xref: /freebsd/contrib/llvm-project/llvm/lib/Target/X86/X86InstrInfo.h (revision 77a1348b3c1cfe8547be49a121b56299a1e18b69)
1 //===-- X86InstrInfo.h - X86 Instruction Information ------------*- C++ -*-===//
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 file contains the X86 implementation of the TargetInstrInfo class.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #ifndef LLVM_LIB_TARGET_X86_X86INSTRINFO_H
14 #define LLVM_LIB_TARGET_X86_X86INSTRINFO_H
15 
16 #include "MCTargetDesc/X86BaseInfo.h"
17 #include "X86InstrFMA3Info.h"
18 #include "X86RegisterInfo.h"
19 #include "llvm/CodeGen/ISDOpcodes.h"
20 #include "llvm/CodeGen/TargetInstrInfo.h"
21 #include <vector>
22 
23 #define GET_INSTRINFO_HEADER
24 #include "X86GenInstrInfo.inc"
25 
26 namespace llvm {
27 class MachineInstrBuilder;
28 class X86RegisterInfo;
29 class X86Subtarget;
30 
31 namespace X86 {
32 
33 enum AsmComments {
34   // For instr that was compressed from EVEX to VEX.
35   AC_EVEX_2_VEX = MachineInstr::TAsmComments
36 };
37 
38 /// Return a pair of condition code for the given predicate and whether
39 /// the instruction operands should be swaped to match the condition code.
40 std::pair<CondCode, bool> getX86ConditionCode(CmpInst::Predicate Predicate);
41 
42 /// Return a setcc opcode based on whether it has a memory operand.
43 unsigned getSETOpc(bool HasMemoryOperand = false);
44 
45 /// Return a cmov opcode for the given register size in bytes, and operand type.
46 unsigned getCMovOpcode(unsigned RegBytes, bool HasMemoryOperand = false);
47 
48 // Turn jCC instruction into condition code.
49 CondCode getCondFromBranch(const MachineInstr &MI);
50 
51 // Turn setCC instruction into condition code.
52 CondCode getCondFromSETCC(const MachineInstr &MI);
53 
54 // Turn CMov instruction into condition code.
55 CondCode getCondFromCMov(const MachineInstr &MI);
56 
57 /// GetOppositeBranchCondition - Return the inverse of the specified cond,
58 /// e.g. turning COND_E to COND_NE.
59 CondCode GetOppositeBranchCondition(CondCode CC);
60 
61 /// Get the VPCMP immediate for the given condition.
62 unsigned getVPCMPImmForCond(ISD::CondCode CC);
63 
64 /// Get the VPCMP immediate if the opcodes are swapped.
65 unsigned getSwappedVPCMPImm(unsigned Imm);
66 
67 /// Get the VPCOM immediate if the opcodes are swapped.
68 unsigned getSwappedVPCOMImm(unsigned Imm);
69 
70 /// Get the VCMP immediate if the opcodes are swapped.
71 unsigned getSwappedVCMPImm(unsigned Imm);
72 
73 } // namespace X86
74 
75 /// isGlobalStubReference - Return true if the specified TargetFlag operand is
76 /// a reference to a stub for a global, not the global itself.
77 inline static bool isGlobalStubReference(unsigned char TargetFlag) {
78   switch (TargetFlag) {
79   case X86II::MO_DLLIMPORT:               // dllimport stub.
80   case X86II::MO_GOTPCREL:                // rip-relative GOT reference.
81   case X86II::MO_GOT:                     // normal GOT reference.
82   case X86II::MO_DARWIN_NONLAZY_PIC_BASE: // Normal $non_lazy_ptr ref.
83   case X86II::MO_DARWIN_NONLAZY:          // Normal $non_lazy_ptr ref.
84   case X86II::MO_COFFSTUB:                // COFF .refptr stub.
85     return true;
86   default:
87     return false;
88   }
89 }
90 
91 /// isGlobalRelativeToPICBase - Return true if the specified global value
92 /// reference is relative to a 32-bit PIC base (X86ISD::GlobalBaseReg).  If this
93 /// is true, the addressing mode has the PIC base register added in (e.g. EBX).
94 inline static bool isGlobalRelativeToPICBase(unsigned char TargetFlag) {
95   switch (TargetFlag) {
96   case X86II::MO_GOTOFF:                  // isPICStyleGOT: local global.
97   case X86II::MO_GOT:                     // isPICStyleGOT: other global.
