xref: /freebsd/contrib/llvm-project/llvm/lib/Target/MSP430/MSP430ISelLowering.cpp (revision 1db9f3b21e39176dd5b67cf8ac378633b172463e)
1 //===-- MSP430ISelLowering.cpp - MSP430 DAG Lowering Implementation  ------===//
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 implements the MSP430TargetLowering class.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #include "MSP430ISelLowering.h"
14 #include "MSP430.h"
15 #include "MSP430MachineFunctionInfo.h"
16 #include "MSP430Subtarget.h"
17 #include "MSP430TargetMachine.h"
18 #include "llvm/CodeGen/CallingConvLower.h"
19 #include "llvm/CodeGen/MachineFrameInfo.h"
20 #include "llvm/CodeGen/MachineFunction.h"
21 #include "llvm/CodeGen/MachineInstrBuilder.h"
22 #include "llvm/CodeGen/MachineRegisterInfo.h"
23 #include "llvm/CodeGen/TargetLoweringObjectFileImpl.h"
24 #include "llvm/CodeGen/ValueTypes.h"
25 #include "llvm/IR/CallingConv.h"
26 #include "llvm/IR/DerivedTypes.h"
27 #include "llvm/IR/Function.h"
28 #include "llvm/IR/GlobalAlias.h"
29 #include "llvm/IR/GlobalVariable.h"
30 #include "llvm/IR/Intrinsics.h"
31 #include "llvm/Support/CommandLine.h"
32 #include "llvm/Support/Debug.h"
33 #include "llvm/Support/ErrorHandling.h"
34 #include "llvm/Support/raw_ostream.h"
35 using namespace llvm;
36 
37 #define DEBUG_TYPE "msp430-lower"
38 
39 static cl::opt<bool>MSP430NoLegalImmediate(
40   "msp430-no-legal-immediate", cl::Hidden,
41   cl::desc("Enable non legal immediates (for testing purposes only)"),
42   cl::init(false));
43 
44 MSP430TargetLowering::MSP430TargetLowering(const TargetMachine &TM,
45                                            const MSP430Subtarget &STI)
46     : TargetLowering(TM) {
47 
48   // Set up the register classes.
49   addRegisterClass(MVT::i8,  &MSP430::GR8RegClass);
50   addRegisterClass(MVT::i16, &MSP430::GR16RegClass);
51 
52   // Compute derived properties from the register classes
53   computeRegisterProperties(STI.getRegisterInfo());
54 
55   // Provide all sorts of operation actions
56   setStackPointerRegisterToSaveRestore(MSP430::SP);
57   setBooleanContents(ZeroOrOneBooleanContent);
58   setBooleanVectorContents(ZeroOrOneBooleanContent); // FIXME: Is this correct?
59 
60   // We have post-incremented loads / stores.
61   setIndexedLoadAction(ISD::POST_INC, MVT::i8, Legal);
62   setIndexedLoadAction(ISD::POST_INC, MVT::i16, Legal);
63 
64   for (MVT VT : MVT::integer_valuetypes()) {
65     setLoadExtAction(ISD::EXTLOAD,  VT, MVT::i1,  Promote);
66     setLoadExtAction(ISD::SEXTLOAD, VT, MVT::i1,  Promote);
67     setLoadExtAction(ISD::ZEXTLOAD, VT, MVT::i1,  Promote);
68     setLoadExtAction(ISD::SEXTLOAD, VT, MVT::i8,  Expand);
69     setLoadExtAction(ISD::SEXTLOAD, VT, MVT::i16, Expand);
70   }
71 
72   // We don't have any truncstores
73   setTruncStoreAction(MVT::i16, MVT::i8, Expand);
74 
75   setOperationAction(ISD::SRA,              MVT::i8,    Custom);
76   setOperationAction(ISD::SHL,              MVT::i8,    Custom);
77   setOperationAction(ISD::SRL,              MVT::i8,    Custom);
78   setOperationAction(ISD::SRA,              MVT::i16,   Custom);
79   setOperationAction(ISD::SHL,              MVT::i16,   Custom);
80   setOperationAction(ISD::SRL,              MVT::i16,   Custom);
81   setOperationAction(ISD::ROTL,             MVT::i8,    Expand);
82   setOperationAction(ISD::ROTR,             MVT::i8,    Expand);
83   setOperationAction(ISD::ROTL,             MVT::i16,   Expand);
84   setOperationAction(ISD::ROTR,             MVT::i16,   Expand);
85   setOperationAction(ISD::GlobalAddress,    MVT::i16,   Custom);
86   setOperationAction(ISD::ExternalSymbol,   MVT::i16,   Custom);
87   setOperationAction(ISD::BlockAddress,     MVT::i16,   Custom);
88   setOperationAction(ISD::BR_JT,            MVT::Other, Expand);
89   setOperationAction(ISD::BR_CC,            MVT::i8,    Custom);
90   setOperationAction(ISD::BR_CC,            MVT::i16,   Custom);
91   setOperationAction(ISD::BRCOND,           MVT::Other, Expand);
92   setOperationAction(ISD::SETCC,            MVT::i8,    Custom);
93   setOperationAction(ISD::SETCC,            MVT::i16,   Custom);
94   setOperationAction(ISD::SELECT,           MVT::i8,    Expand);
95   setOperationAction(ISD::SELECT,           MVT::i16,   Expand);
96   setOperationAction(ISD::SELECT_CC,        MVT::i8,    Custom);
97   setOperationAction(ISD::SELECT_CC,        MVT::i16,   Custom);
98   setOperationAction(ISD::SIGN_EXTEND,      MVT::i16,   Custom);
99   setOperationAction(ISD::DYNAMIC_STACKALLOC, MVT::i8, Expand);
100   setOperationAction(ISD::DYNAMIC_STACKALLOC, MVT::i16, Expand);
101   setOperationAction(ISD::STACKSAVE,        MVT::Other, Expand);
102   setOperationAction(ISD::STACKRESTORE,     MVT::Other, Expand);
103 
104   setOperationAction(ISD::CTTZ,             MVT::i8,    Expand);
105   setOperationAction(ISD::CTTZ,             MVT::i16,   Expand);
106   setOperationAction(ISD::CTLZ,             MVT::i8,    Expand);
107   setOperationAction(ISD::CTLZ,             MVT::i16,   Expand);
108   setOperationAction(ISD::CTPOP,            MVT::i8,    Expand);
109   setOperationAction(ISD::CTPOP,            MVT::i16,   Expand);
110 
111   setOperationAction(ISD::SHL_PARTS,        MVT::i8,    Expand);
112   setOperationAction(ISD::SHL_PARTS,        MVT::i16,   Expand);
113   setOperationAction(ISD::SRL_PARTS,        MVT::i8,    Expand);
114   setOperationAction(ISD::SRL_PARTS,        MVT::i16,   Expand);
115   setOperationAction(ISD::SRA_PARTS,        MVT::i8,    Expand);
116   setOperationAction(ISD::SRA_PARTS,        MVT::i16,   Expand);
117 
118   setOperationAction(ISD::SIGN_EXTEND_INREG, MVT::i1,   Expand);
119 
120   // FIXME: Implement efficiently multiplication by a constant
121   setOperationAction(ISD::MUL,              MVT::i8,    Promote);
122   setOperationAction(ISD::MULHS,            MVT::i8,    Promote);
123   setOperationAction(ISD::MULHU,            MVT::i8,    Promote);
124   setOperationAction(ISD::SMUL_LOHI,        MVT::i8,    Promote);
125   setOperationAction(ISD::UMUL_LOHI,        MVT::i8,    Promote);
126   setOperationAction(ISD::MUL,              MVT::i16,   LibCall);
127   setOperationAction(ISD::MULHS,            MVT::i16,   Expand);
128   setOperationAction(ISD::MULHU,            MVT::i16,   Expand);
129   setOperationAction(ISD::SMUL_LOHI,        MVT::i16,   Expand);
130   setOperationAction(ISD::UMUL_LOHI,        MVT::i16,   Expand);
131 
132   setOperationAction(ISD::UDIV,             MVT::i8,    Promote);
133   setOperationAction(ISD::UDIVREM,          MVT::i8,    Promote);
134   setOperationAction(ISD::UREM,             MVT::i8,    Promote);
135   setOperationAction(ISD::SDIV,             MVT::i8,    Promote);
136   setOperationAction(ISD::SDIVREM,          MVT::i8,    Promote);
137   setOperationAction(ISD::SREM,             MVT::i8,    Promote);
138   setOperationAction(ISD::UDIV,             MVT::i16,   LibCall);
139   setOperationAction(ISD::UDIVREM,          MVT::i16,   Expand);
