     case OffsetOfNode::Field: {
2987       FieldDecl *MemberDecl = ON.getField();
2988       RecordDecl *RD = CurrentType->castAs<RecordType>()->getDecl();
2989       const ASTRecordLayout &RL = CGF.getContext().getASTRecordLayout(RD);
2990 
2991       // Compute the index of the field in its parent.
2992       unsigned i = 0;
2993       // FIXME: It would be nice if we didn't have to loop here!
2994       for (RecordDecl::field_iterator Field = RD->field_begin(),
2995                                       FieldEnd = RD->field_end();
2996            Field != FieldEnd; ++Field, ++i) {
2997         if (*Field == MemberDecl)
2998           break;
2999       }
3000       assert(i < RL.getFieldCount() && "offsetof field in wrong type");
3001 
3002       // Compute the offset to the field
3003       int64_t OffsetInt = RL.getFieldOffset(i) /
3004                           CGF.getContext().getCharWidth();
3005       Offset = llvm::ConstantInt::get(ResultType, OffsetInt);
3006 
3007       // Save the element type.
3008       CurrentType = MemberDecl->getType();
3009       break;
3010     }
3011 
3012     case OffsetOfNode::Identifier:
3013       llvm_unreachable("dependent __builtin_offsetof");
3014 
3015     case OffsetOfNode::Base: {
3016       if (ON.getBase()->isVirtual()) {
3017         CGF.ErrorUnsupported(E, "virtual base in offsetof");
3018         continue;
3019       }
3020 
3021       RecordDecl *RD = CurrentType->castAs<RecordType>()->getDecl();
3022       const ASTRecordLayout &RL = CGF.getContext().getASTRecordLayout(RD);
3023 
3024       // Save the element type.
3025       CurrentType = ON.getBase()->getType();
3026 
3027       // Compute the offset to the base.
3028       auto *BaseRT = CurrentType->castAs<RecordType>();
3029       auto *BaseRD = cast<CXXRecordDecl>(BaseRT->getDecl());
3030       CharUnits OffsetInt = RL.getBaseClassOffset(BaseRD);
3031       Offset = llvm::ConstantInt::get(ResultType, OffsetInt.getQuantity());
3032       break;
3033     }
3034     }
3035     Result = Builder.CreateAdd(Result, Offset);
3036   }
3037   return Result;
3038 }
3039 
3040 /// VisitUnaryExprOrTypeTraitExpr - Return the size or alignment of the type of
3041 /// argument of the sizeof expression as an integer.
3042 Value *
3043 ScalarExprEmitter::VisitUnaryExprOrTypeTraitExpr(
3044                               const UnaryExprOrTypeTraitExpr *E) {
3045   QualType TypeToSize = E->getTypeOfArgument();
3046   if (auto Kind = E->getKind();
3047       Kind == UETT_SizeOf || Kind == UETT_DataSizeOf) {
3048     if (const VariableArrayType *VAT =
3049             CGF.getContext().getAsVariableArrayType(TypeToSize)) {
3050       if (E->isArgumentType()) {
3051         // sizeof(type) - make sure to emit the VLA size.
3052         CGF.EmitVariablyModifiedType(TypeToSize);
3053       } else {
3054         // C99 6.5.3.4p2: If the argument is an expression of type
3055         // VLA, it is evaluated.
3056         CGF.EmitIgnoredExpr(E->getArgumentExpr());
3057       }
3058 
3059       auto VlaSize = CGF.getVLASize(VAT);
3060       llvm::Value *size = VlaSize.NumElts;
3061 
3062       // Scale the number of non-VLA elements by the non-VLA element size.
3063       CharUnits eltSize = CGF.getContext().getTypeSizeInChars(VlaSize.Type);
3064       if (!eltSize.isOne())
3065         size = CGF.Builder.CreateNUWMul(CGF.CGM.getSize(eltSize), size);
3066 
3067       return size;
3068     }
3069   } else if (E->getKind() == UETT_OpenMPRequiredSimdAlign) {
3070     auto Alignment =
3071         CGF.getContext()
3072             .toCharUnitsFromBits(CGF.getContext().getOpenMPDefaultSimdAlign(
3073                 E->getTypeOfArgument()->getPointeeType()))
3074             .getQuantity();
3075     return llvm::ConstantInt::get(CGF.SizeTy, Alignment);
3076   } else if (E->getKind() == UETT_VectorElements) {
3077     auto *VecTy = cast<llvm::VectorType>(ConvertType(E->getTypeOfArgument()));
3078     return Builder.CreateElementCount(CGF.SizeTy, VecTy->getElementCount());
3079   }
3080 
3081   // If this isn't sizeof(vla), the result must be constant; use the constant
3082   // folding logic so we don't have to duplicate it here.
3083   return Builder.getInt(E->EvaluateKnownConstInt(CGF.getContext()));
3084 }
3085 
3086 Value *ScalarExprEmitter::VisitUnaryReal(const UnaryOperator *E,
3087                                          QualType PromotionType) {
3088   QualType promotionTy = PromotionType.isNull()
3089                              ? getPromotionType(E->getSubExpr()->getType())
3090                              : PromotionType;
3091   Value *result = VisitReal(E, promotionTy);
3092   if (result && !promotionTy.isNull())
3093     result = EmitUnPromotedValue(result, E->getType());
3094   return result;
3095 }
3096 
3097 Value *ScalarExprEmitter::VisitReal(const UnaryOperator *E,
3098                                     QualType PromotionType) {
3099   Expr *Op = E->getSubExpr();
3100   if (Op->getType()->isAnyComplexType()) {
3101     // If it's an l-value, load through the appropriate subobject l-value.
3102     // Note that we have to ask E because Op might be an l-value that
3103     // this won't work for, e.g. an Obj-C property.
3104     if (E->isGLValue())  {
3105       if (!PromotionType.isNull()) {
3106         CodeGenFunction::ComplexPairTy result = CGF.EmitComplexExpr(
3107             Op, /*IgnoreReal*/ IgnoreResultAssign, /*IgnoreImag*/ true);
3108         if (result.first)
3109           result.first = CGF.EmitPromotedValue(result, PromotionType).first;
3110         return result.first;
3111       } else {
3112         return CGF.EmitLoadOfLValue(CGF.EmitLValue(E), E->getExprLoc())
3113             .getScalarVal();
3114       }
3115     }
3116     // Otherwise, calculate and project.
3117     return CGF.EmitComplexExpr(Op, false, true).first;
3118   }
3119 
3120   if (!PromotionType.isNull())
3121     return CGF.EmitPromotedScalarExpr(Op, PromotionType);
3122   return Visit(Op);
3123 }
3124 
3125 Value *ScalarExprEmitter::VisitUnaryImag(const UnaryOperator *E,
3126                                          QualType PromotionType) {
3127   QualType promotionTy = PromotionType.isNull()
3128                              ? getPromotionType(E->getSubExpr()->getType())
3129                              : PromotionType;
3130   Value *result = VisitImag(E, promotionTy);
3131   if (result && !promotionTy.isNull())
3132     result = EmitUnPromotedValue(result, E->getType());
3133   return result;
3134 }
3135 
3136 Value *ScalarExprEmitter::VisitImag(const UnaryOperator *E,
3137                                     QualType PromotionType) {
3138   Expr *Op = E->getSubExpr();
3139   if (Op->getType()->isAnyComplexType()) {
3140     // If it's an l-value, load through the appropriate subobject l-value.
3141     // Note that we have to ask E because Op might be an l-value that
3142     // this won't work for, e.g. an Obj-C property.
3143     if (Op->isGLValue()) {
3144       if (!PromotionType.isNull()) {
3145         CodeGenFunction::ComplexPairTy result = CGF.EmitComplexExpr(
3146             Op, /*IgnoreReal*/ true, /*IgnoreImag*/ IgnoreResultAssign);
3147         if (result.second)
3148           result.second = CGF.EmitPromotedValue(result, PromotionType).second;
3149         return result.second;
3150       } else {
3151         return CGF.EmitLoadOfLValue(CGF.EmitLValue(E), E->getExprLoc())
3152             .getScalarVal();
3153       }
3154     }
3155     // Otherwise, calculate and project.
3156     return CGF.EmitComplexExpr(Op, true, false).second;
3157   }
3158 
3159   // __imag on a scalar returns zero.  Emit the subexpr to ensure side
3160   // effects are evaluated, but not the actual value.
3161   if (Op->isGLValue())
3162     CGF.EmitLValue(Op);
3163   else if (!PromotionType.isNull())
3164     CGF.EmitPromotedScalarExpr(Op, PromotionType);
3165   else
3166     CGF.EmitScalarExpr(Op, true);
3167   if (!PromotionType.isNull())
3168     return llvm::Constant::getNullValue(ConvertType(PromotionType));
3169   return llvm::Constant::getNullValue(ConvertType(E->getType()));
3170 }
3171 
3172 //===----------------------------------------------------------------------===//
3173 //                           Binary Operators
3174 //===----------------------------------------------------------------------===//
3175 
3176 Value *ScalarExprEmitter::EmitPromotedValue(Value *result,
3177                                             QualType PromotionType) {
3178   return CGF.Builder.CreateFPExt(result, ConvertType(PromotionType), "ext");
3179 }
3180 
3181 Value *ScalarExprEmitter::EmitUnPromotedValue(Value *result,
3182                                               QualType ExprType) {
3183   return CGF.Builder.CreateFPTrunc(result, ConvertType(ExprType), "unpromotion");
3184 }
3185 
3186 Value *ScalarExprEmitter::EmitPromoted(const Expr *E, QualType PromotionType) {
3187   E = E->IgnoreParens();
3188   if (auto BO = dyn_cast<BinaryOperator>(E)) {
3189     switch (BO->getOpcode()) {
3190 #define HANDLE_BINOP(OP)                                                       \
3191   case BO_##OP:                                                                \
3192     return Emit##OP(EmitBinOps(BO, PromotionType));
3193       HANDLE_BINOP(Add)
3194       HANDLE_BINOP(Sub)
3195       HANDLE_BINOP(Mul)
3196       HANDLE_BINOP(Div)
3197 #undef HANDLE_BINOP
3198     default:
3199       break;
3200     }
3201   } else if (auto UO = dyn_cast<UnaryOperator>(E)) {
3202     switch (UO->getOpcode()) {
3203     case UO_Imag:
3204       return VisitImag(UO, PromotionType);
3205     case UO_Real:
3206       return VisitReal(UO, PromotionType);
3207     case UO_Minus:
3208       return VisitMinus(UO, PromotionType);
3209     case UO_Plus:
3210       return VisitPlus(UO, PromotionType);
3211     default:
3212       break;
3213     }
3214   }
3215   auto result = Visit(const_cast<Expr *>(E));
3216   if (result) {
3217     if (!PromotionType.isNull())
3218       return EmitPromotedValue(result, PromotionType);
3219     else
3220       return EmitUnPromotedValue(result, E->getType());
3221   }
3222   return result;
3223 }
3224 
3225 BinOpInfo ScalarExprEmitter::EmitBinOps(const BinaryOperator *E,
3226                                         QualType PromotionType) {
3227   TestAndClearIgnoreResultAssign();
3228   BinOpInfo Result;
3229   Result.LHS = CGF.EmitPromotedScalarExpr(E->getLHS(), PromotionType);
3230   Result.RHS = CGF.EmitPromotedScalarExpr(E->getRHS(), PromotionType);
3231   if (!PromotionType.isNull())
3232     Result.Ty = PromotionType;
3233   else
3234     Result.Ty  = E->getType();
3235   Result.Opcode = E->getOpcode();
3236   Result.FPFeatures = E->getFPFeaturesInEffect(CGF.getLangOpts());
3237   Result.E = E;
3238   return Result;
3239 }
3240 
3241 LValue ScalarExprEmitter::EmitCompoundAssignLValue(
3242                                               const CompoundAssignOperator *E,
3243                         Value *(ScalarExprEmitter::*Func)(const BinOpInfo &),
3244                                                    Value *&Result) {
3245   QualType LHSTy = E->getLHS()->getType();
3246   BinOpInfo OpInfo;
3247 
3248   if (E->getComputationResultType()->isAnyComplexType())
3249     return CGF.EmitScalarCompoundAssignWithComplex(E, Result);
3250 
3251   // Emit the RHS first.  __block variables need to have the rhs evaluated
3252   // first, plus this should improve codegen a little.
3253 
3254   QualType PromotionTypeCR;
3255   PromotionTypeCR = getPromotionType(E->getComputationResultType());
3256   if (PromotionTypeCR.isNull())
3257       PromotionTypeCR = E->getComputationResultType();
3258   QualType PromotionTypeLHS = getPromotionType(E->getComputationLHSType());
3259   QualType PromotionTypeRHS = getPromotionType(E->getRHS()->getType());
3260   if (!PromotionTypeRHS.isNull())
3261     OpInfo.RHS = CGF.EmitPromotedScalarExpr(E->getRHS(), PromotionTypeRHS);
3262   else
3263     OpInfo.RHS = Visit(E->getRHS());
3264   OpInfo.Ty = PromotionTypeCR;
3265   OpInfo.Opcode = E->getOpcode();
3266   OpInfo.FPFeatures = E->getFPFeaturesInEffect(CGF.getLangOpts());
3267   OpInfo.E = E;
3268   // Load/convert the LHS.
3269   LValue LHSLV = EmitCheckedLValue(E->getLHS(), CodeGenFunction::TCK_Store);
3270 
3271   llvm::PHINode *atomicPHI = nullptr;
3272   if (const AtomicType *atomicTy = LHSTy->getAs<AtomicType>()) {
3273     QualType type = atomicTy->getValueType();
3274     if (!type->isBooleanType() && type->isIntegerType() &&
3275         !(type->isUnsignedIntegerType() &&
3276           CGF.SanOpts.has(SanitizerKind::UnsignedIntegerOverflow)) &&
3277         CGF.getLangOpts().getSignedOverflowBehavior() !=
3278             LangOptions::SOB_Trapping) {
3279       llvm::AtomicRMWInst::BinOp AtomicOp = llvm::AtomicRMWInst::BAD_BINOP;
3280       llvm::Instruction::BinaryOps Op;
3281       switch (OpInfo.Opcode) {
3282         // We don't have atomicrmw operands for *, %, /, <<, >>
3283         case BO_MulAssign: case BO_DivAssign:
3284         case BO_RemAssign:
3285         case BO_ShlAssign:
3286         case BO_ShrAssign:
3287           break;
3288         case BO_AddAssign:
3289           AtomicOp = llvm::AtomicRMWInst::Add;
3290           Op = llvm::Instruction::Add;
3291           break;
3292         case BO_SubAssign:
3293           AtomicOp = llvm::AtomicRMWInst::Sub;
3294           Op = llvm::Instruction::Sub;
3295           break;
3296         case BO_AndAssign:
3297           AtomicOp = llvm::AtomicRMWInst::And;
3298           Op = llvm::Instruction::And;
3299           break;
3300         case BO_XorAssign:
3301           AtomicOp = llvm::AtomicRMWInst::Xor;
3302           Op = llvm::Instruction::Xor;
3303           break;
3304         case BO_OrAssign:
3305           AtomicOp = llvm::AtomicRMWInst::Or;
3306           Op = llvm::Instruction::Or;
3307           break;
3308         default:
3309           llvm_unreachable("Invalid compound assignment type");
3310       }
3311       if (AtomicOp != llvm::AtomicRMWInst::BAD_BINOP) {
3312         llvm::Value *Amt = CGF.EmitToMemory(
3313             EmitScalarConversion(OpInfo.RHS, E->getRHS()->getType(), LHSTy,
3314                                  E->getExprLoc()),
3315             LHSTy);
3316         Value *OldVal = Builder.CreateAtomicRMW(
3317             AtomicOp, LHSLV.getAddress(CGF), Amt,
3318             llvm::AtomicOrdering::SequentiallyConsistent);
3319 
3320         // Since operation is atomic, the result type is guaranteed to be the
3321         // same as the input in LLVM terms.
3322         Result = Builder.CreateBinOp(Op, OldVal, Amt);
3323         return LHSLV;
3324       }
3325     }
3326     // FIXME: For floating point types, we should be saving and restoring the
3327     // floating point environment in the loop.