98   case X86II::MO_PIC_BASE_OFFSET:         // Darwin local global.
99   case X86II::MO_DARWIN_NONLAZY_PIC_BASE: // Darwin/32 external global.
100   case X86II::MO_TLVP:                    // ??? Pretty sure..
101     return true;
102   default:
103     return false;
104   }
105 }
106 
107 inline static bool isScale(const MachineOperand &MO) {
108   return MO.isImm() && (MO.getImm() == 1 || MO.getImm() == 2 ||
109                         MO.getImm() == 4 || MO.getImm() == 8);
110 }
111 
112 inline static bool isLeaMem(const MachineInstr &MI, unsigned Op) {
113   if (MI.getOperand(Op).isFI())
114     return true;
115   return Op + X86::AddrSegmentReg <= MI.getNumOperands() &&
116          MI.getOperand(Op + X86::AddrBaseReg).isReg() &&
117          isScale(MI.getOperand(Op + X86::AddrScaleAmt)) &&
118          MI.getOperand(Op + X86::AddrIndexReg).isReg() &&
119          (MI.getOperand(Op + X86::AddrDisp).isImm() ||
120           MI.getOperand(Op + X86::AddrDisp).isGlobal() ||
121           MI.getOperand(Op + X86::AddrDisp).isCPI() ||
122           MI.getOperand(Op + X86::AddrDisp).isJTI());
123 }
124 
125 inline static bool isMem(const MachineInstr &MI, unsigned Op) {
126   if (MI.getOperand(Op).isFI())
127     return true;
128   return Op + X86::AddrNumOperands <= MI.getNumOperands() &&
129          MI.getOperand(Op + X86::AddrSegmentReg).isReg() && isLeaMem(MI, Op);
130 }
131 
132 class X86InstrInfo final : public X86GenInstrInfo {
133   X86Subtarget &Subtarget;
134   const X86RegisterInfo RI;
135 
136   virtual void anchor();
137 
138   bool AnalyzeBranchImpl(MachineBasicBlock &MBB, MachineBasicBlock *&TBB,
139                          MachineBasicBlock *&FBB,
140                          SmallVectorImpl<MachineOperand> &Cond,
141                          SmallVectorImpl<MachineInstr *> &CondBranches,
142                          bool AllowModify) const;
143 
144 public:
145   explicit X86InstrInfo(X86Subtarget &STI);
146 
147   /// getRegisterInfo - TargetInstrInfo is a superset of MRegister info.  As
148   /// such, whenever a client has an instance of instruction info, it should
149   /// always be able to get register info as well (through this method).
150   ///
151   const X86RegisterInfo &getRegisterInfo() const { return RI; }
152 
153   /// Returns the stack pointer adjustment that happens inside the frame
154   /// setup..destroy sequence (e.g. by pushes, or inside the callee).
155   int64_t getFrameAdjustment(const MachineInstr &I) const {
156     assert(isFrameInstr(I));
157     if (isFrameSetup(I))
158       return I.getOperand(2).getImm();
159     return I.getOperand(1).getImm();
160   }
161 
162   /// Sets the stack pointer adjustment made inside the frame made up by this
163   /// instruction.
164   void setFrameAdjustment(MachineInstr &I, int64_t V) const {
165     assert(isFrameInstr(I));
166     if (isFrameSetup(I))
167       I.getOperand(2).setImm(V);
168     else
169       I.getOperand(1).setImm(V);
170   }
171 
172   /// getSPAdjust - This returns the stack pointer adjustment made by
173   /// this instruction. For x86, we need to handle more complex call
174   /// sequences involving PUSHes.
175   int getSPAdjust(const MachineInstr &MI) const override;
176 
177   /// isCoalescableExtInstr - Return true if the instruction is a "coalescable"
178   /// extension instruction. That is, it's like a copy where it's legal for the
179   /// source to overlap the destination. e.g. X86::MOVSX64rr32. If this returns
180   /// true, then it's expected the pre-extension value is available as a subreg
181   /// of the result register. This also returns the sub-register index in
182   /// SubIdx.