140   setOperationAction(ISD::UREM,             MVT::i16,   LibCall);
141   setOperationAction(ISD::SDIV,             MVT::i16,   LibCall);
142   setOperationAction(ISD::SDIVREM,          MVT::i16,   Expand);
143   setOperationAction(ISD::SREM,             MVT::i16,   LibCall);
144 
145   // varargs support
146   setOperationAction(ISD::VASTART,          MVT::Other, Custom);
147   setOperationAction(ISD::VAARG,            MVT::Other, Expand);
148   setOperationAction(ISD::VAEND,            MVT::Other, Expand);
149   setOperationAction(ISD::VACOPY,           MVT::Other, Expand);
150   setOperationAction(ISD::JumpTable,        MVT::i16,   Custom);
151 
152   // EABI Libcalls - EABI Section 6.2
153   const struct {
154     const RTLIB::Libcall Op;
155     const char * const Name;
156     const ISD::CondCode Cond;
157   } LibraryCalls[] = {
158     // Floating point conversions - EABI Table 6
159     { RTLIB::FPROUND_F64_F32,   "__mspabi_cvtdf",   ISD::SETCC_INVALID },
160     { RTLIB::FPEXT_F32_F64,     "__mspabi_cvtfd",   ISD::SETCC_INVALID },
161     // The following is NOT implemented in libgcc
162     //{ RTLIB::FPTOSINT_F64_I16,  "__mspabi_fixdi", ISD::SETCC_INVALID },
163     { RTLIB::FPTOSINT_F64_I32,  "__mspabi_fixdli",  ISD::SETCC_INVALID },
164     { RTLIB::FPTOSINT_F64_I64,  "__mspabi_fixdlli", ISD::SETCC_INVALID },
165     // The following is NOT implemented in libgcc
166     //{ RTLIB::FPTOUINT_F64_I16,  "__mspabi_fixdu", ISD::SETCC_INVALID },
167     { RTLIB::FPTOUINT_F64_I32,  "__mspabi_fixdul",  ISD::SETCC_INVALID },
168     { RTLIB::FPTOUINT_F64_I64,  "__mspabi_fixdull", ISD::SETCC_INVALID },
169     // The following is NOT implemented in libgcc
170     //{ RTLIB::FPTOSINT_F32_I16,  "__mspabi_fixfi", ISD::SETCC_INVALID },
171     { RTLIB::FPTOSINT_F32_I32,  "__mspabi_fixfli",  ISD::SETCC_INVALID },
172     { RTLIB::FPTOSINT_F32_I64,  "__mspabi_fixflli", ISD::SETCC_INVALID },
173     // The following is NOT implemented in libgcc
174     //{ RTLIB::FPTOUINT_F32_I16,  "__mspabi_fixfu", ISD::SETCC_INVALID },
175     { RTLIB::FPTOUINT_F32_I32,  "__mspabi_fixful",  ISD::SETCC_INVALID },
176     { RTLIB::FPTOUINT_F32_I64,  "__mspabi_fixfull", ISD::SETCC_INVALID },
177     // TODO The following IS implemented in libgcc
178     //{ RTLIB::SINTTOFP_I16_F64,  "__mspabi_fltid", ISD::SETCC_INVALID },
179     { RTLIB::SINTTOFP_I32_F64,  "__mspabi_fltlid",  ISD::SETCC_INVALID },
180     // TODO The following IS implemented in libgcc but is not in the EABI
181     { RTLIB::SINTTOFP_I64_F64,  "__mspabi_fltllid", ISD::SETCC_INVALID },
182     // TODO The following IS implemented in libgcc
183     //{ RTLIB::UINTTOFP_I16_F64,  "__mspabi_fltud", ISD::SETCC_INVALID },
184     { RTLIB::UINTTOFP_I32_F64,  "__mspabi_fltuld",  ISD::SETCC_INVALID },
185     // The following IS implemented in libgcc but is not in the EABI
186     { RTLIB::UINTTOFP_I64_F64,  "__mspabi_fltulld", ISD::SETCC_INVALID },
187     // TODO The following IS implemented in libgcc
188     //{ RTLIB::SINTTOFP_I16_F32,  "__mspabi_fltif", ISD::SETCC_INVALID },
189     { RTLIB::SINTTOFP_I32_F32,  "__mspabi_fltlif",  ISD::SETCC_INVALID },
190     // TODO The following IS implemented in libgcc but is not in the EABI
191     { RTLIB::SINTTOFP_I64_F32,  "__mspabi_fltllif", ISD::SETCC_INVALID },
192     // TODO The following IS implemented in libgcc
193     //{ RTLIB::UINTTOFP_I16_F32,  "__mspabi_fltuf", ISD::SETCC_INVALID },
194     { RTLIB::UINTTOFP_I32_F32,  "__mspabi_fltulf",  ISD::SETCC_INVALID },
195     // The following IS implemented in libgcc but is not in the EABI
196     { RTLIB::UINTTOFP_I64_F32,  "__mspabi_fltullf", ISD::SETCC_INVALID },
197 
198     // Floating point comparisons - EABI Table 7
199     { RTLIB::OEQ_F64, "__mspabi_cmpd", ISD::SETEQ },
200     { RTLIB::UNE_F64, "__mspabi_cmpd", ISD::SETNE },
201     { RTLIB::OGE_F64, "__mspabi_cmpd", ISD::SETGE },
202     { RTLIB::OLT_F64, "__mspabi_cmpd", ISD::SETLT },
203     { RTLIB::OLE_F64, "__mspabi_cmpd", ISD::SETLE },
204     { RTLIB::OGT_F64, "__mspabi_cmpd", ISD::SETGT },
205     { RTLIB::OEQ_F32, "__mspabi_cmpf", ISD::SETEQ },
206     { RTLIB::UNE_F32, "__mspabi_cmpf", ISD::SETNE },
207     { RTLIB::OGE_F32, "__mspabi_cmpf", ISD::SETGE },
208     { RTLIB::OLT_F32, "__mspabi_cmpf", ISD::SETLT },
209     { RTLIB::OLE_F32, "__mspabi_cmpf", ISD::SETLE },
210     { RTLIB::OGT_F32, "__mspabi_cmpf", ISD::SETGT },
211 
212     // Floating point arithmetic - EABI Table 8
213     { RTLIB::ADD_F64,  "__mspabi_addd", ISD::SETCC_INVALID },
214     { RTLIB::ADD_F32,  "__mspabi_addf", ISD::SETCC_INVALID },
215     { RTLIB::DIV_F64,  "__mspabi_divd", ISD::SETCC_INVALID },
216     { RTLIB::DIV_F32,  "__mspabi_divf", ISD::SETCC_INVALID },
217     { RTLIB::MUL_F64,  "__mspabi_mpyd", ISD::SETCC_INVALID },
218     { RTLIB::MUL_F32,  "__mspabi_mpyf", ISD::SETCC_INVALID },
219     { RTLIB::SUB_F64,  "__mspabi_subd", ISD::SETCC_INVALID },
220     { RTLIB::SUB_F32,  "__mspabi_subf", ISD::SETCC_INVALID },
221     // The following are NOT implemented in libgcc
222     // { RTLIB::NEG_F64,  "__mspabi_negd", ISD::SETCC_INVALID },
223     // { RTLIB::NEG_F32,  "__mspabi_negf", ISD::SETCC_INVALID },
224 
225     // Universal Integer Operations - EABI Table 9
226     { RTLIB::SDIV_I16,   "__mspabi_divi", ISD::SETCC_INVALID },
227     { RTLIB::SDIV_I32,   "__mspabi_divli", ISD::SETCC_INVALID },
228     { RTLIB::SDIV_I64,   "__mspabi_divlli", ISD::SETCC_INVALID },
229     { RTLIB::UDIV_I16,   "__mspabi_divu", ISD::SETCC_INVALID },
230     { RTLIB::UDIV_I32,   "__mspabi_divul", ISD::SETCC_INVALID },
231     { RTLIB::UDIV_I64,   "__mspabi_divull", ISD::SETCC_INVALID },
232     { RTLIB::SREM_I16,   "__mspabi_remi", ISD::SETCC_INVALID },
233     { RTLIB::SREM_I32,   "__mspabi_remli", ISD::SETCC_INVALID },
234     { RTLIB::SREM_I64,   "__mspabi_remlli", ISD::SETCC_INVALID },
235     { RTLIB::UREM_I16,   "__mspabi_remu", ISD::SETCC_INVALID },
236     { RTLIB::UREM_I32,   "__mspabi_remul", ISD::SETCC_INVALID },
237     { RTLIB::UREM_I64,   "__mspabi_remull", ISD::SETCC_INVALID },
238 
239     // Bitwise Operations - EABI Table 10
240     // TODO: __mspabi_[srli/srai/slli] ARE implemented in libgcc
241     { RTLIB::SRL_I32,    "__mspabi_srll", ISD::SETCC_INVALID },
242     { RTLIB::SRA_I32,    "__mspabi_sral", ISD::SETCC_INVALID },
243     { RTLIB::SHL_I32,    "__mspabi_slll", ISD::SETCC_INVALID },
244     // __mspabi_[srlll/srall/sllll/rlli/rlll] are NOT implemented in libgcc
245 
246   };
247 
248   for (const auto &LC : LibraryCalls) {
249     setLibcallName(LC.Op, LC.Name);
250     if (LC.Cond != ISD::SETCC_INVALID)
251       setCmpLibcallCC(LC.Op, LC.Cond);
252   }
253 
254   if (STI.hasHWMult16()) {
255     const struct {
256       const RTLIB::Libcall Op;
257       const char * const Name;
258     } LibraryCalls[] = {
259       // Integer Multiply - EABI Table 9
260       { RTLIB::MUL_I16,   "__mspabi_mpyi_hw" },
261       { RTLIB::MUL_I32,   "__mspabi_mpyl_hw" },