3328     llvm::BasicBlock *startBB = Builder.GetInsertBlock();
3329     llvm::BasicBlock *opBB = CGF.createBasicBlock("atomic_op", CGF.CurFn);
3330     OpInfo.LHS = EmitLoadOfLValue(LHSLV, E->getExprLoc());
3331     OpInfo.LHS = CGF.EmitToMemory(OpInfo.LHS, type);
3332     Builder.CreateBr(opBB);
3333     Builder.SetInsertPoint(opBB);
3334     atomicPHI = Builder.CreatePHI(OpInfo.LHS->getType(), 2);
3335     atomicPHI->addIncoming(OpInfo.LHS, startBB);
3336     OpInfo.LHS = atomicPHI;
3337   }
3338   else
3339     OpInfo.LHS = EmitLoadOfLValue(LHSLV, E->getExprLoc());
3340 
3341   CodeGenFunction::CGFPOptionsRAII FPOptsRAII(CGF, OpInfo.FPFeatures);
3342   SourceLocation Loc = E->getExprLoc();
3343   if (!PromotionTypeLHS.isNull())
3344     OpInfo.LHS = EmitScalarConversion(OpInfo.LHS, LHSTy, PromotionTypeLHS,
3345                                       E->getExprLoc());
3346   else
3347     OpInfo.LHS = EmitScalarConversion(OpInfo.LHS, LHSTy,
3348                                       E->getComputationLHSType(), Loc);
3349 
3350   // Expand the binary operator.
3351   Result = (this->*Func)(OpInfo);
3352 
3353   // Convert the result back to the LHS type,
3354   // potentially with Implicit Conversion sanitizer check.
3355   Result = EmitScalarConversion(Result, PromotionTypeCR, LHSTy, Loc,
3356                                 ScalarConversionOpts(CGF.SanOpts));
3357 
3358   if (atomicPHI) {
3359     llvm::BasicBlock *curBlock = Builder.GetInsertBlock();
3360     llvm::BasicBlock *contBB = CGF.createBasicBlock("atomic_cont", CGF.CurFn);
3361     auto Pair = CGF.EmitAtomicCompareExchange(
3362         LHSLV, RValue::get(atomicPHI), RValue::get(Result), E->getExprLoc());
3363     llvm::Value *old = CGF.EmitToMemory(Pair.first.getScalarVal(), LHSTy);
3364     llvm::Value *success = Pair.second;
3365     atomicPHI->addIncoming(old, curBlock);
3366     Builder.CreateCondBr(success, contBB, atomicPHI->getParent());
3367     Builder.SetInsertPoint(contBB);
3368     return LHSLV;
3369   }
3370 
3371   // Store the result value into the LHS lvalue. Bit-fields are handled
3372   // specially because the result is altered by the store, i.e., [C99 6.5.16p1]
3373   // 'An assignment expression has the value of the left operand after the
3374   // assignment...'.
3375   if (LHSLV.isBitField())
3376     CGF.EmitStoreThroughBitfieldLValue(RValue::get(Result), LHSLV, &Result);
3377   else
3378     CGF.EmitStoreThroughLValue(RValue::get(Result), LHSLV);
3379 
3380   if (CGF.getLangOpts().OpenMP)
3381     CGF.CGM.getOpenMPRuntime().checkAndEmitLastprivateConditional(CGF,
3382                                                                   E->getLHS());
3383   return LHSLV;
3384 }
3385 
3386 Value *ScalarExprEmitter::EmitCompoundAssign(const CompoundAssignOperator *E,
3387                       Value *(ScalarExprEmitter::*Func)(const BinOpInfo &)) {
3388   bool Ignore = TestAndClearIgnoreResultAssign();
3389   Value *RHS = nullptr;
3390   LValue LHS = EmitCompoundAssignLValue(E, Func, RHS);
3391 
3392   // If the result is clearly ignored, return now.
3393   if (Ignore)
3394     return nullptr;
3395 
3396   // The result of an assignment in C is the assigned r-value.
3397   if (!CGF.getLangOpts().CPlusPlus)
3398     return RHS;
3399 
3400   // If the lvalue is non-volatile, return the computed value of the assignment.
3401   if (!LHS.isVolatileQualified())
3402     return RHS;
3403 
3404   // Otherwise, reload the value.
3405   return EmitLoadOfLValue(LHS, E->getExprLoc());
3406 }
3407 
3408 void ScalarExprEmitter::EmitUndefinedBehaviorIntegerDivAndRemCheck(
3409     const BinOpInfo &Ops, llvm::Value *Zero, bool isDiv) {
3410   SmallVector<std::pair<llvm::Value *, SanitizerMask>, 2> Checks;
3411 
3412   if (CGF.SanOpts.has(SanitizerKind::IntegerDivideByZero)) {
3413     Checks.push_back(std::make_pair(Builder.CreateICmpNE(Ops.RHS, Zero),
3414                                     SanitizerKind::IntegerDivideByZero));
3415   }
3416 
3417   const auto *BO = cast<BinaryOperator>(Ops.E);
3418   if (CGF.SanOpts.has(SanitizerKind::SignedIntegerOverflow) &&
3419       Ops.Ty->hasSignedIntegerRepresentation() &&
3420       !IsWidenedIntegerOp(CGF.getContext(), BO->getLHS()) &&
3421       Ops.mayHaveIntegerOverflow()) {
3422     llvm::IntegerType *Ty = cast<llvm::IntegerType>(Zero->getType());
3423 
3424     llvm::Value *IntMin =
3425       Builder.getInt(llvm::APInt::getSignedMinValue(Ty->getBitWidth()));
3426     llvm::Value *NegOne = llvm::Constant::getAllOnesValue(Ty);
3427 
3428     llvm::Value *LHSCmp = Builder.CreateICmpNE(Ops.LHS, IntMin);
3429     llvm::Value *RHSCmp = Builder.CreateICmpNE(Ops.RHS, NegOne);
3430     llvm::Value *NotOverflow = Builder.CreateOr(LHSCmp, RHSCmp, "or");
3431     Checks.push_back(
3432         std::make_pair(NotOverflow, SanitizerKind::SignedIntegerOverflow));
3433   }
3434 
3435   if (Checks.size() > 0)
3436     EmitBinOpCheck(Checks, Ops);
3437 }
3438 
3439 Value *ScalarExprEmitter::EmitDiv(const BinOpInfo &Ops) {
3440   {
3441     CodeGenFunction::SanitizerScope SanScope(&CGF);
3442     if ((CGF.SanOpts.has(SanitizerKind::IntegerDivideByZero) ||
3443          CGF.SanOpts.has(SanitizerKind::SignedIntegerOverflow)) &&
3444         Ops.Ty->isIntegerType() &&
3445         (Ops.mayHaveIntegerDivisionByZero() || Ops.mayHaveIntegerOverflow())) {
3446       llvm::Value *Zero = llvm::Constant::getNullValue(ConvertType(Ops.Ty));
3447       EmitUndefinedBehaviorIntegerDivAndRemCheck(Ops, Zero, true);
3448     } else if (CGF.SanOpts.has(SanitizerKind::FloatDivideByZero) &&
3449                Ops.Ty->isRealFloatingType() &&
3450                Ops.mayHaveFloatDivisionByZero()) {
3451       llvm::Value *Zero = llvm::Constant::getNullValue(ConvertType(Ops.Ty));
3452       llvm::Value *NonZero = Builder.CreateFCmpUNE(Ops.RHS, Zero);
3453       EmitBinOpCheck(std::make_pair(NonZero, SanitizerKind::FloatDivideByZero),
3454                      Ops);
3455     }
3456   }
3457 
3458   if (Ops.Ty->isConstantMatrixType()) {
3459     llvm::MatrixBuilder MB(Builder);
3460     // We need to check the types of the operands of the operator to get the
3461     // correct matrix dimensions.
3462     auto *BO = cast<BinaryOperator>(Ops.E);
3463     (void)BO;
3464     assert(
3465         isa<ConstantMatrixType>(BO->getLHS()->getType().getCanonicalType()) &&
3466         "first operand must be a matrix");
3467     assert(BO->getRHS()->getType().getCanonicalType()->isArithmeticType() &&
3468            "second operand must be an arithmetic type");
3469     CodeGenFunction::CGFPOptionsRAII FPOptsRAII(CGF, Ops.FPFeatures);
3470     return MB.CreateScalarDiv(Ops.LHS, Ops.RHS,
3471                               Ops.Ty->hasUnsignedIntegerRepresentation());
3472   }
3473 
3474   if (Ops.LHS->getType()->isFPOrFPVectorTy()) {
3475     llvm::Value *Val;
3476     CodeGenFunction::CGFPOptionsRAII FPOptsRAII(CGF, Ops.FPFeatures);
3477     Val = Builder.CreateFDiv(Ops.LHS, Ops.RHS, "div");
3478     CGF.SetDivFPAccuracy(Val);
3479     return Val;
3480   }
3481   else if (Ops.isFixedPointOp())
3482     return EmitFixedPointBinOp(Ops);
3483   else if (Ops.Ty->hasUnsignedIntegerRepresentation())
3484     return Builder.CreateUDiv(Ops.LHS, Ops.RHS, "div");
3485   else
3486     return Builder.CreateSDiv(Ops.LHS, Ops.RHS, "div");
3487 }
3488 
3489 Value *ScalarExprEmitter::EmitRem(const BinOpInfo &Ops) {
3490   // Rem in C can't be a floating point type: C99 6.5.5p2.
3491   if ((CGF.SanOpts.has(SanitizerKind::IntegerDivideByZero) ||
3492        CGF.SanOpts.has(SanitizerKind::SignedIntegerOverflow)) &&
3493       Ops.Ty->isIntegerType() &&
3494       (Ops.mayHaveIntegerDivisionByZero() || Ops.mayHaveIntegerOverflow())) {
3495     CodeGenFunction::SanitizerScope SanScope(&CGF);
3496     llvm::Value *Zero = llvm::Constant::getNullValue(ConvertType(Ops.Ty));
3497     EmitUndefinedBehaviorIntegerDivAndRemCheck(Ops, Zero, false);
3498   }
3499 
3500   if (Ops.Ty->hasUnsignedIntegerRepresentation())
3501     return Builder.CreateURem(Ops.LHS, Ops.RHS, "rem");
3502   else
3503     return Builder.CreateSRem(Ops.LHS, Ops.RHS, "rem");
3504 }
3505 
3506 Value *ScalarExprEmitter::EmitOverflowCheckedBinOp(const BinOpInfo &Ops) {
3507   unsigned IID;
3508   unsigned OpID = 0;
3509   SanitizerHandler OverflowKind;
3510 
3511   bool isSigned = Ops.Ty->isSignedIntegerOrEnumerationType();
3512   switch (Ops.Opcode) {
3513   case BO_Add:
3514   case BO_AddAssign:
3515     OpID = 1;
3516     IID = isSigned ? llvm::Intrinsic::sadd_with_overflow :
3517                      llvm::Intrinsic::uadd_with_overflow;
3518     OverflowKind = SanitizerHandler::AddOverflow;
3519     break;
3520   case BO_Sub:
3521   case BO_SubAssign:
3522     OpID = 2;
3523     IID = isSigned ? llvm::Intrinsic::ssub_with_overflow :
3524                      llvm::Intrinsic::usub_with_overflow;
3525     OverflowKind = SanitizerHandler::SubOverflow;
3526     break;
3527   case BO_Mul:
3528   case BO_MulAssign:
3529     OpID = 3;
3530     IID = isSigned ? llvm::Intrinsic::smul_with_overflow :
3531                      llvm::Intrinsic::umul_with_overflow;
3532     OverflowKind = SanitizerHandler::MulOverflow;
3533     break;
3534   default:
3535     llvm_unreachable("Unsupported operation for overflow detection");
3536   }
3537   OpID <<= 1;
3538   if (isSigned)
3539     OpID |= 1;
3540 
3541   CodeGenFunction::SanitizerScope SanScope(&CGF);
3542   llvm::Type *opTy = CGF.CGM.getTypes().ConvertType(Ops.Ty);
3543 
3544   llvm::Function *intrinsic = CGF.CGM.getIntrinsic(IID, opTy);
3545 
3546   Value *resultAndOverflow = Builder.CreateCall(intrinsic, {Ops.LHS, Ops.RHS});
3547   Value *result = Builder.CreateExtractValue(resultAndOverflow, 0);
3548   Value *overflow = Builder.CreateExtractValue(resultAndOverflow, 1);
3549 
3550   // Handle overflow with llvm.trap if no custom handler has been specified.
3551   const std::string *handlerName =
3552     &CGF.getLangOpts().OverflowHandler;
3553   if (handlerName->empty()) {
3554     // If the signed-integer-overflow sanitizer is enabled, emit a call to its
3555     // runtime. Otherwise, this is a -ftrapv check, so just emit a trap.
3556     if (!isSigned || CGF.SanOpts.has(SanitizerKind::SignedIntegerOverflow)) {
3557       llvm::Value *NotOverflow = Builder.CreateNot(overflow);
3558       SanitizerMask Kind = isSigned ? SanitizerKind::SignedIntegerOverflow
3559                               : SanitizerKind::UnsignedIntegerOverflow;
3560       EmitBinOpCheck(std::make_pair(NotOverflow, Kind), Ops);
3561     } else
3562       CGF.EmitTrapCheck(Builder.CreateNot(overflow), OverflowKind);
3563     return result;
3564   }
3565 
3566   // Branch in case of overflow.
3567   llvm::BasicBlock *initialBB = Builder.GetInsertBlock();
3568   llvm::BasicBlock *continueBB =
3569       CGF.createBasicBlock("nooverflow", CGF.CurFn, initialBB->getNextNode());
3570   llvm::BasicBlock *overflowBB = CGF.createBasicBlock("overflow", CGF.CurFn);
3571 
3572   Builder.CreateCondBr(overflow, overflowBB, continueBB);
3573 
3574   // If an overflow handler is set, then we want to call it and then use its
3575   // result, if it returns.
3576   Builder.SetInsertPoint(overflowBB);
3577 
3578   // Get the overflow handler.
3579   llvm::Type *Int8Ty = CGF.Int8Ty;
3580   llvm::Type *argTypes[] = { CGF.Int64Ty, CGF.Int64Ty, Int8Ty, Int8Ty };
3581   llvm::FunctionType *handlerTy =
3582       llvm::FunctionType::get(CGF.Int64Ty, argTypes, true);
3583   llvm::FunctionCallee handler =
3584       CGF.CGM.CreateRuntimeFunction(handlerTy, *handlerName);
3585 
3586   // Sign extend the args to 64-bit, so that we can use the same handler for
3587   // all types of overflow.
3588   llvm::Value *lhs = Builder.CreateSExt(Ops.LHS, CGF.Int64Ty);
3589   llvm::Value *rhs = Builder.CreateSExt(Ops.RHS, CGF.Int64Ty);
3590 
3591   // Call the handler with the two arguments, the operation, and the size of
3592   // the result.
3593   llvm::Value *handlerArgs[] = {
3594     lhs,
3595     rhs,
3596     Builder.getInt8(OpID),
3597     Builder.getInt8(cast<llvm::IntegerType>(opTy)->getBitWidth())
3598   };
3599   llvm::Value *handlerResult =
3600     CGF.EmitNounwindRuntimeCall(handler, handlerArgs);
3601 
3602   // Truncate the result back to the desired size.
3603   handlerResult = Builder.CreateTrunc(handlerResult, opTy);
3604   Builder.CreateBr(continueBB);
3605 
3606   Builder.SetInsertPoint(continueBB);
3607   llvm::PHINode *phi = Builder.CreatePHI(opTy, 2);
3608   phi->addIncoming(result, initialBB);
3609   phi->addIncoming(handlerResult, overflowBB);
3610 
3611   return phi;
3612 }
3613 
3614 /// Emit pointer + index arithmetic.
3615 static Value *emitPointerArithmetic(CodeGenFunction &CGF,
3616                                     const BinOpInfo &op,
3617                                     bool isSubtraction) {
3618   // Must have binary (not unary) expr here.  Unary pointer
3619   // increment/decrement doesn't use this path.
3620   const BinaryOperator *expr = cast<BinaryOperator>(op.E);
3621 
3622   Value *pointer = op.LHS;
3623   Expr *pointerOperand = expr->getLHS();
3624   Value *index = op.RHS;
3625   Expr *indexOperand = expr->getRHS();
3626 
3627   // In a subtraction, the LHS is always the pointer.