183   bool isCoalescableExtInstr(const MachineInstr &MI, unsigned &SrcReg,
184                              unsigned &DstReg, unsigned &SubIdx) const override;
185 
186   unsigned isLoadFromStackSlot(const MachineInstr &MI,
187                                int &FrameIndex) const override;
188   unsigned isLoadFromStackSlot(const MachineInstr &MI,
189                                int &FrameIndex,
190                                unsigned &MemBytes) const override;
191   /// isLoadFromStackSlotPostFE - Check for post-frame ptr elimination
192   /// stack locations as well.  This uses a heuristic so it isn't
193   /// reliable for correctness.
194   unsigned isLoadFromStackSlotPostFE(const MachineInstr &MI,
195                                      int &FrameIndex) const override;
196 
197   unsigned isStoreToStackSlot(const MachineInstr &MI,
198                               int &FrameIndex) const override;
199   unsigned isStoreToStackSlot(const MachineInstr &MI,
200                               int &FrameIndex,
201                               unsigned &MemBytes) const override;
202   /// isStoreToStackSlotPostFE - Check for post-frame ptr elimination
203   /// stack locations as well.  This uses a heuristic so it isn't
204   /// reliable for correctness.
205   unsigned isStoreToStackSlotPostFE(const MachineInstr &MI,
206                                     int &FrameIndex) const override;
207 
208   bool isReallyTriviallyReMaterializable(const MachineInstr &MI,
209                                          AAResults *AA) const override;
210   void reMaterialize(MachineBasicBlock &MBB, MachineBasicBlock::iterator MI,
211                      unsigned DestReg, unsigned SubIdx,
212                      const MachineInstr &Orig,
213                      const TargetRegisterInfo &TRI) const override;
214 
215   /// Given an operand within a MachineInstr, insert preceding code to put it
216   /// into the right format for a particular kind of LEA instruction. This may
217   /// involve using an appropriate super-register instead (with an implicit use
218   /// of the original) or creating a new virtual register and inserting COPY
219   /// instructions to get the data into the right class.
220   ///
221   /// Reference parameters are set to indicate how caller should add this
222   /// operand to the LEA instruction.
223   bool classifyLEAReg(MachineInstr &MI, const MachineOperand &Src,
224                       unsigned LEAOpcode, bool AllowSP, Register &NewSrc,
225                       bool &isKill, MachineOperand &ImplicitOp,
226                       LiveVariables *LV) const;
227 
228   /// convertToThreeAddress - This method must be implemented by targets that
229   /// set the M_CONVERTIBLE_TO_3_ADDR flag.  When this flag is set, the target
230   /// may be able to convert a two-address instruction into a true
231   /// three-address instruction on demand.  This allows the X86 target (for
232   /// example) to convert ADD and SHL instructions into LEA instructions if they
233   /// would require register copies due to two-addressness.
234   ///
235   /// This method returns a null pointer if the transformation cannot be
236   /// performed, otherwise it returns the new instruction.
237   ///
238   MachineInstr *convertToThreeAddress(MachineFunction::iterator &MFI,
239                                       MachineInstr &MI,
240                                       LiveVariables *LV) const override;
241 
242   /// Returns true iff the routine could find two commutable operands in the
243   /// given machine instruction.
244   /// The 'SrcOpIdx1' and 'SrcOpIdx2' are INPUT and OUTPUT arguments. Their
245   /// input values can be re-defined in this method only if the input values
246   /// are not pre-defined, which is designated by the special value
247   /// 'CommuteAnyOperandIndex' assigned to it.
248   /// If both of indices are pre-defined and refer to some operands, then the
249   /// method simply returns true if the corresponding operands are commutable
250   /// and returns false otherwise.
251   ///
252   /// For example, calling this method this way:
253   ///     unsigned Op1 = 1, Op2 = CommuteAnyOperandIndex;
254   ///     findCommutedOpIndices(MI, Op1, Op2);
255   /// can be interpreted as a query asking to find an operand that would be
256   /// commutable with the operand#1.
257   bool findCommutedOpIndices(const MachineInstr &MI, unsigned &SrcOpIdx1,
258                              unsigned &SrcOpIdx2) const override;
259 
260   /// Returns an adjusted FMA opcode that must be used in FMA instruction that
261   /// performs the same computations as the given \p MI but which has the
262   /// operands \p SrcOpIdx1 and \p SrcOpIdx2 commuted.
263   /// It may return 0 if it is unsafe to commute the operands.
264   /// Note that a machine instruction (instead of its opcode) is passed as the
265   /// first parameter to make it possible to analyze the instruction's uses and
266   /// commute the first operand of FMA even when it seems unsafe when you look
267   /// at the opcode. For example, it is Ok to commute the first operand of
268   /// VFMADD*SD_Int, if ONLY the lowest 64-bit element of the result is used.