262       { RTLIB::MUL_I64,   "__mspabi_mpyll_hw" },
263       // TODO The __mspabi_mpysl*_hw functions ARE implemented in libgcc
264       // TODO The __mspabi_mpyul*_hw functions ARE implemented in libgcc
265     };
266     for (const auto &LC : LibraryCalls) {
267       setLibcallName(LC.Op, LC.Name);
268     }
269   } else if (STI.hasHWMult32()) {
270     const struct {
271       const RTLIB::Libcall Op;
272       const char * const Name;
273     } LibraryCalls[] = {
274       // Integer Multiply - EABI Table 9
275       { RTLIB::MUL_I16,   "__mspabi_mpyi_hw" },
276       { RTLIB::MUL_I32,   "__mspabi_mpyl_hw32" },
277       { RTLIB::MUL_I64,   "__mspabi_mpyll_hw32" },
278       // TODO The __mspabi_mpysl*_hw32 functions ARE implemented in libgcc
279       // TODO The __mspabi_mpyul*_hw32 functions ARE implemented in libgcc
280     };
281     for (const auto &LC : LibraryCalls) {
282       setLibcallName(LC.Op, LC.Name);
283     }
284   } else if (STI.hasHWMultF5()) {
285     const struct {
286       const RTLIB::Libcall Op;
287       const char * const Name;
288     } LibraryCalls[] = {
289       // Integer Multiply - EABI Table 9
290       { RTLIB::MUL_I16,   "__mspabi_mpyi_f5hw" },
291       { RTLIB::MUL_I32,   "__mspabi_mpyl_f5hw" },
292       { RTLIB::MUL_I64,   "__mspabi_mpyll_f5hw" },
293       // TODO The __mspabi_mpysl*_f5hw functions ARE implemented in libgcc
294       // TODO The __mspabi_mpyul*_f5hw functions ARE implemented in libgcc
295     };
296     for (const auto &LC : LibraryCalls) {
297       setLibcallName(LC.Op, LC.Name);
298     }
299   } else { // NoHWMult
300     const struct {
301       const RTLIB::Libcall Op;
302       const char * const Name;
303     } LibraryCalls[] = {
304       // Integer Multiply - EABI Table 9
305       { RTLIB::MUL_I16,   "__mspabi_mpyi" },
306       { RTLIB::MUL_I32,   "__mspabi_mpyl" },
307       { RTLIB::MUL_I64,   "__mspabi_mpyll" },
308       // The __mspabi_mpysl* functions are NOT implemented in libgcc
309       // The __mspabi_mpyul* functions are NOT implemented in libgcc
310     };
311     for (const auto &LC : LibraryCalls) {
312       setLibcallName(LC.Op, LC.Name);
313     }
314     setLibcallCallingConv(RTLIB::MUL_I64, CallingConv::MSP430_BUILTIN);
315   }
316 
317   // Several of the runtime library functions use a special calling conv
318   setLibcallCallingConv(RTLIB::UDIV_I64, CallingConv::MSP430_BUILTIN);
319   setLibcallCallingConv(RTLIB::UREM_I64, CallingConv::MSP430_BUILTIN);
320   setLibcallCallingConv(RTLIB::SDIV_I64, CallingConv::MSP430_BUILTIN);
321   setLibcallCallingConv(RTLIB::SREM_I64, CallingConv::MSP430_BUILTIN);
322   setLibcallCallingConv(RTLIB::ADD_F64, CallingConv::MSP430_BUILTIN);
323   setLibcallCallingConv(RTLIB::SUB_F64, CallingConv::MSP430_BUILTIN);
324   setLibcallCallingConv(RTLIB::MUL_F64, CallingConv::MSP430_BUILTIN);
325   setLibcallCallingConv(RTLIB::DIV_F64, CallingConv::MSP430_BUILTIN);
326   setLibcallCallingConv(RTLIB::OEQ_F64, CallingConv::MSP430_BUILTIN);
327   setLibcallCallingConv(RTLIB::UNE_F64, CallingConv::MSP430_BUILTIN);
328   setLibcallCallingConv(RTLIB::OGE_F64, CallingConv::MSP430_BUILTIN);
329   setLibcallCallingConv(RTLIB::OLT_F64, CallingConv::MSP430_BUILTIN);
330   setLibcallCallingConv(RTLIB::OLE_F64, CallingConv::MSP430_BUILTIN);
331   setLibcallCallingConv(RTLIB::OGT_F64, CallingConv::MSP430_BUILTIN);
332   // TODO: __mspabi_srall, __mspabi_srlll, __mspabi_sllll
333 
334   setMinFunctionAlignment(Align(2));
335   setPrefFunctionAlignment(Align(2));
336   setMaxAtomicSizeInBitsSupported(0);
337 }
338 
339 SDValue MSP430TargetLowering::LowerOperation(SDValue Op,
340                                              SelectionDAG &DAG) const {
341   switch (Op.getOpcode()) {
342   case ISD::SHL: // FALLTHROUGH
343   case ISD::SRL:
344   case ISD::SRA:              return LowerShifts(Op, DAG);
345   case ISD::GlobalAddress:    return LowerGlobalAddress(Op, DAG);
346   case ISD::BlockAddress:     return LowerBlockAddress(Op, DAG);
347   case ISD::ExternalSymbol:   return LowerExternalSymbol(Op, DAG);
348   case ISD::SETCC:            return LowerSETCC(Op, DAG);
349   case ISD::BR_CC:            return LowerBR_CC(Op, DAG);
350   case ISD::SELECT_CC:        return LowerSELECT_CC(Op, DAG);
351   case ISD::SIGN_EXTEND:      return LowerSIGN_EXTEND(Op, DAG);
352   case ISD::RETURNADDR:       return LowerRETURNADDR(Op, DAG);
353   case ISD::FRAMEADDR:        return LowerFRAMEADDR(Op, DAG);
354   case ISD::VASTART:          return LowerVASTART(Op, DAG);
355   case ISD::JumpTable:        return LowerJumpTable(Op, DAG);
356   default:
357     llvm_unreachable("unimplemented operand");
358   }
359 }
360 
361 // Define non profitable transforms into shifts
362 bool MSP430TargetLowering::shouldAvoidTransformToShift(EVT VT,
363                                                        unsigned Amount) const {
364   return !(Amount == 8 || Amount == 9 || Amount<=2);
365 }
366 
367 // Implemented to verify test case assertions in
368 // tests/codegen/msp430/shift-amount-threshold-b.ll
369 bool MSP430TargetLowering::isLegalICmpImmediate(int64_t Immed) const {
370   if (MSP430NoLegalImmediate)
371     return Immed >= -32 && Immed < 32;
372   return TargetLowering::isLegalICmpImmediate(Immed);
373 }
374 
375 //===----------------------------------------------------------------------===//
376 //                       MSP430 Inline Assembly Support
377 //===----------------------------------------------------------------------===//
378 
379 /// getConstraintType - Given a constraint letter, return the type of
380 /// constraint it is for this target.
381 TargetLowering::ConstraintType
382 MSP430TargetLowering::getConstraintType(StringRef Constraint) const {
383   if (Constraint.size() == 1) {
384     switch (Constraint[0]) {
385     case 'r':
386       return C_RegisterClass;
387     default:
388       break;
389     }
390   }
391   return TargetLowering::getConstraintType(Constraint);
392 }
393 
394 std::pair<unsigned, const TargetRegisterClass *>
395 MSP430TargetLowering::getRegForInlineAsmConstraint(
396     const TargetRegisterInfo *TRI, StringRef Constraint, MVT VT) const {
397   if (Constraint.size() == 1) {
398     // GCC Constraint Letters
399     switch (Constraint[0]) {
400     default: break;
401     case 'r':   // GENERAL_REGS
402       if (VT == MVT::i8)
403         return std::make_pair(0U, &MSP430::GR8RegClass);
404 
405       return std::make_pair(0U, &MSP430::GR16RegClass);
406     }
407   }
408 
409   return TargetLowering::getRegForInlineAsmConstraint(TRI, Constraint, VT);
410 }
411 
412 //===----------------------------------------------------------------------===//
413 //                      Calling Convention Implementation
414 //===----------------------------------------------------------------------===//
415 
416 #include "MSP430GenCallingConv.inc"
417 
418 /// For each argument in a function store the number of pieces it is composed
419 /// of.