3628   if (!isSubtraction && !pointer->getType()->isPointerTy()) {
3629     std::swap(pointer, index);
3630     std::swap(pointerOperand, indexOperand);
3631   }
3632 
3633   bool isSigned = indexOperand->getType()->isSignedIntegerOrEnumerationType();
3634 
3635   unsigned width = cast<llvm::IntegerType>(index->getType())->getBitWidth();
3636   auto &DL = CGF.CGM.getDataLayout();
3637   auto PtrTy = cast<llvm::PointerType>(pointer->getType());
3638 
3639   // Some versions of glibc and gcc use idioms (particularly in their malloc
3640   // routines) that add a pointer-sized integer (known to be a pointer value)
3641   // to a null pointer in order to cast the value back to an integer or as
3642   // part of a pointer alignment algorithm.  This is undefined behavior, but
3643   // we'd like to be able to compile programs that use it.
3644   //
3645   // Normally, we'd generate a GEP with a null-pointer base here in response
3646   // to that code, but it's also UB to dereference a pointer created that
3647   // way.  Instead (as an acknowledged hack to tolerate the idiom) we will
3648   // generate a direct cast of the integer value to a pointer.
3649   //
3650   // The idiom (p = nullptr + N) is not met if any of the following are true:
3651   //
3652   //   The operation is subtraction.
3653   //   The index is not pointer-sized.
3654   //   The pointer type is not byte-sized.
3655   //
3656   if (BinaryOperator::isNullPointerArithmeticExtension(CGF.getContext(),
3657                                                        op.Opcode,
3658                                                        expr->getLHS(),
3659                                                        expr->getRHS()))
3660     return CGF.Builder.CreateIntToPtr(index, pointer->getType());
3661 
3662   if (width != DL.getIndexTypeSizeInBits(PtrTy)) {
3663     // Zero-extend or sign-extend the pointer value according to
3664     // whether the index is signed or not.
3665     index = CGF.Builder.CreateIntCast(index, DL.getIndexType(PtrTy), isSigned,
3666                                       "idx.ext");
3667   }
3668 
3669   // If this is subtraction, negate the index.
3670   if (isSubtraction)
3671     index = CGF.Builder.CreateNeg(index, "idx.neg");
3672 
3673   if (CGF.SanOpts.has(SanitizerKind::ArrayBounds))
3674     CGF.EmitBoundsCheck(op.E, pointerOperand, index, indexOperand->getType(),
3675                         /*Accessed*/ false);
3676 
3677   const PointerType *pointerType
3678     = pointerOperand->getType()->getAs<PointerType>();
3679   if (!pointerType) {
3680     QualType objectType = pointerOperand->getType()
3681                                         ->castAs<ObjCObjectPointerType>()
3682                                         ->getPointeeType();
3683     llvm::Value *objectSize
3684       = CGF.CGM.getSize(CGF.getContext().getTypeSizeInChars(objectType));
3685 
3686     index = CGF.Builder.CreateMul(index, objectSize);
3687 
3688     Value *result =
3689         CGF.Builder.CreateGEP(CGF.Int8Ty, pointer, index, "add.ptr");
3690     return CGF.Builder.CreateBitCast(result, pointer->getType());
3691   }
3692 
3693   QualType elementType = pointerType->getPointeeType();
3694   if (const VariableArrayType *vla
3695         = CGF.getContext().getAsVariableArrayType(elementType)) {
3696     // The element count here is the total number of non-VLA elements.
3697     llvm::Value *numElements = CGF.getVLASize(vla).NumElts;
3698 
3699     // Effectively, the multiply by the VLA size is part of the GEP.
3700     // GEP indexes are signed, and scaling an index isn't permitted to
3701     // signed-overflow, so we use the same semantics for our explicit
3702     // multiply.  We suppress this if overflow is not undefined behavior.
3703     llvm::Type *elemTy = CGF.ConvertTypeForMem(vla->getElementType());
3704     if (CGF.getLangOpts().isSignedOverflowDefined()) {
3705       index = CGF.Builder.CreateMul(index, numElements, "vla.index");
3706       pointer = CGF.Builder.CreateGEP(elemTy, pointer, index, "add.ptr");
3707     } else {
3708       index = CGF.Builder.CreateNSWMul(index, numElements, "vla.index");
3709       pointer = CGF.EmitCheckedInBoundsGEP(
3710           elemTy, pointer, index, isSigned, isSubtraction, op.E->getExprLoc(),
3711           "add.ptr");
3712     }
3713     return pointer;
3714   }
3715 
3716   // Explicitly handle GNU void* and function pointer arithmetic extensions. The
3717   // GNU void* casts amount to no-ops since our void* type is i8*, but this is
3718   // future proof.
3719   llvm::Type *elemTy;
3720   if (elementType->isVoidType() || elementType->isFunctionType())
3721     elemTy = CGF.Int8Ty;
3722   else
3723     elemTy = CGF.ConvertTypeForMem(elementType);
3724 
3725   if (CGF.getLangOpts().isSignedOverflowDefined())
3726     return CGF.Builder.CreateGEP(elemTy, pointer, index, "add.ptr");
3727 
3728   return CGF.EmitCheckedInBoundsGEP(
3729       elemTy, pointer, index, isSigned, isSubtraction, op.E->getExprLoc(),
3730       "add.ptr");
3731 }
3732 
3733 // Construct an fmuladd intrinsic to represent a fused mul-add of MulOp and
3734 // Addend. Use negMul and negAdd to negate the first operand of the Mul or
3735 // the add operand respectively. This allows fmuladd to represent a*b-c, or
3736 // c-a*b. Patterns in LLVM should catch the negated forms and translate them to
3737 // efficient operations.
3738 static Value* buildFMulAdd(llvm::Instruction *MulOp, Value *Addend,
3739                            const CodeGenFunction &CGF, CGBuilderTy &Builder,
3740                            bool negMul, bool negAdd) {
3741   Value *MulOp0 = MulOp->getOperand(0);
3742   Value *MulOp1 = MulOp->getOperand(1);
3743   if (negMul)
3744     MulOp0 = Builder.CreateFNeg(MulOp0, "neg");
3745   if (negAdd)
3746     Addend = Builder.CreateFNeg(Addend, "neg");
3747 
3748   Value *FMulAdd = nullptr;
3749   if (Builder.getIsFPConstrained()) {
3750     assert(isa<llvm::ConstrainedFPIntrinsic>(MulOp) &&
3751            "Only constrained operation should be created when Builder is in FP "
3752            "constrained mode");
3753     FMulAdd = Builder.CreateConstrainedFPCall(
3754         CGF.CGM.getIntrinsic(llvm::Intrinsic::experimental_constrained_fmuladd,
3755                              Addend->getType()),
3756         {MulOp0, MulOp1, Addend});
3757   } else {
3758     FMulAdd = Builder.CreateCall(
3759         CGF.CGM.getIntrinsic(llvm::Intrinsic::fmuladd, Addend->getType()),
3760         {MulOp0, MulOp1, Addend});
3761   }
3762   MulOp->eraseFromParent();
3763 
3764   return FMulAdd;
3765 }
3766 
3767 // Check whether it would be legal to emit an fmuladd intrinsic call to
3768 // represent op and if so, build the fmuladd.
3769 //
3770 // Checks that (a) the operation is fusable, and (b) -ffp-contract=on.
3771 // Does NOT check the type of the operation - it's assumed that this function
3772 // will be called from contexts where it's known that the type is contractable.
3773 static Value* tryEmitFMulAdd(const BinOpInfo &op,
3774                          const CodeGenFunction &CGF, CGBuilderTy &Builder,
3775                          bool isSub=false) {
3776 
3777   assert((op.Opcode == BO_Add || op.Opcode == BO_AddAssign ||
3778           op.Opcode == BO_Sub || op.Opcode == BO_SubAssign) &&
3779          "Only fadd/fsub can be the root of an fmuladd.");
3780 
3781   // Check whether this op is marked as fusable.
3782   if (!op.FPFeatures.allowFPContractWithinStatement())
3783     return nullptr;
3784 
3785   Value *LHS = op.LHS;
3786   Value *RHS = op.RHS;
3787 
3788   // Peek through fneg to look for fmul. Make sure fneg has no users, and that
3789   // it is the only use of its operand.
3790   bool NegLHS = false;
3791   if (auto *LHSUnOp = dyn_cast<llvm::UnaryOperator>(LHS)) {
3792     if (LHSUnOp->getOpcode() == llvm::Instruction::FNeg &&
3793         LHSUnOp->use_empty() && LHSUnOp->getOperand(0)->hasOneUse()) {
3794       LHS = LHSUnOp->getOperand(0);
3795       NegLHS = true;
3796     }
3797   }
3798 
3799   bool NegRHS = false;
3800   if (auto *RHSUnOp = dyn_cast<llvm::UnaryOperator>(RHS)) {
3801     if (RHSUnOp->getOpcode() == llvm::Instruction::FNeg &&
3802         RHSUnOp->use_empty() && RHSUnOp->getOperand(0)->hasOneUse()) {
3803       RHS = RHSUnOp->getOperand(0);
3804       NegRHS = true;
3805     }
3806   }
3807 
3808   // We have a potentially fusable op. Look for a mul on one of the operands.
3809   // Also, make sure that the mul result isn't used directly. In that case,
3810   // there's no point creating a muladd operation.
3811   if (auto *LHSBinOp = dyn_cast<llvm::BinaryOperator>(LHS)) {
3812     if (LHSBinOp->getOpcode() == llvm::Instruction::FMul &&
3813         (LHSBinOp->use_empty() || NegLHS)) {
3814       // If we looked through fneg, erase it.
3815       if (NegLHS)
3816         cast<llvm::Instruction>(op.LHS)->eraseFromParent();
3817       return buildFMulAdd(LHSBinOp, op.RHS, CGF, Builder, NegLHS, isSub);
3818     }
3819   }
3820   if (auto *RHSBinOp = dyn_cast<llvm::BinaryOperator>(RHS)) {
3821     if (RHSBinOp->getOpcode() == llvm::Instruction::FMul &&
3822         (RHSBinOp->use_empty() || NegRHS)) {
3823       // If we looked through fneg, erase it.
3824       if (NegRHS)
3825         cast<llvm::Instruction>(op.RHS)->eraseFromParent();
3826       return buildFMulAdd(RHSBinOp, op.LHS, CGF, Builder, isSub ^ NegRHS, false);
3827     }
3828   }
3829 
3830   if (auto *LHSBinOp = dyn_cast<llvm::CallBase>(LHS)) {
3831     if (LHSBinOp->getIntrinsicID() ==
3832             llvm::Intrinsic::experimental_constrained_fmul &&
3833         (LHSBinOp->use_empty() || NegLHS)) {
3834       // If we looked through fneg, erase it.
3835       if (NegLHS)
3836         cast<llvm::Instruction>(op.LHS)->eraseFromParent();
3837       return buildFMulAdd(LHSBinOp, op.RHS, CGF, Builder, NegLHS, isSub);
3838     }
3839   }
3840   if (auto *RHSBinOp = dyn_cast<llvm::CallBase>(RHS)) {
3841     if (RHSBinOp->getIntrinsicID() ==
3842             llvm::Intrinsic::experimental_constrained_fmul &&
3843         (RHSBinOp->use_empty() || NegRHS)) {
3844       // If we looked through fneg, erase it.
3845       if (NegRHS)
3846         cast<llvm::Instruction>(op.RHS)->eraseFromParent();
3847       return buildFMulAdd(RHSBinOp, op.LHS, CGF, Builder, isSub ^ NegRHS, false);
3848     }
3849   }
3850 
3851   return nullptr;
3852 }
3853 
3854 Value *ScalarExprEmitter::EmitAdd(const BinOpInfo &op) {
3855   if (op.LHS->getType()->isPointerTy() ||
3856       op.RHS->getType()->isPointerTy())
3857     return emitPointerArithmetic(CGF, op, CodeGenFunction::NotSubtraction);
3858 
3859   if (op.Ty->isSignedIntegerOrEnumerationType()) {
3860     switch (CGF.getLangOpts().getSignedOverflowBehavior()) {
3861     case LangOptions::SOB_Defined:
3862       return Builder.CreateAdd(op.LHS, op.RHS, "add");
3863     case LangOptions::SOB_Undefined:
3864       if (!CGF.SanOpts.has(SanitizerKind::SignedIntegerOverflow))
3865         return Builder.CreateNSWAdd(op.LHS, op.RHS, "add");
3866       [[fallthrough]];
3867     case LangOptions::SOB_Trapping:
3868       if (CanElideOverflowCheck(CGF.getContext(), op))
3869         return Builder.CreateNSWAdd(op.LHS, op.RHS, "add");
3870       return EmitOverflowCheckedBinOp(op);
3871     }
3872   }
3873 
3874   // For vector and matrix adds, try to fold into a fmuladd.
3875   if (op.LHS->getType()->isFPOrFPVectorTy()) {
3876     CodeGenFunction::CGFPOptionsRAII FPOptsRAII(CGF, op.FPFeatures);
3877     // Try to form an fmuladd.
3878     if (Value *FMulAdd = tryEmitFMulAdd(op, CGF, Builder))
3879       return FMulAdd;
3880   }
3881 
3882   if (op.Ty->isConstantMatrixType()) {
3883     llvm::MatrixBuilder MB(Builder);
3884     CodeGenFunction::CGFPOptionsRAII FPOptsRAII(CGF, op.FPFeatures);
3885     return MB.CreateAdd(op.LHS, op.RHS);
3886   }
3887 
3888   if (op.Ty->isUnsignedIntegerType() &&
3889       CGF.SanOpts.has(SanitizerKind::UnsignedIntegerOverflow) &&
3890       !CanElideOverflowCheck(CGF.getContext(), op))
3891     return EmitOverflowCheckedBinOp(op);
3892 
3893   if (op.LHS->getType()->isFPOrFPVectorTy()) {
3894     CodeGenFunction::CGFPOptionsRAII FPOptsRAII(CGF, op.FPFeatures);
3895     return Builder.CreateFAdd(op.LHS, op.RHS, "add");
3896   }
3897 
3898   if (op.isFixedPointOp())
3899     return EmitFixedPointBinOp(op);
3900 
3901   return Builder.CreateAdd(op.LHS, op.RHS, "add");
3902 }
3903 
3904 /// The resulting value must be calculated with exact precision, so the operands
3905 /// may not be the same type.
3906 Value *ScalarExprEmitter::EmitFixedPointBinOp(const BinOpInfo &op) {
3907   using llvm::APSInt;
3908   using llvm::ConstantInt;
3909 
3910   // This is either a binary operation where at least one of the operands is
3911   // a fixed-point type, or a unary operation where the operand is a fixed-point
3912   // type. The result type of a binary operation is determined by
3913   // Sema::handleFixedPointConversions().
3914   QualType ResultTy = op.Ty;
3915   QualType LHSTy, RHSTy;
3916   if (const auto *BinOp = dyn_cast<BinaryOperator>(op.E)) {
3917     RHSTy = BinOp->getRHS()->getType();
3918     if (const auto *CAO = dyn_cast<CompoundAssignOperator>(BinOp)) {
3919       // For compound assignment, the effective type of the LHS at this point
3920       // is the computation LHS type, not the actual LHS type, and the final
3921       // result type is not the type of the expression but rather the
3922       // computation result type.
3923       LHSTy = CAO->getComputationLHSType();
3924       ResultTy = CAO->getComputationResultType();
3925     } else
3926       LHSTy = BinOp->getLHS()->getType();
3927   } else if (const auto *UnOp = dyn_cast<UnaryOperator>(op.E)) {
3928     LHSTy = UnOp->getSubExpr()->getType();
3929     RHSTy = UnOp->getSubExpr()->getType();
3930   }
3931   ASTContext &Ctx = CGF.getContext();
3932   Value *LHS = op.LHS;
3933   Value *RHS = op.RHS;
3934 
3935   auto LHSFixedSema = Ctx.getFixedPointSemantics(LHSTy);
3936   auto RHSFixedSema = Ctx.getFixedPointSemantics(RHSTy);
3937   auto ResultFixedSema = Ctx.getFixedPointSemantics(ResultTy);
3938   auto CommonFixedSema = LHSFixedSema.getCommonSemantics(RHSFixedSema);
3939 
3940   // Perform the actual operation.