269   ///
270   /// The returned FMA opcode may differ from the opcode in the given \p MI.
271   /// For example, commuting the operands #1 and #3 in the following FMA
272   ///     FMA213 #1, #2, #3
273   /// results into instruction with adjusted opcode:
274   ///     FMA231 #3, #2, #1
275   unsigned
276   getFMA3OpcodeToCommuteOperands(const MachineInstr &MI, unsigned SrcOpIdx1,
277                                  unsigned SrcOpIdx2,
278                                  const X86InstrFMA3Group &FMA3Group) const;
279 
280   // Branch analysis.
281   bool isUnpredicatedTerminator(const MachineInstr &MI) const override;
282   bool isUnconditionalTailCall(const MachineInstr &MI) const override;
283   bool canMakeTailCallConditional(SmallVectorImpl<MachineOperand> &Cond,
284                                   const MachineInstr &TailCall) const override;
285   void replaceBranchWithTailCall(MachineBasicBlock &MBB,
286                                  SmallVectorImpl<MachineOperand> &Cond,
287                                  const MachineInstr &TailCall) const override;
288 
289   bool analyzeBranch(MachineBasicBlock &MBB, MachineBasicBlock *&TBB,
290                      MachineBasicBlock *&FBB,
291                      SmallVectorImpl<MachineOperand> &Cond,
292                      bool AllowModify) const override;
293 
294   bool getMemOperandWithOffset(const MachineInstr &LdSt,
295                                const MachineOperand *&BaseOp,
296                                int64_t &Offset,
297                                const TargetRegisterInfo *TRI) const override;
298   bool analyzeBranchPredicate(MachineBasicBlock &MBB,
299                               TargetInstrInfo::MachineBranchPredicate &MBP,
300                               bool AllowModify = false) const override;
301 
302   unsigned removeBranch(MachineBasicBlock &MBB,
303                         int *BytesRemoved = nullptr) const override;
304   unsigned insertBranch(MachineBasicBlock &MBB, MachineBasicBlock *TBB,
305                         MachineBasicBlock *FBB, ArrayRef<MachineOperand> Cond,
306                         const DebugLoc &DL,
307                         int *BytesAdded = nullptr) const override;
308   bool canInsertSelect(const MachineBasicBlock &, ArrayRef<MachineOperand> Cond,
309                        unsigned, unsigned, int &, int &, int &) const override;
310   void insertSelect(MachineBasicBlock &MBB, MachineBasicBlock::iterator MI,
311                     const DebugLoc &DL, unsigned DstReg,
312                     ArrayRef<MachineOperand> Cond, unsigned TrueReg,
313                     unsigned FalseReg) const override;
314   void copyPhysReg(MachineBasicBlock &MBB, MachineBasicBlock::iterator MI,
315                    const DebugLoc &DL, MCRegister DestReg, MCRegister SrcReg,
316                    bool KillSrc) const override;
317   void storeRegToStackSlot(MachineBasicBlock &MBB,
318                            MachineBasicBlock::iterator MI, unsigned SrcReg,
319                            bool isKill, int FrameIndex,
320                            const TargetRegisterClass *RC,
321                            const TargetRegisterInfo *TRI) const override;
322 
323   void loadRegFromStackSlot(MachineBasicBlock &MBB,
324                             MachineBasicBlock::iterator MI, unsigned DestReg,
325                             int FrameIndex, const TargetRegisterClass *RC,
326                             const TargetRegisterInfo *TRI) const override;
327 
328   bool expandPostRAPseudo(MachineInstr &MI) const override;
329 
330   /// Check whether the target can fold a load that feeds a subreg operand
331   /// (or a subreg operand that feeds a store).
332   bool isSubregFoldable() const override { return true; }
333 
334   /// foldMemoryOperand - If this target supports it, fold a load or store of
335   /// the specified stack slot into the specified machine instruction for the
336   /// specified operand(s).  If this is possible, the target should perform the
337   /// folding and return true, otherwise it should return false.  If it folds
338   /// the instruction, it is likely that the MachineInstruction the iterator
339   /// references has been changed.