420 template<typename ArgT>
421 static void ParseFunctionArgs(const SmallVectorImpl<ArgT> &Args,
422                               SmallVectorImpl<unsigned> &Out) {
423   unsigned CurrentArgIndex;
424 
425   if (Args.empty())
426     return;
427 
428   CurrentArgIndex = Args[0].OrigArgIndex;
429   Out.push_back(0);
430 
431   for (auto &Arg : Args) {
432     if (CurrentArgIndex == Arg.OrigArgIndex) {
433       Out.back() += 1;
434     } else {
435       Out.push_back(1);
436       CurrentArgIndex = Arg.OrigArgIndex;
437     }
438   }
439 }
440 
441 static void AnalyzeVarArgs(CCState &State,
442                            const SmallVectorImpl<ISD::OutputArg> &Outs) {
443   State.AnalyzeCallOperands(Outs, CC_MSP430_AssignStack);
444 }
445 
446 static void AnalyzeVarArgs(CCState &State,
447                            const SmallVectorImpl<ISD::InputArg> &Ins) {
448   State.AnalyzeFormalArguments(Ins, CC_MSP430_AssignStack);
449 }
450 
451 /// Analyze incoming and outgoing function arguments. We need custom C++ code
452 /// to handle special constraints in the ABI like reversing the order of the
453 /// pieces of splitted arguments. In addition, all pieces of a certain argument
454 /// have to be passed either using registers or the stack but never mixing both.
455 template<typename ArgT>
456 static void AnalyzeArguments(CCState &State,
457                              SmallVectorImpl<CCValAssign> &ArgLocs,
458                              const SmallVectorImpl<ArgT> &Args) {
459   static const MCPhysReg CRegList[] = {
460     MSP430::R12, MSP430::R13, MSP430::R14, MSP430::R15
461   };
462   static const unsigned CNbRegs = std::size(CRegList);
463   static const MCPhysReg BuiltinRegList[] = {
464     MSP430::R8, MSP430::R9, MSP430::R10, MSP430::R11,
465     MSP430::R12, MSP430::R13, MSP430::R14, MSP430::R15
466   };
467   static const unsigned BuiltinNbRegs = std::size(BuiltinRegList);
468 
469   ArrayRef<MCPhysReg> RegList;
470   unsigned NbRegs;
471 
472   bool Builtin = (State.getCallingConv() == CallingConv::MSP430_BUILTIN);
473   if (Builtin) {
474     RegList = BuiltinRegList;
475     NbRegs = BuiltinNbRegs;
476   } else {
477     RegList = CRegList;
478     NbRegs = CNbRegs;
479   }
480 
481   if (State.isVarArg()) {
482     AnalyzeVarArgs(State, Args);
483     return;
484   }
485 
486   SmallVector<unsigned, 4> ArgsParts;
487   ParseFunctionArgs(Args, ArgsParts);
488 
489   if (Builtin) {
490     assert(ArgsParts.size() == 2 &&
491         "Builtin calling convention requires two arguments");
492   }
493 
494   unsigned RegsLeft = NbRegs;
495   bool UsedStack = false;
496   unsigned ValNo = 0;
497 
498   for (unsigned i = 0, e = ArgsParts.size(); i != e; i++) {
499     MVT ArgVT = Args[ValNo].VT;
500     ISD::ArgFlagsTy ArgFlags = Args[ValNo].Flags;
501     MVT LocVT = ArgVT;
502     CCValAssign::LocInfo LocInfo = CCValAssign::Full;
503 
504     // Promote i8 to i16
505     if (LocVT == MVT::i8) {
506       LocVT = MVT::i16;
507       if (ArgFlags.isSExt())
508           LocInfo = CCValAssign::SExt;
509       else if (ArgFlags.isZExt())
510           LocInfo = CCValAssign::ZExt;
511       else
512           LocInfo = CCValAssign::AExt;
513     }
514 
515     // Handle byval arguments
516     if (ArgFlags.isByVal()) {
517       State.HandleByVal(ValNo++, ArgVT, LocVT, LocInfo, 2, Align(2), ArgFlags);
518       continue;
519     }
520 
521     unsigned Parts = ArgsParts[i];
522 
523     if (Builtin) {
524       assert(Parts == 4 &&
525           "Builtin calling convention requires 64-bit arguments");
526     }
527 
528     if (!UsedStack && Parts == 2 && RegsLeft == 1) {
529       // Special case for 32-bit register split, see EABI section 3.3.3
530       unsigned Reg = State.AllocateReg(RegList);
531       State.addLoc(CCValAssign::getReg(ValNo++, ArgVT, Reg, LocVT, LocInfo));
532       RegsLeft -= 1;
533 
534       UsedStack = true;
535       CC_MSP430_AssignStack(ValNo++, ArgVT, LocVT, LocInfo, ArgFlags, State);
536     } else if (Parts <= RegsLeft) {
537       for (unsigned j = 0; j < Parts; j++) {
538         unsigned Reg = State.AllocateReg(RegList);
539         State.addLoc(CCValAssign::getReg(ValNo++, ArgVT, Reg, LocVT, LocInfo));
540         RegsLeft--;
541       }
542     } else {
543       UsedStack = true;
544       for (unsigned j = 0; j < Parts; j++)
545         CC_MSP430_AssignStack(ValNo++, ArgVT, LocVT, LocInfo, ArgFlags, State);
546     }
547   }
548 }
549 
550 static void AnalyzeRetResult(CCState &State,
551                              const SmallVectorImpl<ISD::InputArg> &Ins) {
552   State.AnalyzeCallResult(Ins, RetCC_MSP430);
553 }
554 
555 static void AnalyzeRetResult(CCState &State,
556                              const SmallVectorImpl<ISD::OutputArg> &Outs) {
557   State.AnalyzeReturn(Outs, RetCC_MSP430);
558 }
559 
560 template<typename ArgT>
561 static void AnalyzeReturnValues(CCState &State,
562                                 SmallVectorImpl<CCValAssign> &RVLocs,
563                                 const SmallVectorImpl<ArgT> &Args) {
564   AnalyzeRetResult(State, Args);
565 }
566 
567 SDValue MSP430TargetLowering::LowerFormalArguments(
568     SDValue Chain, CallingConv::ID CallConv, bool isVarArg,
569     const SmallVectorImpl<ISD::InputArg> &Ins, const SDLoc &dl,
570     SelectionDAG &DAG, SmallVectorImpl<SDValue> &InVals) const {
571 
572   switch (CallConv) {
573   default:
574     report_fatal_error("Unsupported calling convention");
575   case CallingConv::C:
576   case CallingConv::Fast:
577     return LowerCCCArguments(Chain, CallConv, isVarArg, Ins, dl, DAG, InVals);
578   case CallingConv::MSP430_INTR:
579     if (Ins.empty())
580       return Chain;
581     report_fatal_error("ISRs cannot have arguments");
582   }
583 }
584 
585 SDValue
586 MSP430TargetLowering::LowerCall(TargetLowering::CallLoweringInfo &CLI,
587                                 SmallVectorImpl<SDValue> &InVals) const {
588   SelectionDAG &DAG                     = CLI.DAG;
589   SDLoc &dl                             = CLI.DL;
590   SmallVectorImpl<ISD::OutputArg> &Outs = CLI.Outs;
591   SmallVectorImpl<SDValue> &OutVals     = CLI.OutVals;
592   SmallVectorImpl<ISD::InputArg> &Ins   = CLI.Ins;
593   SDValue Chain                         = CLI.Chain;
594   SDValue Callee                        = CLI.Callee;
595   bool &isTailCall                      = CLI.IsTailCall;
596   CallingConv::ID CallConv              = CLI.CallConv;
597   bool isVarArg                         = CLI.IsVarArg;
598 
599   // MSP430 target does not yet support tail call optimization.
600   isTailCall = false;
601 
602   switch (CallConv) {
603   default:
604     report_fatal_error("Unsupported calling convention");
605   case CallingConv::MSP430_BUILTIN:
606   case CallingConv::Fast:
607   case CallingConv::C:
608     return LowerCCCCallTo(Chain, Callee, CallConv, isVarArg, isTailCall,
609                           Outs, OutVals, Ins, dl, DAG, InVals);
610   case CallingConv::MSP430_INTR:
611     report_fatal_error("ISRs cannot be called directly");
612   }
613 }
614 
615 /// LowerCCCArguments - transform physical registers into virtual registers and
616 /// generate load operations for arguments places on the stack.
617 // FIXME: struct return stuff
618 SDValue MSP430TargetLowering::LowerCCCArguments(
619     SDValue Chain, CallingConv::ID CallConv, bool isVarArg,
620     const SmallVectorImpl<ISD::InputArg> &Ins, const SDLoc &dl,
621     SelectionDAG &DAG, SmallVectorImpl<SDValue> &InVals) const {
622   MachineFunction &MF = DAG.getMachineFunction();
623   MachineFrameInfo &MFI = MF.getFrameInfo();
624   MachineRegisterInfo &RegInfo = MF.getRegInfo();
625   MSP430MachineFunctionInfo *FuncInfo = MF.getInfo<MSP430MachineFunctionInfo>();
626 
627   // Assign locations to all of the incoming arguments.