3941   Value *Result;
3942   llvm::FixedPointBuilder<CGBuilderTy> FPBuilder(Builder);
3943   switch (op.Opcode) {
3944   case BO_AddAssign:
3945   case BO_Add:
3946     Result = FPBuilder.CreateAdd(LHS, LHSFixedSema, RHS, RHSFixedSema);
3947     break;
3948   case BO_SubAssign:
3949   case BO_Sub:
3950     Result = FPBuilder.CreateSub(LHS, LHSFixedSema, RHS, RHSFixedSema);
3951     break;
3952   case BO_MulAssign:
3953   case BO_Mul:
3954     Result = FPBuilder.CreateMul(LHS, LHSFixedSema, RHS, RHSFixedSema);
3955     break;
3956   case BO_DivAssign:
3957   case BO_Div:
3958     Result = FPBuilder.CreateDiv(LHS, LHSFixedSema, RHS, RHSFixedSema);
3959     break;
3960   case BO_ShlAssign:
3961   case BO_Shl:
3962     Result = FPBuilder.CreateShl(LHS, LHSFixedSema, RHS);
3963     break;
3964   case BO_ShrAssign:
3965   case BO_Shr:
3966     Result = FPBuilder.CreateShr(LHS, LHSFixedSema, RHS);
3967     break;
3968   case BO_LT:
3969     return FPBuilder.CreateLT(LHS, LHSFixedSema, RHS, RHSFixedSema);
3970   case BO_GT:
3971     return FPBuilder.CreateGT(LHS, LHSFixedSema, RHS, RHSFixedSema);
3972   case BO_LE:
3973     return FPBuilder.CreateLE(LHS, LHSFixedSema, RHS, RHSFixedSema);
3974   case BO_GE:
3975     return FPBuilder.CreateGE(LHS, LHSFixedSema, RHS, RHSFixedSema);
3976   case BO_EQ:
3977     // For equality operations, we assume any padding bits on unsigned types are
3978     // zero'd out. They could be overwritten through non-saturating operations
3979     // that cause overflow, but this leads to undefined behavior.
3980     return FPBuilder.CreateEQ(LHS, LHSFixedSema, RHS, RHSFixedSema);
3981   case BO_NE:
3982     return FPBuilder.CreateNE(LHS, LHSFixedSema, RHS, RHSFixedSema);
3983   case BO_Cmp:
3984   case BO_LAnd:
3985   case BO_LOr:
3986     llvm_unreachable("Found unimplemented fixed point binary operation");
3987   case BO_PtrMemD:
3988   case BO_PtrMemI:
3989   case BO_Rem:
3990   case BO_Xor:
3991   case BO_And:
3992   case BO_Or:
3993   case BO_Assign:
3994   case BO_RemAssign:
3995   case BO_AndAssign:
3996   case BO_XorAssign:
3997   case BO_OrAssign:
3998   case BO_Comma:
3999     llvm_unreachable("Found unsupported binary operation for fixed point types.");
4000   }
4001 
4002   bool IsShift = BinaryOperator::isShiftOp(op.Opcode) ||
4003                  BinaryOperator::isShiftAssignOp(op.Opcode);
4004   // Convert to the result type.
4005   return FPBuilder.CreateFixedToFixed(Result, IsShift ? LHSFixedSema
4006                                                       : CommonFixedSema,
4007                                       ResultFixedSema);
4008 }
4009 
4010 Value *ScalarExprEmitter::EmitSub(const BinOpInfo &op) {
4011   // The LHS is always a pointer if either side is.
4012   if (!op.LHS->getType()->isPointerTy()) {
4013     if (op.Ty->isSignedIntegerOrEnumerationType()) {
4014       switch (CGF.getLangOpts().getSignedOverflowBehavior()) {
4015       case LangOptions::SOB_Defined:
4016         return Builder.CreateSub(op.LHS, op.RHS, "sub");
4017       case LangOptions::SOB_Undefined:
4018         if (!CGF.SanOpts.has(SanitizerKind::SignedIntegerOverflow))
4019           return Builder.CreateNSWSub(op.LHS, op.RHS, "sub");
4020         [[fallthrough]];
4021       case LangOptions::SOB_Trapping:
4022         if (CanElideOverflowCheck(CGF.getContext(), op))
4023           return Builder.CreateNSWSub(op.LHS, op.RHS, "sub");
4024         return EmitOverflowCheckedBinOp(op);
4025       }
4026     }
4027 
4028     // For vector and matrix subs, try to fold into a fmuladd.
4029     if (op.LHS->getType()->isFPOrFPVectorTy()) {
4030       CodeGenFunction::CGFPOptionsRAII FPOptsRAII(CGF, op.FPFeatures);
4031       // Try to form an fmuladd.
4032       if (Value *FMulAdd = tryEmitFMulAdd(op, CGF, Builder, true))
4033         return FMulAdd;
4034     }
4035 
4036     if (op.Ty->isConstantMatrixType()) {
4037       llvm::MatrixBuilder MB(Builder);
4038       CodeGenFunction::CGFPOptionsRAII FPOptsRAII(CGF, op.FPFeatures);
4039       return MB.CreateSub(op.LHS, op.RHS);
4040     }
4041 
4042     if (op.Ty->isUnsignedIntegerType() &&
4043         CGF.SanOpts.has(SanitizerKind::UnsignedIntegerOverflow) &&
4044         !CanElideOverflowCheck(CGF.getContext(), op))
4045       return EmitOverflowCheckedBinOp(op);
4046 
4047     if (op.LHS->getType()->isFPOrFPVectorTy()) {
4048       CodeGenFunction::CGFPOptionsRAII FPOptsRAII(CGF, op.FPFeatures);
4049       return Builder.CreateFSub(op.LHS, op.RHS, "sub");
4050     }
4051 
4052     if (op.isFixedPointOp())
4053       return EmitFixedPointBinOp(op);
4054 
4055     return Builder.CreateSub(op.LHS, op.RHS, "sub");
4056   }
4057 
4058   // If the RHS is not a pointer, then we have normal pointer
4059   // arithmetic.
4060   if (!op.RHS->getType()->isPointerTy())
4061     return emitPointerArithmetic(CGF, op, CodeGenFunction::IsSubtraction);
4062 
4063   // Otherwise, this is a pointer subtraction.
4064 
4065   // Do the raw subtraction part.
4066   llvm::Value *LHS
4067     = Builder.CreatePtrToInt(op.LHS, CGF.PtrDiffTy, "sub.ptr.lhs.cast");
4068   llvm::Value *RHS
4069     = Builder.CreatePtrToInt(op.RHS, CGF.PtrDiffTy, "sub.ptr.rhs.cast");
4070   Value *diffInChars = Builder.CreateSub(LHS, RHS, "sub.ptr.sub");
4071 
4072   // Okay, figure out the element size.
4073   const BinaryOperator *expr = cast<BinaryOperator>(op.E);
4074   QualType elementType = expr->getLHS()->getType()->getPointeeType();
4075 
4076   llvm::Value *divisor = nullptr;
4077 
4078   // For a variable-length array, this is going to be non-constant.
4079   if (const VariableArrayType *vla
4080         = CGF.getContext().getAsVariableArrayType(elementType)) {
4081     auto VlaSize = CGF.getVLASize(vla);
4082     elementType = VlaSize.Type;
4083     divisor = VlaSize.NumElts;
4084 
4085     // Scale the number of non-VLA elements by the non-VLA element size.
4086     CharUnits eltSize = CGF.getContext().getTypeSizeInChars(elementType);
4087     if (!eltSize.isOne())
4088       divisor = CGF.Builder.CreateNUWMul(CGF.CGM.getSize(eltSize), divisor);
4089 
4090   // For everything elese, we can just compute it, safe in the
4091   // assumption that Sema won't let anything through that we can't
4092   // safely compute the size of.
4093   } else {
4094     CharUnits elementSize;
4095     // Handle GCC extension for pointer arithmetic on void* and
4096     // function pointer types.
4097     if (elementType->isVoidType() || elementType->isFunctionType())
4098       elementSize = CharUnits::One();
4099     else
4100       elementSize = CGF.getContext().getTypeSizeInChars(elementType);
4101 
4102     // Don't even emit the divide for element size of 1.
4103     if (elementSize.isOne())
4104       return diffInChars;
4105 
4106     divisor = CGF.CGM.getSize(elementSize);
4107   }
4108 
4109   // Otherwise, do a full sdiv. This uses the "exact" form of sdiv, since
4110   // pointer difference in C is only defined in the case where both operands
4111   // are pointing to elements of an array.
4112   return Builder.CreateExactSDiv(diffInChars, divisor, "sub.ptr.div");
4113 }
4114 
4115 Value *ScalarExprEmitter::GetWidthMinusOneValue(Value* LHS,Value* RHS) {
4116   llvm::IntegerType *Ty;
4117   if (llvm::VectorType *VT = dyn_cast<llvm::VectorType>(LHS->getType()))
4118     Ty = cast<llvm::IntegerType>(VT->getElementType());
4119   else
4120     Ty = cast<llvm::IntegerType>(LHS->getType());
4121   return llvm::ConstantInt::get(RHS->getType(), Ty->getBitWidth() - 1);
4122 }
4123 
4124 Value *ScalarExprEmitter::ConstrainShiftValue(Value *LHS, Value *RHS,
4125                                               const Twine &Name) {
4126   llvm::IntegerType *Ty;
4127   if (auto *VT = dyn_cast<llvm::VectorType>(LHS->getType()))
4128     Ty = cast<llvm::IntegerType>(VT->getElementType());
4129   else
4130     Ty = cast<llvm::IntegerType>(LHS->getType());
4131 
4132   if (llvm::isPowerOf2_64(Ty->getBitWidth()))
4133         return Builder.CreateAnd(RHS, GetWidthMinusOneValue(LHS, RHS), Name);
4134 
4135   return Builder.CreateURem(
4136       RHS, llvm::ConstantInt::get(RHS->getType(), Ty->getBitWidth()), Name);
4137 }
4138 
4139 Value *ScalarExprEmitter::EmitShl(const BinOpInfo &Ops) {
4140   // TODO: This misses out on the sanitizer check below.
4141   if (Ops.isFixedPointOp())
4142     return EmitFixedPointBinOp(Ops);
4143 
4144   // LLVM requires the LHS and RHS to be the same type: promote or truncate the
4145   // RHS to the same size as the LHS.
4146   Value *RHS = Ops.RHS;
4147   if (Ops.LHS->getType() != RHS->getType())
4148     RHS = Builder.CreateIntCast(RHS, Ops.LHS->getType(), false, "sh_prom");
4149 
4150   bool SanitizeSignedBase = CGF.SanOpts.has(SanitizerKind::ShiftBase) &&
4151                             Ops.Ty->hasSignedIntegerRepresentation() &&
4152                             !CGF.getLangOpts().isSignedOverflowDefined() &&
4153                             !CGF.getLangOpts().CPlusPlus20;
4154   bool SanitizeUnsignedBase =
4155       CGF.SanOpts.has(SanitizerKind::UnsignedShiftBase) &&
4156       Ops.Ty->hasUnsignedIntegerRepresentation();
4157   bool SanitizeBase = SanitizeSignedBase || SanitizeUnsignedBase;
4158   bool SanitizeExponent = CGF.SanOpts.has(SanitizerKind::ShiftExponent);
4159   // OpenCL 6.3j: shift values are effectively % word size of LHS.
4160   if (CGF.getLangOpts().OpenCL)
4161     RHS = ConstrainShiftValue(Ops.LHS, RHS, "shl.mask");
4162   else if ((SanitizeBase || SanitizeExponent) &&
4163            isa<llvm::IntegerType>(Ops.LHS->getType())) {
4164     CodeGenFunction::SanitizerScope SanScope(&CGF);
4165     SmallVector<std::pair<Value *, SanitizerMask>, 2> Checks;
4166     llvm::Value *WidthMinusOne = GetWidthMinusOneValue(Ops.LHS, Ops.RHS);
4167     llvm::Value *ValidExponent = Builder.CreateICmpULE(Ops.RHS, WidthMinusOne);
4168 
4169     if (SanitizeExponent) {
4170       Checks.push_back(
4171           std::make_pair(ValidExponent, SanitizerKind::ShiftExponent));
4172     }
4173 
4174     if (SanitizeBase) {
4175       // Check whether we are shifting any non-zero bits off the top of the
4176       // integer. We only emit this check if exponent is valid - otherwise
4177       // instructions below will have undefined behavior themselves.
4178       llvm::BasicBlock *Orig = Builder.GetInsertBlock();
4179       llvm::BasicBlock *Cont = CGF.createBasicBlock("cont");
4180       llvm::BasicBlock *CheckShiftBase = CGF.createBasicBlock("check");
4181       Builder.CreateCondBr(ValidExponent, CheckShiftBase, Cont);
4182       llvm::Value *PromotedWidthMinusOne =
4183           (RHS == Ops.RHS) ? WidthMinusOne
4184                            : GetWidthMinusOneValue(Ops.LHS, RHS);
4185       CGF.EmitBlock(CheckShiftBase);
4186       llvm::Value *BitsShiftedOff = Builder.CreateLShr(
4187           Ops.LHS, Builder.CreateSub(PromotedWidthMinusOne, RHS, "shl.zeros",
4188                                      /*NUW*/ true, /*NSW*/ true),
4189           "shl.check");
4190       if (SanitizeUnsignedBase || CGF.getLangOpts().CPlusPlus) {
4191         // In C99, we are not permitted to shift a 1 bit into the sign bit.
4192         // Under C++11's rules, shifting a 1 bit into the sign bit is
4193         // OK, but shifting a 1 bit out of it is not. (C89 and C++03 don't
4194         // define signed left shifts, so we use the C99 and C++11 rules there).
4195         // Unsigned shifts can always shift into the top bit.
4196         llvm::Value *One = llvm::ConstantInt::get(BitsShiftedOff->getType(), 1);
4197         BitsShiftedOff = Builder.CreateLShr(BitsShiftedOff, One);
4198       }
4199       llvm::Value *Zero = llvm::ConstantInt::get(BitsShiftedOff->getType(), 0);
4200       llvm::Value *ValidBase = Builder.CreateICmpEQ(BitsShiftedOff, Zero);
4201       CGF.EmitBlock(Cont);
4202       llvm::PHINode *BaseCheck = Builder.CreatePHI(ValidBase->getType(), 2);
4203       BaseCheck->addIncoming(Builder.getTrue(), Orig);
4204       BaseCheck->addIncoming(ValidBase, CheckShiftBase);
4205       Checks.push_back(std::make_pair(
4206           BaseCheck, SanitizeSignedBase ? SanitizerKind::ShiftBase
4207                                         : SanitizerKind::UnsignedShiftBase));
4208     }
4209 
4210     assert(!Checks.empty());
4211     EmitBinOpCheck(Checks, Ops);
4212   }
4213 
4214   return Builder.CreateShl(Ops.LHS, RHS, "shl");
4215 }
4216 
4217 Value *ScalarExprEmitter::EmitShr(const BinOpInfo &Ops) {
4218   // TODO: This misses out on the sanitizer check below.
4219   if (Ops.isFixedPointOp())
4220     return EmitFixedPointBinOp(Ops);
4221 
4222   // LLVM requires the LHS and RHS to be the same type: promote or truncate the
4223   // RHS to the same size as the LHS.
4224   Value *RHS = Ops.RHS;
4225   if (Ops.LHS->getType() != RHS->getType())
4226     RHS = Builder.CreateIntCast(RHS, Ops.LHS->getType(), false, "sh_prom");
4227 
4228   // OpenCL 6.3j: shift values are effectively % word size of LHS.