340   MachineInstr *
341   foldMemoryOperandImpl(MachineFunction &MF, MachineInstr &MI,
342                         ArrayRef<unsigned> Ops,
343                         MachineBasicBlock::iterator InsertPt, int FrameIndex,
344                         LiveIntervals *LIS = nullptr,
345                         VirtRegMap *VRM = nullptr) const override;
346 
347   /// foldMemoryOperand - Same as the previous version except it allows folding
348   /// of any load and store from / to any address, not just from a specific
349   /// stack slot.
350   MachineInstr *foldMemoryOperandImpl(
351       MachineFunction &MF, MachineInstr &MI, ArrayRef<unsigned> Ops,
352       MachineBasicBlock::iterator InsertPt, MachineInstr &LoadMI,
353       LiveIntervals *LIS = nullptr) const override;
354 
355   /// unfoldMemoryOperand - Separate a single instruction which folded a load or
356   /// a store or a load and a store into two or more instruction. If this is
357   /// possible, returns true as well as the new instructions by reference.
358   bool
359   unfoldMemoryOperand(MachineFunction &MF, MachineInstr &MI, unsigned Reg,
360                       bool UnfoldLoad, bool UnfoldStore,
361                       SmallVectorImpl<MachineInstr *> &NewMIs) const override;
362 
363   bool unfoldMemoryOperand(SelectionDAG &DAG, SDNode *N,
364                            SmallVectorImpl<SDNode *> &NewNodes) const override;
365 
366   /// getOpcodeAfterMemoryUnfold - Returns the opcode of the would be new
367   /// instruction after load / store are unfolded from an instruction of the
368   /// specified opcode. It returns zero if the specified unfolding is not
369   /// possible. If LoadRegIndex is non-null, it is filled in with the operand
370   /// index of the operand which will hold the register holding the loaded
371   /// value.
372   unsigned
373   getOpcodeAfterMemoryUnfold(unsigned Opc, bool UnfoldLoad, bool UnfoldStore,
374                              unsigned *LoadRegIndex = nullptr) const override;
375 
376   /// areLoadsFromSameBasePtr - This is used by the pre-regalloc scheduler
377   /// to determine if two loads are loading from the same base address. It
378   /// should only return true if the base pointers are the same and the
379   /// only differences between the two addresses are the offset. It also returns
380   /// the offsets by reference.
381   bool areLoadsFromSameBasePtr(SDNode *Load1, SDNode *Load2, int64_t &Offset1,
382                                int64_t &Offset2) const override;
383 
384   /// shouldScheduleLoadsNear - This is a used by the pre-regalloc scheduler to
385   /// determine (in conjunction with areLoadsFromSameBasePtr) if two loads
386   /// should be scheduled togther. On some targets if two loads are loading from
387   /// addresses in the same cache line, it's better if they are scheduled
388   /// together. This function takes two integers that represent the load offsets
389   /// from the common base address. It returns true if it decides it's desirable
390   /// to schedule the two loads together. "NumLoads" is the number of loads that
391   /// have already been scheduled after Load1.
392   bool shouldScheduleLoadsNear(SDNode *Load1, SDNode *Load2, int64_t Offset1,
393                                int64_t Offset2,
394                                unsigned NumLoads) const override;
395 
396   void getNoop(MCInst &NopInst) const override;
397 
398   bool
399   reverseBranchCondition(SmallVectorImpl<MachineOperand> &Cond) const override;
400 
401   /// isSafeToMoveRegClassDefs - Return true if it's safe to move a machine
402   /// instruction that defines the specified register class.
403   bool isSafeToMoveRegClassDefs(const TargetRegisterClass *RC) const override;
404 
405   /// isSafeToClobberEFLAGS - Return true if it's safe insert an instruction tha
406   /// would clobber the EFLAGS condition register. Note the result may be
407   /// conservative. If it cannot definitely determine the safety after visiting
408   /// a few instructions in each direction it assumes it's not safe.
409   bool isSafeToClobberEFLAGS(MachineBasicBlock &MBB,
410                              MachineBasicBlock::iterator I) const {
411     return MBB.computeRegisterLiveness(&RI, X86::EFLAGS, I, 4) ==
412            MachineBasicBlock::LQR_Dead;
413   }
414 
415   /// True if MI has a condition code def, e.g. EFLAGS, that is
416   /// not marked dead.
417   bool hasLiveCondCodeDef(MachineInstr &MI) const;
418 
419   /// getGlobalBaseReg - Return a virtual register initialized with the
420   /// the global base register value. Output instructions required to
421   /// initialize the register in the function entry block, if necessary.