628   SmallVector<CCValAssign, 16> ArgLocs;
629   CCState CCInfo(CallConv, isVarArg, DAG.getMachineFunction(), ArgLocs,
630                  *DAG.getContext());
631   AnalyzeArguments(CCInfo, ArgLocs, Ins);
632 
633   // Create frame index for the start of the first vararg value
634   if (isVarArg) {
635     unsigned Offset = CCInfo.getStackSize();
636     FuncInfo->setVarArgsFrameIndex(MFI.CreateFixedObject(1, Offset, true));
637   }
638 
639   for (unsigned i = 0, e = ArgLocs.size(); i != e; ++i) {
640     CCValAssign &VA = ArgLocs[i];
641     if (VA.isRegLoc()) {
642       // Arguments passed in registers
643       EVT RegVT = VA.getLocVT();
644       switch (RegVT.getSimpleVT().SimpleTy) {
645       default:
646         {
647 #ifndef NDEBUG
648           errs() << "LowerFormalArguments Unhandled argument type: "
649                  << RegVT << "\n";
650 #endif
651           llvm_unreachable(nullptr);
652         }
653       case MVT::i16:
654         Register VReg = RegInfo.createVirtualRegister(&MSP430::GR16RegClass);
655         RegInfo.addLiveIn(VA.getLocReg(), VReg);
656         SDValue ArgValue = DAG.getCopyFromReg(Chain, dl, VReg, RegVT);
657 
658         // If this is an 8-bit value, it is really passed promoted to 16
659         // bits. Insert an assert[sz]ext to capture this, then truncate to the
660         // right size.
661         if (VA.getLocInfo() == CCValAssign::SExt)
662           ArgValue = DAG.getNode(ISD::AssertSext, dl, RegVT, ArgValue,
663                                  DAG.getValueType(VA.getValVT()));
664         else if (VA.getLocInfo() == CCValAssign::ZExt)
665           ArgValue = DAG.getNode(ISD::AssertZext, dl, RegVT, ArgValue,
666                                  DAG.getValueType(VA.getValVT()));
667 
668         if (VA.getLocInfo() != CCValAssign::Full)
669           ArgValue = DAG.getNode(ISD::TRUNCATE, dl, VA.getValVT(), ArgValue);
670 
671         InVals.push_back(ArgValue);
672       }
673     } else {
674       // Only arguments passed on the stack should make it here.
675       assert(VA.isMemLoc());
676 
677       SDValue InVal;
678       ISD::ArgFlagsTy Flags = Ins[i].Flags;
679 
680       if (Flags.isByVal()) {
681         MVT PtrVT = VA.getLocVT();
682         int FI = MFI.CreateFixedObject(Flags.getByValSize(),
683                                        VA.getLocMemOffset(), true);
684         InVal = DAG.getFrameIndex(FI, PtrVT);
685       } else {
686         // Load the argument to a virtual register
687         unsigned ObjSize = VA.getLocVT().getSizeInBits()/8;
688         if (ObjSize > 2) {
689             errs() << "LowerFormalArguments Unhandled argument type: "
690                 << VA.getLocVT() << "\n";
691         }
692         // Create the frame index object for this incoming parameter...
693         int FI = MFI.CreateFixedObject(ObjSize, VA.getLocMemOffset(), true);
694 
695         // Create the SelectionDAG nodes corresponding to a load
696         //from this parameter
697         SDValue FIN = DAG.getFrameIndex(FI, MVT::i16);
698         InVal = DAG.getLoad(
699             VA.getLocVT(), dl, Chain, FIN,
700             MachinePointerInfo::getFixedStack(DAG.getMachineFunction(), FI));
701       }
702 
703       InVals.push_back(InVal);
704     }
705   }
706 
707   for (unsigned i = 0, e = ArgLocs.size(); i != e; ++i) {
708     if (Ins[i].Flags.isSRet()) {
709       Register Reg = FuncInfo->getSRetReturnReg();
710       if (!Reg) {
711         Reg = MF.getRegInfo().createVirtualRegister(
712             getRegClassFor(MVT::i16));
713         FuncInfo->setSRetReturnReg(Reg);
714       }
715       SDValue Copy = DAG.getCopyToReg(DAG.getEntryNode(), dl, Reg, InVals[i]);
716       Chain = DAG.getNode(ISD::TokenFactor, dl, MVT::Other, Copy, Chain);
717     }
718   }
719 
720   return Chain;
721 }
722 
723 bool
724 MSP430TargetLowering::CanLowerReturn(CallingConv::ID CallConv,
725                                      MachineFunction &MF,
726                                      bool IsVarArg,
727                                      const SmallVectorImpl<ISD::OutputArg> &Outs,
728                                      LLVMContext &Context) const {
729   SmallVector<CCValAssign, 16> RVLocs;
730   CCState CCInfo(CallConv, IsVarArg, MF, RVLocs, Context);
731   return CCInfo.CheckReturn(Outs, RetCC_MSP430);
732 }
733 
734 SDValue
735 MSP430TargetLowering::LowerReturn(SDValue Chain, CallingConv::ID CallConv,
736                                   bool isVarArg,
737                                   const SmallVectorImpl<ISD::OutputArg> &Outs,
738                                   const SmallVectorImpl<SDValue> &OutVals,
739                                   const SDLoc &dl, SelectionDAG &DAG) const {
740 
741   MachineFunction &MF = DAG.getMachineFunction();
742 
743   // CCValAssign - represent the assignment of the return value to a location
744   SmallVector<CCValAssign, 16> RVLocs;
745 
746   // ISRs cannot return any value.
747   if (CallConv == CallingConv::MSP430_INTR && !Outs.empty())
748     report_fatal_error("ISRs cannot return any value");
749 
750   // CCState - Info about the registers and stack slot.
751   CCState CCInfo(CallConv, isVarArg, DAG.getMachineFunction(), RVLocs,
752                  *DAG.getContext());
753 
754   // Analize return values.
755   AnalyzeReturnValues(CCInfo, RVLocs, Outs);
756 
757   SDValue Glue;
758   SmallVector<SDValue, 4> RetOps(1, Chain);
759 
760   // Copy the result values into the output registers.
761   for (unsigned i = 0; i != RVLocs.size(); ++i) {
762     CCValAssign &VA = RVLocs[i];
763     assert(VA.isRegLoc() && "Can only return in registers!");
764 
765     Chain = DAG.getCopyToReg(Chain, dl, VA.getLocReg(),
766                              OutVals[i], Glue);
767 
768     // Guarantee that all emitted copies are stuck together,
769     // avoiding something bad.
770     Glue = Chain.getValue(1);
771     RetOps.push_back(DAG.getRegister(VA.getLocReg(), VA.getLocVT()));
772   }
773 
774   if (MF.getFunction().hasStructRetAttr()) {
775     MSP430MachineFunctionInfo *FuncInfo = MF.getInfo<MSP430MachineFunctionInfo>();
776     Register Reg = FuncInfo->getSRetReturnReg();
777 
778     if (!Reg)
779       llvm_unreachable("sret virtual register not created in entry block");
780 
781     MVT PtrVT = getFrameIndexTy(DAG.getDataLayout());
782     SDValue Val =
783       DAG.getCopyFromReg(Chain, dl, Reg, PtrVT);
784     unsigned R12 = MSP430::R12;
785 
786     Chain = DAG.getCopyToReg(Chain, dl, R12, Val, Glue);
787     Glue = Chain.getValue(1);
788     RetOps.push_back(DAG.getRegister(R12, PtrVT));
789   }
790 
791   unsigned Opc = (CallConv == CallingConv::MSP430_INTR ?
792                   MSP430ISD::RETI_GLUE : MSP430ISD::RET_GLUE);
793 
794   RetOps[0] = Chain;  // Update chain.
795 
796   // Add the glue if we have it.
797   if (Glue.getNode())
798     RetOps.push_back(Glue);
799 
800   return DAG.getNode(Opc, dl, MVT::Other, RetOps);
801 }
802 
803 /// LowerCCCCallTo - functions arguments are copied from virtual regs to
804 /// (physical regs)/(stack frame), CALLSEQ_START and CALLSEQ_END are emitted.
805 SDValue MSP430TargetLowering::LowerCCCCallTo(
806     SDValue Chain, SDValue Callee, CallingConv::ID CallConv, bool isVarArg,
807     bool isTailCall, const SmallVectorImpl<ISD::OutputArg> &Outs,
808     const SmallVectorImpl<SDValue> &OutVals,
809     const SmallVectorImpl<ISD::InputArg> &Ins, const SDLoc &dl,
810     SelectionDAG &DAG, SmallVectorImpl<SDValue> &InVals) const {
811   // Analyze operands of the call, assigning locations to each operand.
812   SmallVector<CCValAssign, 16> ArgLocs;
813   CCState CCInfo(CallConv, isVarArg, DAG.getMachineFunction(), ArgLocs,
814                  *DAG.getContext());
815   AnalyzeArguments(CCInfo, ArgLocs, Outs);
816 
817   // Get a count of how many bytes are to be pushed on the stack.
818   unsigned NumBytes = CCInfo.getStackSize();
819   MVT PtrVT = getFrameIndexTy(DAG.getDataLayout());
820 
821   Chain = DAG.getCALLSEQ_START(Chain, NumBytes, 0, dl);
822 
823   SmallVector<std::pair<unsigned, SDValue>, 4> RegsToPass;
824   SmallVector<SDValue, 12> MemOpChains;
825   SDValue StackPtr;
826 
827   // Walk the register/memloc assignments, inserting copies/loads.