4229   if (CGF.getLangOpts().OpenCL)
4230     RHS = ConstrainShiftValue(Ops.LHS, RHS, "shr.mask");
4231   else if (CGF.SanOpts.has(SanitizerKind::ShiftExponent) &&
4232            isa<llvm::IntegerType>(Ops.LHS->getType())) {
4233     CodeGenFunction::SanitizerScope SanScope(&CGF);
4234     llvm::Value *Valid =
4235         Builder.CreateICmpULE(RHS, GetWidthMinusOneValue(Ops.LHS, RHS));
4236     EmitBinOpCheck(std::make_pair(Valid, SanitizerKind::ShiftExponent), Ops);
4237   }
4238 
4239   if (Ops.Ty->hasUnsignedIntegerRepresentation())
4240     return Builder.CreateLShr(Ops.LHS, RHS, "shr");
4241   return Builder.CreateAShr(Ops.LHS, RHS, "shr");
4242 }
4243 
4244 enum IntrinsicType { VCMPEQ, VCMPGT };
4245 // return corresponding comparison intrinsic for given vector type
4246 static llvm::Intrinsic::ID GetIntrinsic(IntrinsicType IT,
4247                                         BuiltinType::Kind ElemKind) {
4248   switch (ElemKind) {
4249   default: llvm_unreachable("unexpected element type");
4250   case BuiltinType::Char_U:
4251   case BuiltinType::UChar:
4252     return (IT == VCMPEQ) ? llvm::Intrinsic::ppc_altivec_vcmpequb_p :
4253                             llvm::Intrinsic::ppc_altivec_vcmpgtub_p;
4254   case BuiltinType::Char_S:
4255   case BuiltinType::SChar:
4256     return (IT == VCMPEQ) ? llvm::Intrinsic::ppc_altivec_vcmpequb_p :
4257                             llvm::Intrinsic::ppc_altivec_vcmpgtsb_p;
4258   case BuiltinType::UShort:
4259     return (IT == VCMPEQ) ? llvm::Intrinsic::ppc_altivec_vcmpequh_p :
4260                             llvm::Intrinsic::ppc_altivec_vcmpgtuh_p;
4261   case BuiltinType::Short:
4262     return (IT == VCMPEQ) ? llvm::Intrinsic::ppc_altivec_vcmpequh_p :
4263                             llvm::Intrinsic::ppc_altivec_vcmpgtsh_p;
4264   case BuiltinType::UInt:
4265     return (IT == VCMPEQ) ? llvm::Intrinsic::ppc_altivec_vcmpequw_p :
4266                             llvm::Intrinsic::ppc_altivec_vcmpgtuw_p;
4267   case BuiltinType::Int:
4268     return (IT == VCMPEQ) ? llvm::Intrinsic::ppc_altivec_vcmpequw_p :
4269                             llvm::Intrinsic::ppc_altivec_vcmpgtsw_p;
4270   case BuiltinType::ULong:
4271   case BuiltinType::ULongLong:
4272     return (IT == VCMPEQ) ? llvm::Intrinsic::ppc_altivec_vcmpequd_p :
4273                             llvm::Intrinsic::ppc_altivec_vcmpgtud_p;
4274   case BuiltinType::Long:
4275   case BuiltinType::LongLong:
4276     return (IT == VCMPEQ) ? llvm::Intrinsic::ppc_altivec_vcmpequd_p :
4277                             llvm::Intrinsic::ppc_altivec_vcmpgtsd_p;
4278   case BuiltinType::Float:
4279     return (IT == VCMPEQ) ? llvm::Intrinsic::ppc_altivec_vcmpeqfp_p :
4280                             llvm::Intrinsic::ppc_altivec_vcmpgtfp_p;
4281   case BuiltinType::Double:
4282     return (IT == VCMPEQ) ? llvm::Intrinsic::ppc_vsx_xvcmpeqdp_p :
4283                             llvm::Intrinsic::ppc_vsx_xvcmpgtdp_p;
4284   case BuiltinType::UInt128:
4285     return (IT == VCMPEQ) ? llvm::Intrinsic::ppc_altivec_vcmpequq_p
4286                           : llvm::Intrinsic::ppc_altivec_vcmpgtuq_p;
4287   case BuiltinType::Int128:
4288     return (IT == VCMPEQ) ? llvm::Intrinsic::ppc_altivec_vcmpequq_p
4289                           : llvm::Intrinsic::ppc_altivec_vcmpgtsq_p;
4290   }
4291 }
4292 
4293 Value *ScalarExprEmitter::EmitCompare(const BinaryOperator *E,
4294                                       llvm::CmpInst::Predicate UICmpOpc,
4295                                       llvm::CmpInst::Predicate SICmpOpc,
4296                                       llvm::CmpInst::Predicate FCmpOpc,
4297                                       bool IsSignaling) {
4298   TestAndClearIgnoreResultAssign();
4299   Value *Result;
4300   QualType LHSTy = E->getLHS()->getType();
4301   QualType RHSTy = E->getRHS()->getType();
4302   if (const MemberPointerType *MPT = LHSTy->getAs<MemberPointerType>()) {
4303     assert(E->getOpcode() == BO_EQ ||
4304            E->getOpcode() == BO_NE);
4305     Value *LHS = CGF.EmitScalarExpr(E->getLHS());
4306     Value *RHS = CGF.EmitScalarExpr(E->getRHS());
4307     Result = CGF.CGM.getCXXABI().EmitMemberPointerComparison(
4308                    CGF, LHS, RHS, MPT, E->getOpcode() == BO_NE);
4309   } else if (!LHSTy->isAnyComplexType() && !RHSTy->isAnyComplexType()) {
4310     BinOpInfo BOInfo = EmitBinOps(E);
4311     Value *LHS = BOInfo.LHS;
4312     Value *RHS = BOInfo.RHS;
4313 
4314     // If AltiVec, the comparison results in a numeric type, so we use
4315     // intrinsics comparing vectors and giving 0 or 1 as a result
4316     if (LHSTy->isVectorType() && !E->getType()->isVectorType()) {
4317       // constants for mapping CR6 register bits to predicate result
4318       enum { CR6_EQ=0, CR6_EQ_REV, CR6_LT, CR6_LT_REV } CR6;
4319 
4320       llvm::Intrinsic::ID ID = llvm::Intrinsic::not_intrinsic;
4321 
4322       // in several cases vector arguments order will be reversed
4323       Value *FirstVecArg = LHS,
4324             *SecondVecArg = RHS;
4325 
4326       QualType ElTy = LHSTy->castAs<VectorType>()->getElementType();
4327       BuiltinType::Kind ElementKind = ElTy->castAs<BuiltinType>()->getKind();
4328 
4329       switch(E->getOpcode()) {
4330       default: llvm_unreachable("is not a comparison operation");
4331       case BO_EQ:
4332         CR6 = CR6_LT;
4333         ID = GetIntrinsic(VCMPEQ, ElementKind);
4334         break;
4335       case BO_NE:
4336         CR6 = CR6_EQ;
4337         ID = GetIntrinsic(VCMPEQ, ElementKind);
4338         break;
4339       case BO_LT:
4340         CR6 = CR6_LT;
4341         ID = GetIntrinsic(VCMPGT, ElementKind);
4342         std::swap(FirstVecArg, SecondVecArg);
4343         break;
4344       case BO_GT:
4345         CR6 = CR6_LT;
4346         ID = GetIntrinsic(VCMPGT, ElementKind);
4347         break;
4348       case BO_LE:
4349         if (ElementKind == BuiltinType::Float) {
4350           CR6 = CR6_LT;
4351           ID = llvm::Intrinsic::ppc_altivec_vcmpgefp_p;
4352           std::swap(FirstVecArg, SecondVecArg);
4353         }
4354         else {
4355           CR6 = CR6_EQ;
4356           ID = GetIntrinsic(VCMPGT, ElementKind);
4357         }
4358         break;
4359       case BO_GE:
4360         if (ElementKind == BuiltinType::Float) {
4361           CR6 = CR6_LT;
4362           ID = llvm::Intrinsic::ppc_altivec_vcmpgefp_p;
4363         }
4364         else {
4365           CR6 = CR6_EQ;
4366           ID = GetIntrinsic(VCMPGT, ElementKind);
4367           std::swap(FirstVecArg, SecondVecArg);
4368         }
4369         break;
4370       }
4371 
4372       Value *CR6Param = Builder.getInt32(CR6);
4373       llvm::Function *F = CGF.CGM.getIntrinsic(ID);
4374       Result = Builder.CreateCall(F, {CR6Param, FirstVecArg, SecondVecArg});
4375 
4376       // The result type of intrinsic may not be same as E->getType().
4377       // If E->getType() is not BoolTy, EmitScalarConversion will do the
4378       // conversion work. If E->getType() is BoolTy, EmitScalarConversion will
4379       // do nothing, if ResultTy is not i1 at the same time, it will cause
4380       // crash later.
4381       llvm::IntegerType *ResultTy = cast<llvm::IntegerType>(Result->getType());
4382       if (ResultTy->getBitWidth() > 1 &&
4383           E->getType() == CGF.getContext().BoolTy)
4384         Result = Builder.CreateTrunc(Result, Builder.getInt1Ty());
4385       return EmitScalarConversion(Result, CGF.getContext().BoolTy, E->getType(),
4386                                   E->getExprLoc());
4387     }
4388 
4389     if (BOInfo.isFixedPointOp()) {
4390       Result = EmitFixedPointBinOp(BOInfo);
4391     } else if (LHS->getType()->isFPOrFPVectorTy()) {
4392       CodeGenFunction::CGFPOptionsRAII FPOptsRAII(CGF, BOInfo.FPFeatures);
4393       if (!IsSignaling)
4394         Result = Builder.CreateFCmp(FCmpOpc, LHS, RHS, "cmp");
4395       else
4396         Result = Builder.CreateFCmpS(FCmpOpc, LHS, RHS, "cmp");
4397     } else if (LHSTy->hasSignedIntegerRepresentation()) {
4398       Result = Builder.CreateICmp(SICmpOpc, LHS, RHS, "cmp");
4399     } else {
4400       // Unsigned integers and pointers.
4401 
4402       if (CGF.CGM.getCodeGenOpts().StrictVTablePointers &&
4403           !isa<llvm::ConstantPointerNull>(LHS) &&
4404           !isa<llvm::ConstantPointerNull>(RHS)) {
4405 
4406         // Dynamic information is required to be stripped for comparisons,
4407         // because it could leak the dynamic information.  Based on comparisons
4408         // of pointers to dynamic objects, the optimizer can replace one pointer
4409         // with another, which might be incorrect in presence of invariant
4410         // groups. Comparison with null is safe because null does not carry any
4411         // dynamic information.
4412         if (LHSTy.mayBeDynamicClass())
4413           LHS = Builder.CreateStripInvariantGroup(LHS);
4414         if (RHSTy.mayBeDynamicClass())
4415           RHS = Builder.CreateStripInvariantGroup(RHS);
4416       }
4417 
4418       Result = Builder.CreateICmp(UICmpOpc, LHS, RHS, "cmp");
4419     }
4420 
4421     // If this is a vector comparison, sign extend the result to the appropriate
4422     // vector integer type and return it (don't convert to bool).
4423     if (LHSTy->isVectorType())
4424       return Builder.CreateSExt(Result, ConvertType(E->getType()), "sext");
4425 
4426   } else {
4427     // Complex Comparison: can only be an equality comparison.
4428     CodeGenFunction::ComplexPairTy LHS, RHS;
4429     QualType CETy;
4430     if (auto *CTy = LHSTy->getAs<ComplexType>()) {
4431       LHS = CGF.EmitComplexExpr(E->getLHS());
4432       CETy = CTy->getElementType();
4433     } else {
4434       LHS.first = Visit(E->getLHS());
4435       LHS.second = llvm::Constant::getNullValue(LHS.first->getType());
4436       CETy = LHSTy;
4437     }
4438     if (auto *CTy = RHSTy->getAs<ComplexType>()) {
4439       RHS = CGF.EmitComplexExpr(E->getRHS());
4440       assert(CGF.getContext().hasSameUnqualifiedType(CETy,
4441                                                      CTy->getElementType()) &&
4442              "The element types must always match.");
4443       (void)CTy;
4444     } else {
4445       RHS.first = Visit(E->getRHS());
4446       RHS.second = llvm::Constant::getNullValue(RHS.first->getType());
4447       assert(CGF.getContext().hasSameUnqualifiedType(CETy, RHSTy) &&
4448              "The element types must always match.");
4449     }
4450 
4451     Value *ResultR, *ResultI;
4452     if (CETy->isRealFloatingType()) {
4453       // As complex comparisons can only be equality comparisons, they
4454       // are never signaling comparisons.
4455       ResultR = Builder.CreateFCmp(FCmpOpc, LHS.first, RHS.first, "cmp.r");
4456       ResultI = Builder.CreateFCmp(FCmpOpc, LHS.second, RHS.second, "cmp.i");
4457     } else {
4458       // Complex comparisons can only be equality comparisons.  As such, signed
4459       // and unsigned opcodes are the same.
4460       ResultR = Builder.CreateICmp(UICmpOpc, LHS.first, RHS.first, "cmp.r");
4461       ResultI = Builder.CreateICmp(UICmpOpc, LHS.second, RHS.second, "cmp.i");
4462     }
4463 
4464     if (E->getOpcode() == BO_EQ) {
4465       Result = Builder.CreateAnd(ResultR, ResultI, "and.ri");
4466     } else {
4467       assert(E->getOpcode() == BO_NE &&
4468              "Complex comparison other than == or != ?");
4469       Result = Builder.CreateOr(ResultR, ResultI, "or.ri");
4470     }
4471   }
4472 
4473   return EmitScalarConversion(Result, CGF.getContext().BoolTy, E->getType(),
4474                               E->getExprLoc());
4475 }
4476 
4477 Value *ScalarExprEmitter::VisitBinAssign(const BinaryOperator *E) {
4478   bool Ignore = TestAndClearIgnoreResultAssign();
4479 
4480   Value *RHS;
4481   LValue LHS;
4482 
4483   switch (E->getLHS()->getType().getObjCLifetime()) {
4484   case Qualifiers::OCL_Strong:
4485     std::tie(LHS, RHS) = CGF.EmitARCStoreStrong(E, Ignore);
4486     break;
4487 
4488   case Qualifiers::OCL_Autoreleasing:
4489     std::tie(LHS, RHS) = CGF.EmitARCStoreAutoreleasing(E);
4490     break;
4491 
4492   case Qualifiers::OCL_ExplicitNone:
4493     std::tie(LHS, RHS) = CGF.EmitARCStoreUnsafeUnretained(E, Ignore);
4494     break;
4495 
4496   case Qualifiers::OCL_Weak:
4497     RHS = Visit(E->getRHS());
4498     LHS = EmitCheckedLValue(E->getLHS(), CodeGenFunction::TCK_Store);
4499     RHS = CGF.EmitARCStoreWeak(LHS.getAddress(CGF), RHS, Ignore);
4500     break;
4501 
4502   case Qualifiers::OCL_None:
4503     // __block variables need to have the rhs evaluated first, plus
4504     // this should improve codegen just a little.
4505     RHS = Visit(E->getRHS());
4506     LHS = EmitCheckedLValue(E->getLHS(), CodeGenFunction::TCK_Store);
4507 
4508     // Store the value into the LHS.  Bit-fields are handled specially
4509     // because the result is altered by the store, i.e., [C99 6.5.16p1]
4510     // 'An assignment expression has the value of the left operand after
4511     // the assignment...'.
4512     if (LHS.isBitField()) {
4513       CGF.EmitStoreThroughBitfieldLValue(RValue::get(RHS), LHS, &RHS);
4514     } else {
4515       CGF.EmitNullabilityCheck(LHS, RHS, E->getExprLoc());
4516       CGF.EmitStoreThroughLValue(RValue::get(RHS), LHS);
4517     }
4518   }
4519 
4520   // If the result is clearly ignored, return now.
4521   if (Ignore)
4522     return nullptr;
4523 
4524   // The result of an assignment in C is the assigned r-value.
4525   if (!CGF.getLangOpts().CPlusPlus)
4526     return RHS;
4527 
4528   // If the lvalue is non-volatile, return the computed value of the assignment.
4529   if (!LHS.isVolatileQualified())
4530     return RHS;
4531 
4532   // Otherwise, reload the value.
4533   return EmitLoadOfLValue(LHS, E->getExprLoc());
4534 }
4535 
4536 Value *ScalarExprEmitter::VisitBinLAnd(const BinaryOperator *E) {
4537   // Perform vector logical and on comparisons with zero vectors.