422   ///
423   unsigned getGlobalBaseReg(MachineFunction *MF) const;
424 
425   std::pair<uint16_t, uint16_t>
426   getExecutionDomain(const MachineInstr &MI) const override;
427 
428   uint16_t getExecutionDomainCustom(const MachineInstr &MI) const;
429 
430   void setExecutionDomain(MachineInstr &MI, unsigned Domain) const override;
431 
432   bool setExecutionDomainCustom(MachineInstr &MI, unsigned Domain) const;
433 
434   unsigned
435   getPartialRegUpdateClearance(const MachineInstr &MI, unsigned OpNum,
436                                const TargetRegisterInfo *TRI) const override;
437   unsigned getUndefRegClearance(const MachineInstr &MI, unsigned &OpNum,
438                                 const TargetRegisterInfo *TRI) const override;
439   void breakPartialRegDependency(MachineInstr &MI, unsigned OpNum,
440                                  const TargetRegisterInfo *TRI) const override;
441 
442   MachineInstr *foldMemoryOperandImpl(MachineFunction &MF, MachineInstr &MI,
443                                       unsigned OpNum,
444                                       ArrayRef<MachineOperand> MOs,
445                                       MachineBasicBlock::iterator InsertPt,
446                                       unsigned Size, unsigned Alignment,
447                                       bool AllowCommute) const;
448 
449   bool isHighLatencyDef(int opc) const override;
450 
451   bool hasHighOperandLatency(const TargetSchedModel &SchedModel,
452                              const MachineRegisterInfo *MRI,
453                              const MachineInstr &DefMI, unsigned DefIdx,
454                              const MachineInstr &UseMI,
455                              unsigned UseIdx) const override;
456 
457   bool useMachineCombiner() const override { return true; }
458 
459   bool isAssociativeAndCommutative(const MachineInstr &Inst) const override;
460 
461   bool hasReassociableOperands(const MachineInstr &Inst,
462                                const MachineBasicBlock *MBB) const override;
463 
464   void setSpecialOperandAttr(MachineInstr &OldMI1, MachineInstr &OldMI2,
465                              MachineInstr &NewMI1,
466                              MachineInstr &NewMI2) const override;
467 
468   /// analyzeCompare - For a comparison instruction, return the source registers
469   /// in SrcReg and SrcReg2 if having two register operands, and the value it
470   /// compares against in CmpValue. Return true if the comparison instruction
471   /// can be analyzed.
472   bool analyzeCompare(const MachineInstr &MI, unsigned &SrcReg,
473                       unsigned &SrcReg2, int &CmpMask,
474                       int &CmpValue) const override;
475 
476   /// optimizeCompareInstr - Check if there exists an earlier instruction that
477   /// operates on the same source operands and sets flags in the same way as
478   /// Compare; remove Compare if possible.
479   bool optimizeCompareInstr(MachineInstr &CmpInstr, unsigned SrcReg,
480                             unsigned SrcReg2, int CmpMask, int CmpValue,
481                             const MachineRegisterInfo *MRI) const override;
482 
483   /// optimizeLoadInstr - Try to remove the load by folding it to a register
484   /// operand at the use. We fold the load instructions if and only if the
485   /// def and use are in the same BB. We only look at one load and see
486   /// whether it can be folded into MI. FoldAsLoadDefReg is the virtual register
487   /// defined by the load we are trying to fold. DefMI returns the machine
488   /// instruction that defines FoldAsLoadDefReg, and the function returns
489   /// the machine instruction generated due to folding.