828   for (unsigned i = 0, e = ArgLocs.size(); i != e; ++i) {
829     CCValAssign &VA = ArgLocs[i];
830 
831     SDValue Arg = OutVals[i];
832 
833     // Promote the value if needed.
834     switch (VA.getLocInfo()) {
835       default: llvm_unreachable("Unknown loc info!");
836       case CCValAssign::Full: break;
837       case CCValAssign::SExt:
838         Arg = DAG.getNode(ISD::SIGN_EXTEND, dl, VA.getLocVT(), Arg);
839         break;
840       case CCValAssign::ZExt:
841         Arg = DAG.getNode(ISD::ZERO_EXTEND, dl, VA.getLocVT(), Arg);
842         break;
843       case CCValAssign::AExt:
844         Arg = DAG.getNode(ISD::ANY_EXTEND, dl, VA.getLocVT(), Arg);
845         break;
846     }
847 
848     // Arguments that can be passed on register must be kept at RegsToPass
849     // vector
850     if (VA.isRegLoc()) {
851       RegsToPass.push_back(std::make_pair(VA.getLocReg(), Arg));
852     } else {
853       assert(VA.isMemLoc());
854 
855       if (!StackPtr.getNode())
856         StackPtr = DAG.getCopyFromReg(Chain, dl, MSP430::SP, PtrVT);
857 
858       SDValue PtrOff =
859           DAG.getNode(ISD::ADD, dl, PtrVT, StackPtr,
860                       DAG.getIntPtrConstant(VA.getLocMemOffset(), dl));
861 
862       SDValue MemOp;
863       ISD::ArgFlagsTy Flags = Outs[i].Flags;
864 
865       if (Flags.isByVal()) {
866         SDValue SizeNode = DAG.getConstant(Flags.getByValSize(), dl, MVT::i16);
867         MemOp = DAG.getMemcpy(
868             Chain, dl, PtrOff, Arg, SizeNode, Flags.getNonZeroByValAlign(),
869             /*isVolatile*/ false,
870             /*AlwaysInline=*/true,
871             /*isTailCall=*/false, MachinePointerInfo(), MachinePointerInfo());
872       } else {
873         MemOp = DAG.getStore(Chain, dl, Arg, PtrOff, MachinePointerInfo());
874       }
875 
876       MemOpChains.push_back(MemOp);
877     }
878   }
879 
880   // Transform all store nodes into one single node because all store nodes are
881   // independent of each other.
882   if (!MemOpChains.empty())
883     Chain = DAG.getNode(ISD::TokenFactor, dl, MVT::Other, MemOpChains);
884 
885   // Build a sequence of copy-to-reg nodes chained together with token chain and
886   // flag operands which copy the outgoing args into registers.  The InGlue in
887   // necessary since all emitted instructions must be stuck together.
888   SDValue InGlue;
889   for (unsigned i = 0, e = RegsToPass.size(); i != e; ++i) {
890     Chain = DAG.getCopyToReg(Chain, dl, RegsToPass[i].first,
891                              RegsToPass[i].second, InGlue);
892     InGlue = Chain.getValue(1);
893   }
894 
895   // If the callee is a GlobalAddress node (quite common, every direct call is)
896   // turn it into a TargetGlobalAddress node so that legalize doesn't hack it.
897   // Likewise ExternalSymbol -> TargetExternalSymbol.
898   if (GlobalAddressSDNode *G = dyn_cast<GlobalAddressSDNode>(Callee))
899     Callee = DAG.getTargetGlobalAddress(G->getGlobal(), dl, MVT::i16);
900   else if (ExternalSymbolSDNode *E = dyn_cast<ExternalSymbolSDNode>(Callee))
901     Callee = DAG.getTargetExternalSymbol(E->getSymbol(), MVT::i16);
902 
903   // Returns a chain & a flag for retval copy to use.
904   SDVTList NodeTys = DAG.getVTList(MVT::Other, MVT::Glue);
905   SmallVector<SDValue, 8> Ops;
906   Ops.push_back(Chain);
907   Ops.push_back(Callee);
908 
909   // Add argument registers to the end of the list so that they are
910   // known live into the call.
911   for (unsigned i = 0, e = RegsToPass.size(); i != e; ++i)
912     Ops.push_back(DAG.getRegister(RegsToPass[i].first,
913                                   RegsToPass[i].second.getValueType()));
914 
915   if (InGlue.getNode())
916     Ops.push_back(InGlue);
917 
918   Chain = DAG.getNode(MSP430ISD::CALL, dl, NodeTys, Ops);
919   InGlue = Chain.getValue(1);
920 
921   // Create the CALLSEQ_END node.
922   Chain = DAG.getCALLSEQ_END(Chain, NumBytes, 0, InGlue, dl);
923   InGlue = Chain.getValue(1);
924 
925   // Handle result values, copying them out of physregs into vregs that we
926   // return.
927   return LowerCallResult(Chain, InGlue, CallConv, isVarArg, Ins, dl,
928                          DAG, InVals);
929 }
930 
931 /// LowerCallResult - Lower the result values of a call into the
932 /// appropriate copies out of appropriate physical registers.
933 ///
934 SDValue MSP430TargetLowering::LowerCallResult(
935     SDValue Chain, SDValue InGlue, CallingConv::ID CallConv, bool isVarArg,
936     const SmallVectorImpl<ISD::InputArg> &Ins, const SDLoc &dl,
937     SelectionDAG &DAG, SmallVectorImpl<SDValue> &InVals) const {
938 
939   // Assign locations to each value returned by this call.
940   SmallVector<CCValAssign, 16> RVLocs;
941   CCState CCInfo(CallConv, isVarArg, DAG.getMachineFunction(), RVLocs,
942                  *DAG.getContext());
943 
944   AnalyzeReturnValues(CCInfo, RVLocs, Ins);
945 
946   // Copy all of the result registers out of their specified physreg.
947   for (unsigned i = 0; i != RVLocs.size(); ++i) {
948     Chain = DAG.getCopyFromReg(Chain, dl, RVLocs[i].getLocReg(),
949                                RVLocs[i].getValVT(), InGlue).getValue(1);
950     InGlue = Chain.getValue(2);
951     InVals.push_back(Chain.getValue(0));
952   }
953 
954   return Chain;
955 }
956 
957 SDValue MSP430TargetLowering::LowerShifts(SDValue Op,
958                                           SelectionDAG &DAG) const {
959   unsigned Opc = Op.getOpcode();
960   SDNode* N = Op.getNode();
961   EVT VT = Op.getValueType();
962   SDLoc dl(N);
963 
964   // Expand non-constant shifts to loops:
965   if (!isa<ConstantSDNode>(N->getOperand(1)))
966     return Op;
967 
968   uint64_t ShiftAmount = N->getConstantOperandVal(1);
969 
970   // Expand the stuff into sequence of shifts.
971   SDValue Victim = N->getOperand(0);
972 
973   if (ShiftAmount >= 8) {
974     assert(VT == MVT::i16 && "Can not shift i8 by 8 and more");
975     switch(Opc) {
976     default:
977       llvm_unreachable("Unknown shift");
978     case ISD::SHL:
979       // foo << (8 + N) => swpb(zext(foo)) << N
980       Victim = DAG.getZeroExtendInReg(Victim, dl, MVT::i8);
981       Victim = DAG.getNode(ISD::BSWAP, dl, VT, Victim);
982       break;
983     case ISD::SRA:
984     case ISD::SRL:
985       // foo >> (8 + N) => sxt(swpb(foo)) >> N
986       Victim = DAG.getNode(ISD::BSWAP, dl, VT, Victim);
987       Victim = (Opc == ISD::SRA)
988                    ? DAG.getNode(ISD::SIGN_EXTEND_INREG, dl, VT, Victim,
989                                  DAG.getValueType(MVT::i8))
990                    : DAG.getZeroExtendInReg(Victim, dl, MVT::i8);
991       break;
992     }
993     ShiftAmount -= 8;
994   }
995 
996   if (Opc == ISD::SRL && ShiftAmount) {
997     // Emit a special goodness here:
998     // srl A, 1 => clrc; rrc A
999     Victim = DAG.getNode(MSP430ISD::RRCL, dl, VT, Victim);
1000     ShiftAmount -= 1;
1001   }
1002 
1003   while (ShiftAmount--)
1004     Victim = DAG.getNode((Opc == ISD::SHL ? MSP430ISD::RLA : MSP430ISD::RRA),
1005                          dl, VT, Victim);
1006 
1007   return Victim;
1008 }
1009 
1010 SDValue MSP430TargetLowering::LowerGlobalAddress(SDValue Op,
1011                                                  SelectionDAG &DAG) const {
1012   const GlobalValue *GV = cast<GlobalAddressSDNode>(Op)->getGlobal();
1013   int64_t Offset = cast<GlobalAddressSDNode>(Op)->getOffset();
1014   EVT PtrVT = Op.getValueType();
1015 
1016   // Create the TargetGlobalAddress node, folding in the constant offset.