4538   if (E->getType()->isVectorType()) {
4539     CGF.incrementProfileCounter(E);
4540 
4541     Value *LHS = Visit(E->getLHS());
4542     Value *RHS = Visit(E->getRHS());
4543     Value *Zero = llvm::ConstantAggregateZero::get(LHS->getType());
4544     if (LHS->getType()->isFPOrFPVectorTy()) {
4545       CodeGenFunction::CGFPOptionsRAII FPOptsRAII(
4546           CGF, E->getFPFeaturesInEffect(CGF.getLangOpts()));
4547       LHS = Builder.CreateFCmp(llvm::CmpInst::FCMP_UNE, LHS, Zero, "cmp");
4548       RHS = Builder.CreateFCmp(llvm::CmpInst::FCMP_UNE, RHS, Zero, "cmp");
4549     } else {
4550       LHS = Builder.CreateICmp(llvm::CmpInst::ICMP_NE, LHS, Zero, "cmp");
4551       RHS = Builder.CreateICmp(llvm::CmpInst::ICMP_NE, RHS, Zero, "cmp");
4552     }
4553     Value *And = Builder.CreateAnd(LHS, RHS);
4554     return Builder.CreateSExt(And, ConvertType(E->getType()), "sext");
4555   }
4556 
4557   bool InstrumentRegions = CGF.CGM.getCodeGenOpts().hasProfileClangInstr();
4558   llvm::Type *ResTy = ConvertType(E->getType());
4559 
4560   // If we have 0 && RHS, see if we can elide RHS, if so, just return 0.
4561   // If we have 1 && X, just emit X without inserting the control flow.
4562   bool LHSCondVal;
4563   if (CGF.ConstantFoldsToSimpleInteger(E->getLHS(), LHSCondVal)) {
4564     if (LHSCondVal) { // If we have 1 && X, just emit X.
4565       CGF.incrementProfileCounter(E);
4566 
4567       // If the top of the logical operator nest, reset the MCDC temp to 0.
4568       if (CGF.MCDCLogOpStack.empty())
4569         CGF.maybeResetMCDCCondBitmap(E);
4570 
4571       CGF.MCDCLogOpStack.push_back(E);
4572 
4573       Value *RHSCond = CGF.EvaluateExprAsBool(E->getRHS());
4574 
4575       // If we're generating for profiling or coverage, generate a branch to a
4576       // block that increments the RHS counter needed to track branch condition
4577       // coverage. In this case, use "FBlock" as both the final "TrueBlock" and
4578       // "FalseBlock" after the increment is done.
4579       if (InstrumentRegions &&
4580           CodeGenFunction::isInstrumentedCondition(E->getRHS())) {
4581         CGF.maybeUpdateMCDCCondBitmap(E->getRHS(), RHSCond);
4582         llvm::BasicBlock *FBlock = CGF.createBasicBlock("land.end");
4583         llvm::BasicBlock *RHSBlockCnt = CGF.createBasicBlock("land.rhscnt");
4584         Builder.CreateCondBr(RHSCond, RHSBlockCnt, FBlock);
4585         CGF.EmitBlock(RHSBlockCnt);
4586         CGF.incrementProfileCounter(E->getRHS());
4587         CGF.EmitBranch(FBlock);
4588         CGF.EmitBlock(FBlock);
4589       }
4590 
4591       CGF.MCDCLogOpStack.pop_back();
4592       // If the top of the logical operator nest, update the MCDC bitmap.
4593       if (CGF.MCDCLogOpStack.empty())
4594         CGF.maybeUpdateMCDCTestVectorBitmap(E);
4595 
4596       // ZExt result to int or bool.
4597       return Builder.CreateZExtOrBitCast(RHSCond, ResTy, "land.ext");
4598     }
4599 
4600     // 0 && RHS: If it is safe, just elide the RHS, and return 0/false.
4601     if (!CGF.ContainsLabel(E->getRHS()))
4602       return llvm::Constant::getNullValue(ResTy);
4603   }
4604 
4605   // If the top of the logical operator nest, reset the MCDC temp to 0.
4606   if (CGF.MCDCLogOpStack.empty())
4607     CGF.maybeResetMCDCCondBitmap(E);
4608 
4609   CGF.MCDCLogOpStack.push_back(E);
4610 
4611   llvm::BasicBlock *ContBlock = CGF.createBasicBlock("land.end");
4612   llvm::BasicBlock *RHSBlock  = CGF.createBasicBlock("land.rhs");
4613 
4614   CodeGenFunction::ConditionalEvaluation eval(CGF);
4615 
4616   // Branch on the LHS first.  If it is false, go to the failure (cont) block.
4617   CGF.EmitBranchOnBoolExpr(E->getLHS(), RHSBlock, ContBlock,
4618                            CGF.getProfileCount(E->getRHS()));
4619 
4620   // Any edges into the ContBlock are now from an (indeterminate number of)
4621   // edges from this first condition.  All of these values will be false.  Start
4622   // setting up the PHI node in the Cont Block for this.
4623   llvm::PHINode *PN = llvm::PHINode::Create(llvm::Type::getInt1Ty(VMContext), 2,
4624                                             "", ContBlock);
4625   for (llvm::pred_iterator PI = pred_begin(ContBlock), PE = pred_end(ContBlock);
4626        PI != PE; ++PI)
4627     PN->addIncoming(llvm::ConstantInt::getFalse(VMContext), *PI);
4628 
4629   eval.begin(CGF);
4630   CGF.EmitBlock(RHSBlock);
4631   CGF.incrementProfileCounter(E);
4632   Value *RHSCond = CGF.EvaluateExprAsBool(E->getRHS());
4633   eval.end(CGF);
4634 
4635   // Reaquire the RHS block, as there may be subblocks inserted.
4636   RHSBlock = Builder.GetInsertBlock();
4637 
4638   // If we're generating for profiling or coverage, generate a branch on the
4639   // RHS to a block that increments the RHS true counter needed to track branch
4640   // condition coverage.
4641   if (InstrumentRegions &&
4642       CodeGenFunction::isInstrumentedCondition(E->getRHS())) {
4643     CGF.maybeUpdateMCDCCondBitmap(E->getRHS(), RHSCond);
4644     llvm::BasicBlock *RHSBlockCnt = CGF.createBasicBlock("land.rhscnt");
4645     Builder.CreateCondBr(RHSCond, RHSBlockCnt, ContBlock);
4646     CGF.EmitBlock(RHSBlockCnt);
4647     CGF.incrementProfileCounter(E->getRHS());
4648     CGF.EmitBranch(ContBlock);
4649     PN->addIncoming(RHSCond, RHSBlockCnt);
4650   }
4651 
4652   // Emit an unconditional branch from this block to ContBlock.
4653   {
4654     // There is no need to emit line number for unconditional branch.
4655     auto NL = ApplyDebugLocation::CreateEmpty(CGF);
4656     CGF.EmitBlock(ContBlock);
4657   }
4658   // Insert an entry into the phi node for the edge with the value of RHSCond.
4659   PN->addIncoming(RHSCond, RHSBlock);
4660 
4661   CGF.MCDCLogOpStack.pop_back();
4662   // If the top of the logical operator nest, update the MCDC bitmap.
4663   if (CGF.MCDCLogOpStack.empty())
4664     CGF.maybeUpdateMCDCTestVectorBitmap(E);
4665 
4666   // Artificial location to preserve the scope information
4667   {
4668     auto NL = ApplyDebugLocation::CreateArtificial(CGF);
4669     PN->setDebugLoc(Builder.getCurrentDebugLocation());
4670   }
4671 
4672   // ZExt result to int.
4673   return Builder.CreateZExtOrBitCast(PN, ResTy, "land.ext");
4674 }
4675 
4676 Value *ScalarExprEmitter::VisitBinLOr(const BinaryOperator *E) {
4677   // Perform vector logical or on comparisons with zero vectors.
4678   if (E->getType()->isVectorType()) {
4679     CGF.incrementProfileCounter(E);
4680 
4681     Value *LHS = Visit(E->getLHS());
4682     Value *RHS = Visit(E->getRHS());
4683     Value *Zero = llvm::ConstantAggregateZero::get(LHS->getType());
4684     if (LHS->getType()->isFPOrFPVectorTy()) {
4685       CodeGenFunction::CGFPOptionsRAII FPOptsRAII(
4686           CGF, E->getFPFeaturesInEffect(CGF.getLangOpts()));
4687       LHS = Builder.CreateFCmp(llvm::CmpInst::FCMP_UNE, LHS, Zero, "cmp");
4688       RHS = Builder.CreateFCmp(llvm::CmpInst::FCMP_UNE, RHS, Zero, "cmp");
4689     } else {
4690       LHS = Builder.CreateICmp(llvm::CmpInst::ICMP_NE, LHS, Zero, "cmp");
4691       RHS = Builder.CreateICmp(llvm::CmpInst::ICMP_NE, RHS, Zero, "cmp");
4692     }
4693     Value *Or = Builder.CreateOr(LHS, RHS);
4694     return Builder.CreateSExt(Or, ConvertType(E->getType()), "sext");
4695   }
4696 
4697   bool InstrumentRegions = CGF.CGM.getCodeGenOpts().hasProfileClangInstr();
4698   llvm::Type *ResTy = ConvertType(E->getType());
4699 
4700   // If we have 1 || RHS, see if we can elide RHS, if so, just return 1.
4701   // If we have 0 || X, just emit X without inserting the control flow.
4702   bool LHSCondVal;
4703   if (CGF.ConstantFoldsToSimpleInteger(E->getLHS(), LHSCondVal)) {
4704     if (!LHSCondVal) { // If we have 0 || X, just emit X.
4705       CGF.incrementProfileCounter(E);
4706 
4707       // If the top of the logical operator nest, reset the MCDC temp to 0.
4708       if (CGF.MCDCLogOpStack.empty())
4709         CGF.maybeResetMCDCCondBitmap(E);
4710 
4711       CGF.MCDCLogOpStack.push_back(E);
4712 
4713       Value *RHSCond = CGF.EvaluateExprAsBool(E->getRHS());
4714 
4715       // If we're generating for profiling or coverage, generate a branch to a
4716       // block that increments the RHS counter need to track branch condition
4717       // coverage. In this case, use "FBlock" as both the final "TrueBlock" and
4718       // "FalseBlock" after the increment is done.
4719       if (InstrumentRegions &&
4720           CodeGenFunction::isInstrumentedCondition(E->getRHS())) {
4721         CGF.maybeUpdateMCDCCondBitmap(E->getRHS(), RHSCond);
4722         llvm::BasicBlock *FBlock = CGF.createBasicBlock("lor.end");
4723         llvm::BasicBlock *RHSBlockCnt = CGF.createBasicBlock("lor.rhscnt");
4724         Builder.CreateCondBr(RHSCond, FBlock, RHSBlockCnt);
4725         CGF.EmitBlock(RHSBlockCnt);
4726         CGF.incrementProfileCounter(E->getRHS());
4727         CGF.EmitBranch(FBlock);
4728         CGF.EmitBlock(FBlock);
4729       }
4730 
4731       CGF.MCDCLogOpStack.pop_back();
4732       // If the top of the logical operator nest, update the MCDC bitmap.
4733       if (CGF.MCDCLogOpStack.empty())
4734         CGF.maybeUpdateMCDCTestVectorBitmap(E);
4735 
4736       // ZExt result to int or bool.
4737       return Builder.CreateZExtOrBitCast(RHSCond, ResTy, "lor.ext");
4738     }
4739 
4740     // 1 || RHS: If it is safe, just elide the RHS, and return 1/true.
4741     if (!CGF.ContainsLabel(E->getRHS()))
4742       return llvm::ConstantInt::get(ResTy, 1);
4743   }
4744 
4745   // If the top of the logical operator nest, reset the MCDC temp to 0.
4746   if (CGF.MCDCLogOpStack.empty())
4747     CGF.maybeResetMCDCCondBitmap(E);
4748 
4749   CGF.MCDCLogOpStack.push_back(E);
4750 
4751   llvm::BasicBlock *ContBlock = CGF.createBasicBlock("lor.end");
4752   llvm::BasicBlock *RHSBlock = CGF.createBasicBlock("lor.rhs");
4753 
4754   CodeGenFunction::ConditionalEvaluation eval(CGF);
4755 
4756   // Branch on the LHS first.  If it is true, go to the success (cont) block.
4757   CGF.EmitBranchOnBoolExpr(E->getLHS(), ContBlock, RHSBlock,
4758                            CGF.getCurrentProfileCount() -
4759                                CGF.getProfileCount(E->getRHS()));
4760 
4761   // Any edges into the ContBlock are now from an (indeterminate number of)
4762   // edges from this first condition.  All of these values will be true.  Start
4763   // setting up the PHI node in the Cont Block for this.
4764   llvm::PHINode *PN = llvm::PHINode::Create(llvm::Type::getInt1Ty(VMContext), 2,
4765                                             "", ContBlock);
4766   for (llvm::pred_iterator PI = pred_begin(ContBlock), PE = pred_end(ContBlock);
4767        PI != PE; ++PI)
4768     PN->addIncoming(llvm::ConstantInt::getTrue(VMContext), *PI);
4769 
4770   eval.begin(CGF);
4771 
4772   // Emit the RHS condition as a bool value.
4773   CGF.EmitBlock(RHSBlock);
4774   CGF.incrementProfileCounter(E);
4775   Value *RHSCond = CGF.EvaluateExprAsBool(E->getRHS());
4776 
4777   eval.end(CGF);
4778 
4779   // Reaquire the RHS block, as there may be subblocks inserted.
4780   RHSBlock = Builder.GetInsertBlock();
4781 
4782   // If we're generating for profiling or coverage, generate a branch on the
4783   // RHS to a block that increments the RHS true counter needed to track branch
4784   // condition coverage.
4785   if (InstrumentRegions &&
4786       CodeGenFunction::isInstrumentedCondition(E->getRHS())) {
4787     CGF.maybeUpdateMCDCCondBitmap(E->getRHS(), RHSCond);
4788     llvm::BasicBlock *RHSBlockCnt = CGF.createBasicBlock("lor.rhscnt");
4789     Builder.CreateCondBr(RHSCond, ContBlock, RHSBlockCnt);
4790     CGF.EmitBlock(RHSBlockCnt);
4791     CGF.incrementProfileCounter(E->getRHS());
4792     CGF.EmitBranch(ContBlock);
4793     PN->addIncoming(RHSCond, RHSBlockCnt);
4794   }
4795 
4796   // Emit an unconditional branch from this block to ContBlock.  Insert an entry
4797   // into the phi node for the edge with the value of RHSCond.
4798   CGF.EmitBlock(ContBlock);
4799   PN->addIncoming(RHSCond, RHSBlock);
4800 
4801   CGF.MCDCLogOpStack.pop_back();
4802   // If the top of the logical operator nest, update the MCDC bitmap.
4803   if (CGF.MCDCLogOpStack.empty())
4804     CGF.maybeUpdateMCDCTestVectorBitmap(E);
4805 
4806   // ZExt result to int.
4807   return Builder.CreateZExtOrBitCast(PN, ResTy, "lor.ext");
4808 }
4809 
4810 Value *ScalarExprEmitter::VisitBinComma(const BinaryOperator *E) {
4811   CGF.EmitIgnoredExpr(E->getLHS());
4812   CGF.EnsureInsertPoint();
4813   return Visit(E->getRHS());
4814 }
4815 
4816 //===----------------------------------------------------------------------===//
4817 //                             Other Operators
4818 //===----------------------------------------------------------------------===//
4819 
4820 /// isCheapEnoughToEvaluateUnconditionally - Return true if the specified
4821 /// expression is cheap enough and side-effect-free enough to evaluate
4822 /// unconditionally instead of conditionally.  This is used to convert control
4823 /// flow into selects in some cases.
4824 static bool isCheapEnoughToEvaluateUnconditionally(const Expr *E,
4825                                                    CodeGenFunction &CGF) {
4826   // Anything that is an integer or floating point constant is fine.
4827   return E->IgnoreParens()->isEvaluatable(CGF.getContext());
4828 
4829   // Even non-volatile automatic variables can't be evaluated unconditionally.
4830   // Referencing a thread_local may cause non-trivial initialization work to
4831   // occur. If we're inside a lambda and one of the variables is from the scope
4832   // outside the lambda, that function may have returned already. Reading its
4833   // locals is a bad idea. Also, these reads may introduce races there didn't
4834   // exist in the source-level program.
4835 }
4836 
4837 
4838 Value *ScalarExprEmitter::
4839 VisitAbstractConditionalOperator(const AbstractConditionalOperator *E) {
4840   TestAndClearIgnoreResultAssign();
4841 
4842   // Bind the common expression if necessary.
4843   CodeGenFunction::OpaqueValueMapping binding(CGF, E);
4844 
4845   Expr *condExpr = E->getCond();
4846   Expr *lhsExpr = E->getTrueExpr();
4847   Expr *rhsExpr = E->getFalseExpr();
4848 
4849   // If the condition constant folds and can be elided, try to avoid emitting
4850   // the condition and the dead arm.