490   MachineInstr *optimizeLoadInstr(MachineInstr &MI,
491                                   const MachineRegisterInfo *MRI,
492                                   unsigned &FoldAsLoadDefReg,
493                                   MachineInstr *&DefMI) const override;
494 
495   std::pair<unsigned, unsigned>
496   decomposeMachineOperandsTargetFlags(unsigned TF) const override;
497 
498   ArrayRef<std::pair<unsigned, const char *>>
499   getSerializableDirectMachineOperandTargetFlags() const override;
500 
501   virtual outliner::OutlinedFunction getOutliningCandidateInfo(
502       std::vector<outliner::Candidate> &RepeatedSequenceLocs) const override;
503 
504   bool isFunctionSafeToOutlineFrom(MachineFunction &MF,
505                                    bool OutlineFromLinkOnceODRs) const override;
506 
507   outliner::InstrType
508   getOutliningType(MachineBasicBlock::iterator &MIT, unsigned Flags) const override;
509 
510   void buildOutlinedFrame(MachineBasicBlock &MBB, MachineFunction &MF,
511                           const outliner::OutlinedFunction &OF) const override;
512 
513   MachineBasicBlock::iterator
514   insertOutlinedCall(Module &M, MachineBasicBlock &MBB,
515                      MachineBasicBlock::iterator &It, MachineFunction &MF,
516                      const outliner::Candidate &C) const override;
517 
518 #define GET_INSTRINFO_HELPER_DECLS
519 #include "X86GenInstrInfo.inc"
520 
521   static bool hasLockPrefix(const MachineInstr &MI) {
522     return MI.getDesc().TSFlags & X86II::LOCK;
523   }
524 
525   Optional<ParamLoadedValue> describeLoadedValue(const MachineInstr &MI,
526                                                  Register Reg) const override;
527 
528 protected:
529   /// Commutes the operands in the given instruction by changing the operands
530   /// order and/or changing the instruction's opcode and/or the immediate value
531   /// operand.
532   ///
533   /// The arguments 'CommuteOpIdx1' and 'CommuteOpIdx2' specify the operands
534   /// to be commuted.
535   ///
536   /// Do not call this method for a non-commutable instruction or
537   /// non-commutable operands.
538   /// Even though the instruction is commutable, the method may still
539   /// fail to commute the operands, null pointer is returned in such cases.
540   MachineInstr *commuteInstructionImpl(MachineInstr &MI, bool NewMI,
541                                        unsigned CommuteOpIdx1,
542                                        unsigned CommuteOpIdx2) const override;
543 
544   /// If the specific machine instruction is a instruction that moves/copies
545   /// value from one register to another register return destination and source
546   /// registers as machine operands.
547   Optional<DestSourcePair>
548   isCopyInstrImpl(const MachineInstr &MI) const override;
549 
550 private:
551   /// This is a helper for convertToThreeAddress for 8 and 16-bit instructions.
552   /// We use 32-bit LEA to form 3-address code by promoting to a 32-bit
553   /// super-register and then truncating back down to a 8/16-bit sub-register.
554   MachineInstr *convertToThreeAddressWithLEA(unsigned MIOpc,
555                                              MachineFunction::iterator &MFI,
556                                              MachineInstr &MI,
557                                              LiveVariables *LV,
558                                              bool Is8BitOp) const;
559 
560   /// Handles memory folding for special case instructions, for instance those
561   /// requiring custom manipulation of the address.
562   MachineInstr *foldMemoryOperandCustom(MachineFunction &MF, MachineInstr &MI,
563                                         unsigned OpNum,
564                                         ArrayRef<MachineOperand> MOs,
565                                         MachineBasicBlock::iterator InsertPt,
566                                         unsigned Size, unsigned Align) const;
567 
568   /// isFrameOperand - Return true and the FrameIndex if the specified
569   /// operand and follow operands form a reference to the stack frame.
570   bool isFrameOperand(const MachineInstr &MI, unsigned int Op,
571                       int &FrameIndex) const;
572 
573   /// Returns true iff the routine could find two commutable operands in the
574   /// given machine instruction with 3 vector inputs.
575   /// The 'SrcOpIdx1' and 'SrcOpIdx2' are INPUT and OUTPUT arguments. Their
576   /// input values can be re-defined in this method only if the input values
577   /// are not pre-defined, which is designated by the special value
578   /// 'CommuteAnyOperandIndex' assigned to it.
579   /// If both of indices are pre-defined and refer to some operands, then the
580   /// method simply returns true if the corresponding operands are commutable
581   /// and returns false otherwise.
582   ///
583   /// For example, calling this method this way:
584   ///     unsigned Op1 = 1, Op2 = CommuteAnyOperandIndex;
585   ///     findThreeSrcCommutedOpIndices(MI, Op1, Op2);
586   /// can be interpreted as a query asking to find an operand that would be
587   /// commutable with the operand#1.
588   ///
589   /// If IsIntrinsic is set, operand 1 will be ignored for commuting.
590   bool findThreeSrcCommutedOpIndices(const MachineInstr &MI,
591                                      unsigned &SrcOpIdx1,
592                                      unsigned &SrcOpIdx2,
593                                      bool IsIntrinsic = false) const;
594 };
595 
596 } // namespace llvm
597 
598 #endif
599