1017   SDValue Result = DAG.getTargetGlobalAddress(GV, SDLoc(Op), PtrVT, Offset);
1018   return DAG.getNode(MSP430ISD::Wrapper, SDLoc(Op), PtrVT, Result);
1019 }
1020 
1021 SDValue MSP430TargetLowering::LowerExternalSymbol(SDValue Op,
1022                                                   SelectionDAG &DAG) const {
1023   SDLoc dl(Op);
1024   const char *Sym = cast<ExternalSymbolSDNode>(Op)->getSymbol();
1025   EVT PtrVT = Op.getValueType();
1026   SDValue Result = DAG.getTargetExternalSymbol(Sym, PtrVT);
1027 
1028   return DAG.getNode(MSP430ISD::Wrapper, dl, PtrVT, Result);
1029 }
1030 
1031 SDValue MSP430TargetLowering::LowerBlockAddress(SDValue Op,
1032                                                 SelectionDAG &DAG) const {
1033   SDLoc dl(Op);
1034   const BlockAddress *BA = cast<BlockAddressSDNode>(Op)->getBlockAddress();
1035   EVT PtrVT = Op.getValueType();
1036   SDValue Result = DAG.getTargetBlockAddress(BA, PtrVT);
1037 
1038   return DAG.getNode(MSP430ISD::Wrapper, dl, PtrVT, Result);
1039 }
1040 
1041 static SDValue EmitCMP(SDValue &LHS, SDValue &RHS, SDValue &TargetCC,
1042                        ISD::CondCode CC, const SDLoc &dl, SelectionDAG &DAG) {
1043   // FIXME: Handle bittests someday
1044   assert(!LHS.getValueType().isFloatingPoint() && "We don't handle FP yet");
1045 
1046   // FIXME: Handle jump negative someday
1047   MSP430CC::CondCodes TCC = MSP430CC::COND_INVALID;
1048   switch (CC) {
1049   default: llvm_unreachable("Invalid integer condition!");
1050   case ISD::SETEQ:
1051     TCC = MSP430CC::COND_E;     // aka COND_Z
1052     // Minor optimization: if LHS is a constant, swap operands, then the
1053     // constant can be folded into comparison.
1054     if (LHS.getOpcode() == ISD::Constant)
1055       std::swap(LHS, RHS);
1056     break;
1057   case ISD::SETNE:
1058     TCC = MSP430CC::COND_NE;    // aka COND_NZ
1059     // Minor optimization: if LHS is a constant, swap operands, then the
1060     // constant can be folded into comparison.
1061     if (LHS.getOpcode() == ISD::Constant)
1062       std::swap(LHS, RHS);
1063     break;
1064   case ISD::SETULE:
1065     std::swap(LHS, RHS);
1066     [[fallthrough]];
1067   case ISD::SETUGE:
1068     // Turn lhs u>= rhs with lhs constant into rhs u< lhs+1, this allows us to
1069     // fold constant into instruction.
1070     if (const ConstantSDNode * C = dyn_cast<ConstantSDNode>(LHS)) {
1071       LHS = RHS;
1072       RHS = DAG.getConstant(C->getSExtValue() + 1, dl, C->getValueType(0));
1073       TCC = MSP430CC::COND_LO;
1074       break;
1075     }
1076     TCC = MSP430CC::COND_HS;    // aka COND_C
1077     break;
1078   case ISD::SETUGT:
1079     std::swap(LHS, RHS);
1080     [[fallthrough]];
1081   case ISD::SETULT:
1082     // Turn lhs u< rhs with lhs constant into rhs u>= lhs+1, this allows us to
1083     // fold constant into instruction.
1084     if (const ConstantSDNode * C = dyn_cast<ConstantSDNode>(LHS)) {
1085       LHS = RHS;
1086       RHS = DAG.getConstant(C->getSExtValue() + 1, dl, C->getValueType(0));
1087       TCC = MSP430CC::COND_HS;
1088       break;
1089     }
1090     TCC = MSP430CC::COND_LO;    // aka COND_NC
1091     break;
1092   case ISD::SETLE:
1093     std::swap(LHS, RHS);
1094     [[fallthrough]];
1095   case ISD::SETGE:
1096     // Turn lhs >= rhs with lhs constant into rhs < lhs+1, this allows us to
1097     // fold constant into instruction.
1098     if (const ConstantSDNode * C = dyn_cast<ConstantSDNode>(LHS)) {
1099       LHS = RHS;
1100       RHS = DAG.getConstant(C->getSExtValue() + 1, dl, C->getValueType(0));
1101       TCC = MSP430CC::COND_L;
1102       break;
1103     }
1104     TCC = MSP430CC::COND_GE;
1105     break;
1106   case ISD::SETGT:
1107     std::swap(LHS, RHS);
1108     [[fallthrough]];
1109   case ISD::SETLT:
1110     // Turn lhs < rhs with lhs constant into rhs >= lhs+1, this allows us to
1111     // fold constant into instruction.
1112     if (const ConstantSDNode * C = dyn_cast<ConstantSDNode>(LHS)) {
1113       LHS = RHS;
1114       RHS = DAG.getConstant(C->getSExtValue() + 1, dl, C->getValueType(0));
1115       TCC = MSP430CC::COND_GE;
1116       break;
1117     }
1118     TCC = MSP430CC::COND_L;
1119     break;
1120   }
1121 
1122   TargetCC = DAG.getConstant(TCC, dl, MVT::i8);
1123   return DAG.getNode(MSP430ISD::CMP, dl, MVT::Glue, LHS, RHS);
1124 }
1125 
1126 
1127 SDValue MSP430TargetLowering::LowerBR_CC(SDValue Op, SelectionDAG &DAG) const {
1128   SDValue Chain = Op.getOperand(0);
1129   ISD::CondCode CC = cast<CondCodeSDNode>(Op.getOperand(1))->get();
1130   SDValue LHS   = Op.getOperand(2);
1131   SDValue RHS   = Op.getOperand(3);
1132   SDValue Dest  = Op.getOperand(4);
1133   SDLoc dl  (Op);
1134 
1135   SDValue TargetCC;
1136   SDValue Flag = EmitCMP(LHS, RHS, TargetCC, CC, dl, DAG);
1137 
1138   return DAG.getNode(MSP430ISD::BR_CC, dl, Op.getValueType(),
1139                      Chain, Dest, TargetCC, Flag);
1140 }
1141 
1142 SDValue MSP430TargetLowering::LowerSETCC(SDValue Op, SelectionDAG &DAG) const {
1143   SDValue LHS   = Op.getOperand(0);
1144   SDValue RHS   = Op.getOperand(1);
1145   SDLoc dl  (Op);
1146 
1147   // If we are doing an AND and testing against zero, then the CMP
1148   // will not be generated.  The AND (or BIT) will generate the condition codes,
1149   // but they are different from CMP.
1150   // FIXME: since we're doing a post-processing, use a pseudoinstr here, so
1151   // lowering & isel wouldn't diverge.
1152   bool andCC = false;
1153   if (ConstantSDNode *RHSC = dyn_cast<ConstantSDNode>(RHS)) {
1154     if (RHSC->isZero() && LHS.hasOneUse() &&
1155         (LHS.getOpcode() == ISD::AND ||
1156          (LHS.getOpcode() == ISD::TRUNCATE &&
1157           LHS.getOperand(0).getOpcode() == ISD::AND))) {
1158       andCC = true;
1159     }
1160   }
1161   ISD::CondCode CC = cast<CondCodeSDNode>(Op.getOperand(2))->get();
1162   SDValue TargetCC;
1163   SDValue Flag = EmitCMP(LHS, RHS, TargetCC, CC, dl, DAG);
1164 
1165   // Get the condition codes directly from the status register, if its easy.
1166   // Otherwise a branch will be generated.  Note that the AND and BIT
1167   // instructions generate different flags than CMP, the carry bit can be used
1168   // for NE/EQ.
1169   bool Invert = false;
1170   bool Shift = false;
1171   bool Convert = true;
1172   switch (TargetCC->getAsZExtVal()) {
1173   default:
1174     Convert = false;
1175     break;
1176    case MSP430CC::COND_HS:
1177      // Res = SR & 1, no processing is required
1178      break;
1179    case MSP430CC::COND_LO:
1180      // Res = ~(SR & 1)
1181      Invert = true;
1182      break;
1183    case MSP430CC::COND_NE:
1184      if (andCC) {
1185        // C = ~Z, thus Res = SR & 1, no processing is required
1186      } else {
1187        // Res = ~((SR >> 1) & 1)
1188        Shift = true;
1189        Invert = true;
1190      }
1191      break;
1192    case MSP430CC::COND_E:
1193      Shift = true;
1194      // C = ~Z for AND instruction, thus we can put Res = ~(SR & 1), however,
1195      // Res = (SR >> 1) & 1 is 1 word shorter.
1196      break;
1197    }
1198   EVT VT = Op.getValueType();
1199   SDValue One  = DAG.getConstant(1, dl, VT);
1200   if (Convert) {
1201     SDValue SR = DAG.getCopyFromReg(DAG.getEntryNode(), dl, MSP430::SR,
1202                                     MVT::i16, Flag);
1203     if (Shift)
1204       // FIXME: somewhere this is turned into a SRL, lower it MSP specific?