4851   bool CondExprBool;
4852   if (CGF.ConstantFoldsToSimpleInteger(condExpr, CondExprBool)) {
4853     Expr *live = lhsExpr, *dead = rhsExpr;
4854     if (!CondExprBool) std::swap(live, dead);
4855 
4856     // If the dead side doesn't have labels we need, just emit the Live part.
4857     if (!CGF.ContainsLabel(dead)) {
4858       if (CondExprBool)
4859         CGF.incrementProfileCounter(E);
4860       Value *Result = Visit(live);
4861 
4862       // If the live part is a throw expression, it acts like it has a void
4863       // type, so evaluating it returns a null Value*.  However, a conditional
4864       // with non-void type must return a non-null Value*.
4865       if (!Result && !E->getType()->isVoidType())
4866         Result = llvm::UndefValue::get(CGF.ConvertType(E->getType()));
4867 
4868       return Result;
4869     }
4870   }
4871 
4872   // OpenCL: If the condition is a vector, we can treat this condition like
4873   // the select function.
4874   if ((CGF.getLangOpts().OpenCL && condExpr->getType()->isVectorType()) ||
4875       condExpr->getType()->isExtVectorType()) {
4876     CGF.incrementProfileCounter(E);
4877 
4878     llvm::Value *CondV = CGF.EmitScalarExpr(condExpr);
4879     llvm::Value *LHS = Visit(lhsExpr);
4880     llvm::Value *RHS = Visit(rhsExpr);
4881 
4882     llvm::Type *condType = ConvertType(condExpr->getType());
4883     auto *vecTy = cast<llvm::FixedVectorType>(condType);
4884 
4885     unsigned numElem = vecTy->getNumElements();
4886     llvm::Type *elemType = vecTy->getElementType();
4887 
4888     llvm::Value *zeroVec = llvm::Constant::getNullValue(vecTy);
4889     llvm::Value *TestMSB = Builder.CreateICmpSLT(CondV, zeroVec);
4890     llvm::Value *tmp = Builder.CreateSExt(
4891         TestMSB, llvm::FixedVectorType::get(elemType, numElem), "sext");
4892     llvm::Value *tmp2 = Builder.CreateNot(tmp);
4893 
4894     // Cast float to int to perform ANDs if necessary.
4895     llvm::Value *RHSTmp = RHS;
4896     llvm::Value *LHSTmp = LHS;
4897     bool wasCast = false;
4898     llvm::VectorType *rhsVTy = cast<llvm::VectorType>(RHS->getType());
4899     if (rhsVTy->getElementType()->isFloatingPointTy()) {
4900       RHSTmp = Builder.CreateBitCast(RHS, tmp2->getType());
4901       LHSTmp = Builder.CreateBitCast(LHS, tmp->getType());
4902       wasCast = true;
4903     }
4904 
4905     llvm::Value *tmp3 = Builder.CreateAnd(RHSTmp, tmp2);
4906     llvm::Value *tmp4 = Builder.CreateAnd(LHSTmp, tmp);
4907     llvm::Value *tmp5 = Builder.CreateOr(tmp3, tmp4, "cond");
4908     if (wasCast)
4909       tmp5 = Builder.CreateBitCast(tmp5, RHS->getType());
4910 
4911     return tmp5;
4912   }
4913 
4914   if (condExpr->getType()->isVectorType() ||
4915       condExpr->getType()->isSveVLSBuiltinType()) {
4916     CGF.incrementProfileCounter(E);
4917 
4918     llvm::Value *CondV = CGF.EmitScalarExpr(condExpr);
4919     llvm::Value *LHS = Visit(lhsExpr);
4920     llvm::Value *RHS = Visit(rhsExpr);
4921 
4922     llvm::Type *CondType = ConvertType(condExpr->getType());
4923     auto *VecTy = cast<llvm::VectorType>(CondType);
4924     llvm::Value *ZeroVec = llvm::Constant::getNullValue(VecTy);
4925 
4926     CondV = Builder.CreateICmpNE(CondV, ZeroVec, "vector_cond");
4927     return Builder.CreateSelect(CondV, LHS, RHS, "vector_select");
4928   }
4929 
4930   // If this is a really simple expression (like x ? 4 : 5), emit this as a
4931   // select instead of as control flow.  We can only do this if it is cheap and
4932   // safe to evaluate the LHS and RHS unconditionally.
4933   if (isCheapEnoughToEvaluateUnconditionally(lhsExpr, CGF) &&
4934       isCheapEnoughToEvaluateUnconditionally(rhsExpr, CGF)) {
4935     llvm::Value *CondV = CGF.EvaluateExprAsBool(condExpr);
4936     llvm::Value *StepV = Builder.CreateZExtOrBitCast(CondV, CGF.Int64Ty);
4937 
4938     CGF.incrementProfileCounter(E, StepV);
4939 
4940     llvm::Value *LHS = Visit(lhsExpr);
4941     llvm::Value *RHS = Visit(rhsExpr);
4942     if (!LHS) {
4943       // If the conditional has void type, make sure we return a null Value*.
4944       assert(!RHS && "LHS and RHS types must match");
4945       return nullptr;
4946     }
4947     return Builder.CreateSelect(CondV, LHS, RHS, "cond");
4948   }
4949 
4950   // If the top of the logical operator nest, reset the MCDC temp to 0.
4951   if (CGF.MCDCLogOpStack.empty())
4952     CGF.maybeResetMCDCCondBitmap(condExpr);
4953 
4954   llvm::BasicBlock *LHSBlock = CGF.createBasicBlock("cond.true");
4955   llvm::BasicBlock *RHSBlock = CGF.createBasicBlock("cond.false");
4956   llvm::BasicBlock *ContBlock = CGF.createBasicBlock("cond.end");
4957 
4958   CodeGenFunction::ConditionalEvaluation eval(CGF);
4959   CGF.EmitBranchOnBoolExpr(condExpr, LHSBlock, RHSBlock,
4960                            CGF.getProfileCount(lhsExpr));
4961 
4962   CGF.EmitBlock(LHSBlock);
4963 
4964   // If the top of the logical operator nest, update the MCDC bitmap for the
4965   // ConditionalOperator prior to visiting its LHS and RHS blocks, since they
4966   // may also contain a boolean expression.
4967   if (CGF.MCDCLogOpStack.empty())
4968     CGF.maybeUpdateMCDCTestVectorBitmap(condExpr);
4969 
4970   CGF.incrementProfileCounter(E);
4971   eval.begin(CGF);
4972   Value *LHS = Visit(lhsExpr);
4973   eval.end(CGF);
4974 
4975   LHSBlock = Builder.GetInsertBlock();
4976   Builder.CreateBr(ContBlock);
4977 
4978   CGF.EmitBlock(RHSBlock);
4979 
4980   // If the top of the logical operator nest, update the MCDC bitmap for the
4981   // ConditionalOperator prior to visiting its LHS and RHS blocks, since they
4982   // may also contain a boolean expression.
4983   if (CGF.MCDCLogOpStack.empty())
4984     CGF.maybeUpdateMCDCTestVectorBitmap(condExpr);
4985 
4986   eval.begin(CGF);
4987   Value *RHS = Visit(rhsExpr);
4988   eval.end(CGF);
4989 
4990   RHSBlock = Builder.GetInsertBlock();
4991   CGF.EmitBlock(ContBlock);
4992 
4993   // If the LHS or RHS is a throw expression, it will be legitimately null.
4994   if (!LHS)
4995     return RHS;
4996   if (!RHS)
4997     return LHS;
4998 
4999   // Create a PHI node for the real part.
5000   llvm::PHINode *PN = Builder.CreatePHI(LHS->getType(), 2, "cond");
5001   PN->addIncoming(LHS, LHSBlock);
5002   PN->addIncoming(RHS, RHSBlock);
5003 
5004   return PN;
5005 }
5006 
5007 Value *ScalarExprEmitter::VisitChooseExpr(ChooseExpr *E) {
5008   return Visit(E->getChosenSubExpr());
5009 }
5010 
5011 Value *ScalarExprEmitter::VisitVAArgExpr(VAArgExpr *VE) {
5012   QualType Ty = VE->getType();
5013 
5014   if (Ty->isVariablyModifiedType())
5015     CGF.EmitVariablyModifiedType(Ty);
5016 
5017   Address ArgValue = Address::invalid();
5018   Address ArgPtr = CGF.EmitVAArg(VE, ArgValue);
5019 
5020   llvm::Type *ArgTy = ConvertType(VE->getType());
5021 
5022   // If EmitVAArg fails, emit an error.
5023   if (!ArgPtr.isValid()) {
5024     CGF.ErrorUnsupported(VE, "va_arg expression");
5025     return llvm::UndefValue::get(ArgTy);
5026   }
5027 
5028   // FIXME Volatility.
5029   llvm::Value *Val = Builder.CreateLoad(ArgPtr);
5030 
5031   // If EmitVAArg promoted the type, we must truncate it.
5032   if (ArgTy != Val->getType()) {
5033     if (ArgTy->isPointerTy() && !Val->getType()->isPointerTy())
5034       Val = Builder.CreateIntToPtr(Val, ArgTy);
5035     else
5036       Val = Builder.CreateTrunc(Val, ArgTy);
5037   }
5038 
5039   return Val;
5040 }
5041 
5042 Value *ScalarExprEmitter::VisitBlockExpr(const BlockExpr *block) {
5043   return CGF.EmitBlockLiteral(block);
5044 }
5045 
5046 // Convert a vec3 to vec4, or vice versa.
5047 static Value *ConvertVec3AndVec4(CGBuilderTy &Builder, CodeGenFunction &CGF,
5048                                  Value *Src, unsigned NumElementsDst) {
5049   static constexpr int Mask[] = {0, 1, 2, -1};
5050   return Builder.CreateShuffleVector(Src, llvm::ArrayRef(Mask, NumElementsDst));
5051 }
5052 
5053 // Create cast instructions for converting LLVM value \p Src to LLVM type \p
5054 // DstTy. \p Src has the same size as \p DstTy. Both are single value types
5055 // but could be scalar or vectors of different lengths, and either can be
5056 // pointer.
5057 // There are 4 cases:
5058 // 1. non-pointer -> non-pointer  : needs 1 bitcast
5059 // 2. pointer -> pointer          : needs 1 bitcast or addrspacecast
5060 // 3. pointer -> non-pointer
5061 //   a) pointer -> intptr_t       : needs 1 ptrtoint
5062 //   b) pointer -> non-intptr_t   : needs 1 ptrtoint then 1 bitcast
5063 // 4. non-pointer -> pointer
5064 //   a) intptr_t -> pointer       : needs 1 inttoptr
5065 //   b) non-intptr_t -> pointer   : needs 1 bitcast then 1 inttoptr
5066 // Note: for cases 3b and 4b two casts are required since LLVM casts do not
5067 // allow casting directly between pointer types and non-integer non-pointer
5068 // types.
5069 static Value *createCastsForTypeOfSameSize(CGBuilderTy &Builder,
5070                                            const llvm::DataLayout &DL,
5071                                            Value *Src, llvm::Type *DstTy,
5072                                            StringRef Name = "") {
5073   auto SrcTy = Src->getType();
5074 
5075   // Case 1.
5076   if (!SrcTy->isPointerTy() && !DstTy->isPointerTy())
5077     return Builder.CreateBitCast(Src, DstTy, Name);
5078 
5079   // Case 2.
5080   if (SrcTy->isPointerTy() && DstTy->isPointerTy())
5081     return Builder.CreatePointerBitCastOrAddrSpaceCast(Src, DstTy, Name);
5082 
5083   // Case 3.
5084   if (SrcTy->isPointerTy() && !DstTy->isPointerTy()) {
5085     // Case 3b.
5086     if (!DstTy->isIntegerTy())
5087       Src = Builder.CreatePtrToInt(Src, DL.getIntPtrType(SrcTy));
5088     // Cases 3a and 3b.
5089     return Builder.CreateBitOrPointerCast(Src, DstTy, Name);
5090   }
5091 
5092   // Case 4b.
5093   if (!SrcTy->isIntegerTy())
5094     Src = Builder.CreateBitCast(Src, DL.getIntPtrType(DstTy));
5095   // Cases 4a and 4b.
5096   return Builder.CreateIntToPtr(Src, DstTy, Name);
5097 }
5098 
5099 Value *ScalarExprEmitter::VisitAsTypeExpr(AsTypeExpr *E) {
5100   Value *Src  = CGF.EmitScalarExpr(E->getSrcExpr());
5101   llvm::Type *DstTy = ConvertType(E->getType());
5102 
5103   llvm::Type *SrcTy = Src->getType();
5104   unsigned NumElementsSrc =
5105       isa<llvm::VectorType>(SrcTy)
5106           ? cast<llvm::FixedVectorType>(SrcTy)->getNumElements()
5107           : 0;
5108   unsigned NumElementsDst =
5109       isa<llvm::VectorType>(DstTy)
5110           ? cast<llvm::FixedVectorType>(DstTy)->getNumElements()
5111           : 0;
5112 
5113   // Use bit vector expansion for ext_vector_type boolean vectors.
5114   if (E->getType()->isExtVectorBoolType())
5115     return CGF.emitBoolVecConversion(Src, NumElementsDst, "astype");
5116 
5117   // Going from vec3 to non-vec3 is a special case and requires a shuffle
5118   // vector to get a vec4, then a bitcast if the target type is different.
5119   if (NumElementsSrc == 3 && NumElementsDst != 3) {
5120     Src = ConvertVec3AndVec4(Builder, CGF, Src, 4);
5121     Src = createCastsForTypeOfSameSize(Builder, CGF.CGM.getDataLayout(), Src,
5122                                        DstTy);
5123 
5124     Src->setName("astype");
5125     return Src;
5126   }
5127 
5128   // Going from non-vec3 to vec3 is a special case and requires a bitcast
5129   // to vec4 if the original type is not vec4, then a shuffle vector to
5130   // get a vec3.
5131   if (NumElementsSrc != 3 && NumElementsDst == 3) {
5132     auto *Vec4Ty = llvm::FixedVectorType::get(
5133         cast<llvm::VectorType>(DstTy)->getElementType(), 4);
5134     Src = createCastsForTypeOfSameSize(Builder, CGF.CGM.getDataLayout(), Src,
5135                                        Vec4Ty);
5136 
5137     Src = ConvertVec3AndVec4(Builder, CGF, Src, 3);
5138     Src->setName("astype");
5139     return Src;
5140   }
5141 
5142   return createCastsForTypeOfSameSize(Builder, CGF.CGM.getDataLayout(),
5143                                       Src, DstTy, "astype");
5144 }
5145 
5146 Value *ScalarExprEmitter::VisitAtomicExpr(AtomicExpr *E) {
5147   return CGF.EmitAtomicExpr(E).getScalarVal();
5148 }
5149 
5150 //===----------------------------------------------------------------------===//
5151 //                         Entry Point into this File
5152 //===----------------------------------------------------------------------===//
5153 
5154 /// Emit the computation of the specified expression of scalar type, ignoring
5155 /// the result.
5156 Value *CodeGenFunction::EmitScalarExpr(const Expr *E, bool IgnoreResultAssign) {
5157   assert(E && hasScalarEvaluationKind(E->getType()) &&
5158          "Invalid scalar expression to emit");
5159 
5160   return ScalarExprEmitter(*this, IgnoreResultAssign)
5161       .Visit(const_cast<Expr *>(E));
5162 }
5163 
5164 /// Emit a conversion from the specified type to the specified destination type,
5165 /// both of which are LLVM scalar types.
5166 Value *CodeGenFunction::EmitScalarConversion(Value *Src, QualType SrcTy,
5167                                              QualType DstTy,
5168                                              SourceLocation Loc) {
5169   assert(hasScalarEvaluationKind(SrcTy) && hasScalarEvaluationKind(DstTy) &&
5170          "Invalid scalar expression to emit");
5171   return ScalarExprEmitter(*this).EmitScalarConversion(Src, SrcTy, DstTy, Loc);
5172 }
5173 
5174 /// Emit a conversion from the specified complex type to the specified
5175 /// destination type, where the destination type is an LLVM scalar type.
5176 Value *CodeGenFunction::EmitComplexToScalarConversion(ComplexPairTy Src,
5177                                                       QualType SrcTy,
5178                                                       QualType DstTy,
5179                                                       SourceLocation Loc) {
5180   assert(SrcTy->isAnyComplexType() && hasScalarEvaluationKind(DstTy) &&
5181          "Invalid complex -> scalar conversion");
5182   return ScalarExprEmitter(*this)
5183       .EmitComplexToScalarConversion(Src, SrcTy, DstTy, Loc);
5184 }
5185 
5186 
5187 Value *
5188 CodeGenFunction::EmitPromotedScalarExpr(const Expr *E,
5189                                         QualType PromotionType) {
5190   if (!PromotionType.isNull())
5191     return ScalarExprEmitter(*this).EmitPromoted(E, PromotionType);
5192   else
5193     return ScalarExprEmitter(*this).Visit(const_cast<Expr *>(E));
5194 }
5195 
5196 
5197 llvm::Value *CodeGenFunction::
5198 EmitScalarPrePostIncDec(const UnaryOperator *E, LValue LV,
5199                         bool isInc, bool isPre) {
5200   return ScalarExprEmitter(*this).EmitScalarPrePostIncDec(E, LV, isInc, isPre);
5201 }
5202 
5203 LValue CodeGenFunction::EmitObjCIsaExpr(const ObjCIsaExpr *E) {
5204   // object->isa or (*object).isa
5205   // Generate code as for: *(Class*)object
5206 
5207   Expr *BaseExpr = E->getBase();
5208   Address Addr = Address::invalid();
5209   if (BaseExpr->isPRValue()) {
5210     llvm::Type *BaseTy =
5211         ConvertTypeForMem(BaseExpr->getType()->getPointeeType());
5212     Addr = Address(EmitScalarExpr(BaseExpr), BaseTy, getPointerAlign());
5213   } else {
5214     Addr = EmitLValue(BaseExpr).getAddress(*this);
5215   }
5216 
5217   // Cast the address to Class*.
5218   Addr = Addr.withElementType(ConvertType(E->getType()));
5219   return MakeAddrLValue(Addr, E->getType());
5220 }
5221 
5222 
5223 LValue CodeGenFunction::EmitCompoundAssignmentLValue(
5224                                             const CompoundAssignOperator *E) {
5225   ScalarExprEmitter Scalar(*this);
5226   Value *Result = nullptr;
5227   switch (E->getOpcode()) {
5228 #define COMPOUND_OP(Op)                                                       \
5229     case BO_##Op##Assign:                                                     \
5230       return Scalar.EmitCompoundAssignLValue(E, &ScalarExprEmitter::Emit##Op, \
5231                                              Result)
5232   COMPOUND_OP(Mul);
5233   COMPOUND_OP(Div);
5234   COMPOUND_OP(Rem);
5235   COMPOUND_OP(Add);
5236   COMPOUND_OP(Sub);
5237   COMPOUND_OP(Shl);
5238   COMPOUND_OP(Shr);
5239   COMPOUND_OP(And);
5240   COMPOUND_OP(Xor);
5241   COMPOUND_OP(Or);
5242 #undef COMPOUND_OP
5243 
5244   case BO_PtrMemD:
5245   case BO_PtrMemI:
5246   case BO_Mul:
5247   case BO_Div:
5248   case BO_Rem:
5249   case BO_Add:
5250   case BO_Sub:
5251   case BO_Shl:
5252   case BO_Shr:
5253   case BO_LT:
5254   case BO_GT:
5255   case BO_LE:
5256   case BO_GE:
5257   case BO_EQ:
5258   case BO_NE:
5259   case BO_Cmp:
5260   case BO_And:
5261   case BO_Xor:
5262   case BO_Or:
5263   case BO_LAnd:
5264   case BO_LOr:
5265   case BO_Assign:
5266   case BO_Comma:
5267     llvm_unreachable("Not valid compound assignment operators");
5268   }
5269 
5270   llvm_unreachable("Unhandled compound assignment operator");
5271 }
5272 
5273 struct GEPOffsetAndOverflow {
5274   // The total (signed) byte offset for the GEP.
5275   llvm::Value *TotalOffset;
5276   // The offset overflow flag - true if the total offset overflows.
5277   llvm::Value *OffsetOverflows;
5278 };
5279 
5280 /// Evaluate given GEPVal, which is either an inbounds GEP, or a constant,
5281 /// and compute the total offset it applies from it's base pointer BasePtr.
5282 /// Returns offset in bytes and a boolean flag whether an overflow happened
5283 /// during evaluation.
5284 static GEPOffsetAndOverflow EmitGEPOffsetInBytes(Value *BasePtr, Value *GEPVal,
5285                                                  llvm::LLVMContext &VMContext,
5286                                                  CodeGenModule &CGM,
5287                                                  CGBuilderTy &Builder) {
5288   const auto &DL = CGM.getDataLayout();
5289 
5290   // The total (signed) byte offset for the GEP.
5291   llvm::Value *TotalOffset = nullptr;
5292 
5293   // Was the GEP already reduced to a constant?
5294   if (isa<llvm::Constant>(GEPVal)) {
5295     // Compute the offset by casting both pointers to integers and subtracting:
5296     // GEPVal = BasePtr + ptr(Offset) <--> Offset = int(GEPVal) - int(BasePtr)
5297     Value *BasePtr_int =
5298         Builder.CreatePtrToInt(BasePtr, DL.getIntPtrType(BasePtr->getType()));
5299     Value *GEPVal_int =
5300         Builder.CreatePtrToInt(GEPVal, DL.getIntPtrType(GEPVal->getType()));
5301     TotalOffset = Builder.CreateSub(GEPVal_int, BasePtr_int);
5302     return {TotalOffset, /*OffsetOverflows=*/Builder.getFalse()};
5303   }
5304 
5305   auto *GEP = cast<llvm::GEPOperator>(GEPVal);
5306   assert(GEP->getPointerOperand() == BasePtr &&
5307          "BasePtr must be the base of the GEP.");
5308   assert(GEP->isInBounds() && "Expected inbounds GEP");
5309 
5310   auto *IntPtrTy = DL.getIntPtrType(GEP->getPointerOperandType());
5311 
5312   // Grab references to the signed add/mul overflow intrinsics for intptr_t.
5313   auto *Zero = llvm::ConstantInt::getNullValue(IntPtrTy);
5314   auto *SAddIntrinsic =
5315       CGM.getIntrinsic(llvm::Intrinsic::sadd_with_overflow, IntPtrTy);
5316   auto *SMulIntrinsic =
5317       CGM.getIntrinsic(llvm::Intrinsic::smul_with_overflow, IntPtrTy);
5318 
5319   // The offset overflow flag - true if the total offset overflows.
5320   llvm::Value *OffsetOverflows = Builder.getFalse();
5321 
5322   /// Return the result of the given binary operation.
5323   auto eval = [&](BinaryOperator::Opcode Opcode, llvm::Value *LHS,
5324                   llvm::Value *RHS) -> llvm::Value * {
5325     assert((Opcode == BO_Add || Opcode == BO_Mul) && "Can't eval binop");
5326 
5327     // If the operands are constants, return a constant result.
5328     if (auto *LHSCI = dyn_cast<llvm::ConstantInt>(LHS)) {
5329       if (auto *RHSCI = dyn_cast<llvm::ConstantInt>(RHS)) {
5330         llvm::APInt N;
5331         bool HasOverflow = mayHaveIntegerOverflow(LHSCI, RHSCI, Opcode,
5332                                                   /*Signed=*/true, N);
5333         if (HasOverflow)
5334           OffsetOverflows = Builder.getTrue();
5335         return llvm::ConstantInt::get(VMContext, N);
5336       }
5337     }
5338 
5339     // Otherwise, compute the result with checked arithmetic.
5340     auto *ResultAndOverflow = Builder.CreateCall(
5341         (Opcode == BO_Add) ? SAddIntrinsic : SMulIntrinsic, {LHS, RHS});
5342     OffsetOverflows = Builder.CreateOr(
5343         Builder.CreateExtractValue(ResultAndOverflow, 1), OffsetOverflows);
5344     return Builder.CreateExtractValue(ResultAndOverflow, 0);
5345   };
5346 
5347   // Determine the total byte offset by looking at each GEP operand.
5348   for (auto GTI = llvm::gep_type_begin(GEP), GTE = llvm::gep_type_end(GEP);
5349        GTI != GTE; ++GTI) {
5350     llvm::Value *LocalOffset;
5351     auto *Index = GTI.getOperand();
5352     // Compute the local offset contributed by this indexing step:
5353     if (auto *STy = GTI.getStructTypeOrNull()) {
5354       // For struct indexing, the local offset is the byte position of the
5355       // specified field.
5356       unsigned FieldNo = cast<llvm::ConstantInt>(Index)->getZExtValue();
5357       LocalOffset = llvm::ConstantInt::get(
5358           IntPtrTy, DL.getStructLayout(STy)->getElementOffset(FieldNo));
5359     } else {
5360       // Otherwise this is array-like indexing. The local offset is the index
5361       // multiplied by the element size.
5362       auto *ElementSize =
5363           llvm::ConstantInt::get(IntPtrTy, GTI.getSequentialElementStride(DL));
5364       auto *IndexS = Builder.CreateIntCast(Index, IntPtrTy, /*isSigned=*/true);
5365       LocalOffset = eval(BO_Mul, ElementSize, IndexS);
5366     }
5367 
5368     // If this is the first offset, set it as the total offset. Otherwise, add
5369     // the local offset into the running total.
5370     if (!TotalOffset || TotalOffset == Zero)
5371       TotalOffset = LocalOffset;
5372     else
5373       TotalOffset = eval(BO_Add, TotalOffset, LocalOffset);
5374   }
5375 
5376   return {TotalOffset, OffsetOverflows};
5377 }
5378 
5379 Value *
5380 CodeGenFunction::EmitCheckedInBoundsGEP(llvm::Type *ElemTy, Value *Ptr,
5381                                         ArrayRef<Value *> IdxList,
5382                                         bool SignedIndices, bool IsSubtraction,
5383                                         SourceLocation Loc, const Twine &Name) {
5384   llvm::Type *PtrTy = Ptr->getType();
5385   Value *GEPVal = Builder.CreateInBoundsGEP(ElemTy, Ptr, IdxList, Name);
5386 
5387   // If the pointer overflow sanitizer isn't enabled, do nothing.
5388   if (!SanOpts.has(SanitizerKind::PointerOverflow))
5389     return GEPVal;
5390 
5391   // Perform nullptr-and-offset check unless the nullptr is defined.
5392   bool PerformNullCheck = !NullPointerIsDefined(
5393       Builder.GetInsertBlock()->getParent(), PtrTy->getPointerAddressSpace());
5394   // Check for overflows unless the GEP got constant-folded,
5395   // and only in the default address space
5396   bool PerformOverflowCheck =
5397       !isa<llvm::Constant>(GEPVal) && PtrTy->getPointerAddressSpace() == 0;
5398 
5399   if (!(PerformNullCheck || PerformOverflowCheck))
5400     return GEPVal;
5401 
5402   const auto &DL = CGM.getDataLayout();
5403 
5404   SanitizerScope SanScope(this);
5405   llvm::Type *IntPtrTy = DL.getIntPtrType(PtrTy);
5406 
5407   GEPOffsetAndOverflow EvaluatedGEP =
5408       EmitGEPOffsetInBytes(Ptr, GEPVal, getLLVMContext(), CGM, Builder);
5409 
5410   assert((!isa<llvm::Constant>(EvaluatedGEP.TotalOffset) ||
5411           EvaluatedGEP.OffsetOverflows == Builder.getFalse()) &&
5412          "If the offset got constant-folded, we don't expect that there was an "
5413          "overflow.");
5414 
5415   auto *Zero = llvm::ConstantInt::getNullValue(IntPtrTy);
5416 
5417   // Common case: if the total offset is zero, and we are using C++ semantics,
5418   // where nullptr+0 is defined, don't emit a check.
5419   if (EvaluatedGEP.TotalOffset == Zero && CGM.getLangOpts().CPlusPlus)
5420     return GEPVal;
5421 
5422   // Now that we've computed the total offset, add it to the base pointer (with
5423   // wrapping semantics).
5424   auto *IntPtr = Builder.CreatePtrToInt(Ptr, IntPtrTy);
5425   auto *ComputedGEP = Builder.CreateAdd(IntPtr, EvaluatedGEP.TotalOffset);
5426 
5427   llvm::SmallVector<std::pair<llvm::Value *, SanitizerMask>, 2> Checks;
5428 
5429   if (PerformNullCheck) {
5430     // In C++, if the base pointer evaluates to a null pointer value,
5431     // the only valid  pointer this inbounds GEP can produce is also
5432     // a null pointer, so the offset must also evaluate to zero.
5433     // Likewise, if we have non-zero base pointer, we can not get null pointer
5434     // as a result, so the offset can not be -intptr_t(BasePtr).
5435     // In other words, both pointers are either null, or both are non-null,
5436     // or the behaviour is undefined.
5437     //
5438     // C, however, is more strict in this regard, and gives more
5439     // optimization opportunities: in C, additionally, nullptr+0 is undefined.
5440     // So both the input to the 'gep inbounds' AND the output must not be null.
5441     auto *BaseIsNotNullptr = Builder.CreateIsNotNull(Ptr);
5442     auto *ResultIsNotNullptr = Builder.CreateIsNotNull(ComputedGEP);
5443     auto *Valid =
5444         CGM.getLangOpts().CPlusPlus
5445             ? Builder.CreateICmpEQ(BaseIsNotNullptr, ResultIsNotNullptr)
5446             : Builder.CreateAnd(BaseIsNotNullptr, ResultIsNotNullptr);
5447     Checks.emplace_back(Valid, SanitizerKind::PointerOverflow);
5448   }
5449 
5450   if (PerformOverflowCheck) {
5451     // The GEP is valid if:
5452     // 1) The total offset doesn't overflow, and
5453     // 2) The sign of the difference between the computed address and the base
5454     // pointer matches the sign of the total offset.
5455     llvm::Value *ValidGEP;
5456     auto *NoOffsetOverflow = Builder.CreateNot(EvaluatedGEP.OffsetOverflows);
5457     if (SignedIndices) {
5458       // GEP is computed as `unsigned base + signed offset`, therefore:
5459       // * If offset was positive, then the computed pointer can not be
5460       //   [unsigned] less than the base pointer, unless it overflowed.
5461       // * If offset was negative, then the computed pointer can not be
5462       //   [unsigned] greater than the bas pointere, unless it overflowed.
5463       auto *PosOrZeroValid = Builder.CreateICmpUGE(ComputedGEP, IntPtr);
5464       auto *PosOrZeroOffset =
5465           Builder.CreateICmpSGE(EvaluatedGEP.TotalOffset, Zero);
5466       llvm::Value *NegValid = Builder.CreateICmpULT(ComputedGEP, IntPtr);
5467       ValidGEP =
5468           Builder.CreateSelect(PosOrZeroOffset, PosOrZeroValid, NegValid);
5469     } else if (!IsSubtraction) {
5470       // GEP is computed as `unsigned base + unsigned offset`,  therefore the
5471       // computed pointer can not be [unsigned] less than base pointer,
5472       // unless there was an overflow.
5473       // Equivalent to `@llvm.uadd.with.overflow(%base, %offset)`.
5474       ValidGEP = Builder.CreateICmpUGE(ComputedGEP, IntPtr);
5475     } else {
5476       // GEP is computed as `unsigned base - unsigned offset`, therefore the
5477       // computed pointer can not be [unsigned] greater than base pointer,
5478       // unless there was an overflow.
5479       // Equivalent to `@llvm.usub.with.overflow(%base, sub(0, %offset))`.
5480       ValidGEP = Builder.CreateICmpULE(ComputedGEP, IntPtr);
5481     }
5482     ValidGEP = Builder.CreateAnd(ValidGEP, NoOffsetOverflow);
5483     Checks.emplace_back(ValidGEP, SanitizerKind::PointerOverflow);
5484   }
5485 
5486   assert(!Checks.empty() && "Should have produced some checks.");
5487 
5488   llvm::Constant *StaticArgs[] = {EmitCheckSourceLocation(Loc)};
5489   // Pass the computed GEP to the runtime to avoid emitting poisoned arguments.
5490   llvm::Value *DynamicArgs[] = {IntPtr, ComputedGEP};
5491   EmitCheck(Checks, SanitizerHandler::PointerOverflow, StaticArgs, DynamicArgs);
5492 
5493   return GEPVal;
5494 }
5495