1205       SR = DAG.getNode(ISD::SRA, dl, MVT::i16, SR, One);
1206     SR = DAG.getNode(ISD::AND, dl, MVT::i16, SR, One);
1207     if (Invert)
1208       SR = DAG.getNode(ISD::XOR, dl, MVT::i16, SR, One);
1209     return SR;
1210   } else {
1211     SDValue Zero = DAG.getConstant(0, dl, VT);
1212     SDValue Ops[] = {One, Zero, TargetCC, Flag};
1213     return DAG.getNode(MSP430ISD::SELECT_CC, dl, Op.getValueType(), Ops);
1214   }
1215 }
1216 
1217 SDValue MSP430TargetLowering::LowerSELECT_CC(SDValue Op,
1218                                              SelectionDAG &DAG) const {
1219   SDValue LHS    = Op.getOperand(0);
1220   SDValue RHS    = Op.getOperand(1);
1221   SDValue TrueV  = Op.getOperand(2);
1222   SDValue FalseV = Op.getOperand(3);
1223   ISD::CondCode CC = cast<CondCodeSDNode>(Op.getOperand(4))->get();
1224   SDLoc dl   (Op);
1225 
1226   SDValue TargetCC;
1227   SDValue Flag = EmitCMP(LHS, RHS, TargetCC, CC, dl, DAG);
1228 
1229   SDValue Ops[] = {TrueV, FalseV, TargetCC, Flag};
1230 
1231   return DAG.getNode(MSP430ISD::SELECT_CC, dl, Op.getValueType(), Ops);
1232 }
1233 
1234 SDValue MSP430TargetLowering::LowerSIGN_EXTEND(SDValue Op,
1235                                                SelectionDAG &DAG) const {
1236   SDValue Val = Op.getOperand(0);
1237   EVT VT      = Op.getValueType();
1238   SDLoc dl(Op);
1239 
1240   assert(VT == MVT::i16 && "Only support i16 for now!");
1241 
1242   return DAG.getNode(ISD::SIGN_EXTEND_INREG, dl, VT,
1243                      DAG.getNode(ISD::ANY_EXTEND, dl, VT, Val),
1244                      DAG.getValueType(Val.getValueType()));
1245 }
1246 
1247 SDValue
1248 MSP430TargetLowering::getReturnAddressFrameIndex(SelectionDAG &DAG) const {
1249   MachineFunction &MF = DAG.getMachineFunction();
1250   MSP430MachineFunctionInfo *FuncInfo = MF.getInfo<MSP430MachineFunctionInfo>();
1251   int ReturnAddrIndex = FuncInfo->getRAIndex();
1252   MVT PtrVT = getFrameIndexTy(MF.getDataLayout());
1253 
1254   if (ReturnAddrIndex == 0) {
1255     // Set up a frame object for the return address.
1256     uint64_t SlotSize = PtrVT.getStoreSize();
1257     ReturnAddrIndex = MF.getFrameInfo().CreateFixedObject(SlotSize, -SlotSize,
1258                                                            true);
1259     FuncInfo->setRAIndex(ReturnAddrIndex);
1260   }
1261 
1262   return DAG.getFrameIndex(ReturnAddrIndex, PtrVT);
1263 }
1264 
1265 SDValue MSP430TargetLowering::LowerRETURNADDR(SDValue Op,
1266                                               SelectionDAG &DAG) const {
1267   MachineFrameInfo &MFI = DAG.getMachineFunction().getFrameInfo();
1268   MFI.setReturnAddressIsTaken(true);
1269 
1270   if (verifyReturnAddressArgumentIsConstant(Op, DAG))
1271     return SDValue();
1272 
1273   unsigned Depth = Op.getConstantOperandVal(0);
1274   SDLoc dl(Op);
1275   EVT PtrVT = Op.getValueType();
1276 
1277   if (Depth > 0) {
1278     SDValue FrameAddr = LowerFRAMEADDR(Op, DAG);
1279     SDValue Offset =
1280       DAG.getConstant(PtrVT.getStoreSize(), dl, MVT::i16);
1281     return DAG.getLoad(PtrVT, dl, DAG.getEntryNode(),
1282                        DAG.getNode(ISD::ADD, dl, PtrVT, FrameAddr, Offset),
1283                        MachinePointerInfo());
1284   }
1285 
1286   // Just load the return address.
1287   SDValue RetAddrFI = getReturnAddressFrameIndex(DAG);
1288   return DAG.getLoad(PtrVT, dl, DAG.getEntryNode(), RetAddrFI,
1289                      MachinePointerInfo());
1290 }
1291 
1292 SDValue MSP430TargetLowering::LowerFRAMEADDR(SDValue Op,
1293                                              SelectionDAG &DAG) const {
1294   MachineFrameInfo &MFI = DAG.getMachineFunction().getFrameInfo();
1295   MFI.setFrameAddressIsTaken(true);
1296 
1297   EVT VT = Op.getValueType();
1298   SDLoc dl(Op);  // FIXME probably not meaningful
1299   unsigned Depth = Op.getConstantOperandVal(0);
1300   SDValue FrameAddr = DAG.getCopyFromReg(DAG.getEntryNode(), dl,
1301                                          MSP430::R4, VT);
1302   while (Depth--)
1303     FrameAddr = DAG.getLoad(VT, dl, DAG.getEntryNode(), FrameAddr,
1304                             MachinePointerInfo());
1305   return FrameAddr;
1306 }
1307 
1308 SDValue MSP430TargetLowering::LowerVASTART(SDValue Op,
1309                                            SelectionDAG &DAG) const {
1310   MachineFunction &MF = DAG.getMachineFunction();
1311   MSP430MachineFunctionInfo *FuncInfo = MF.getInfo<MSP430MachineFunctionInfo>();
1312 
1313   SDValue Ptr = Op.getOperand(1);
1314   EVT PtrVT = Ptr.getValueType();
1315 
1316   // Frame index of first vararg argument
1317   SDValue FrameIndex =
1318       DAG.getFrameIndex(FuncInfo->getVarArgsFrameIndex(), PtrVT);
1319   const Value *SV = cast<SrcValueSDNode>(Op.getOperand(2))->getValue();
1320 
1321   // Create a store of the frame index to the location operand
1322   return DAG.getStore(Op.getOperand(0), SDLoc(Op), FrameIndex, Ptr,
1323                       MachinePointerInfo(SV));
1324 }
1325 
1326 SDValue MSP430TargetLowering::LowerJumpTable(SDValue Op,
1327                                              SelectionDAG &DAG) const {
1328     JumpTableSDNode *JT = cast<JumpTableSDNode>(Op);
1329     EVT PtrVT = Op.getValueType();
1330     SDValue Result = DAG.getTargetJumpTable(JT->getIndex(), PtrVT);
1331     return DAG.getNode(MSP430ISD::Wrapper, SDLoc(JT), PtrVT, Result);
1332 }
1333 
1334 /// getPostIndexedAddressParts - returns true by value, base pointer and
1335 /// offset pointer and addressing mode by reference if this node can be
1336 /// combined with a load / store to form a post-indexed load / store.
1337 bool MSP430TargetLowering::getPostIndexedAddressParts(SDNode *N, SDNode *Op,
1338                                                       SDValue &Base,
1339                                                       SDValue &Offset,
1340                                                       ISD::MemIndexedMode &AM,
1341                                                       SelectionDAG &DAG) const {
1342 
1343   LoadSDNode *LD = cast<LoadSDNode>(N);
1344   if (LD->getExtensionType() != ISD::NON_EXTLOAD)
1345     return false;
1346 
1347   EVT VT = LD->getMemoryVT();
1348   if (VT != MVT::i8 && VT != MVT::i16)
1349     return false;
1350 
1351   if (Op->getOpcode() != ISD::ADD)
1352     return false;
1353 
1354   if (ConstantSDNode *RHS = dyn_cast<ConstantSDNode>(Op->getOperand(1))) {
1355     uint64_t RHSC = RHS->getZExtValue();
1356     if ((VT == MVT::i16 && RHSC != 2) ||
1357         (VT == MVT::i8 && RHSC != 1))
1358       return false;
1359 
1360     Base = Op->getOperand(0);
1361     Offset = DAG.getConstant(RHSC, SDLoc(N), VT);
1362     AM = ISD::POST_INC;
1363     return true;
1364   }
1365 
1366   return false;
1367 }
1368 
1369 
1370 const char *MSP430TargetLowering::getTargetNodeName(unsigned Opcode) const {
1371   switch ((MSP430ISD::NodeType)Opcode) {
1372   case MSP430ISD::FIRST_NUMBER:       break;
1373   case MSP430ISD::RET_GLUE:           return "MSP430ISD::RET_GLUE";
1374   case MSP430ISD::RETI_GLUE:          return "MSP430ISD::RETI_GLUE";
1375   case MSP430ISD::RRA:                return "MSP430ISD::RRA";
1376   case MSP430ISD::RLA:                return "MSP430ISD::RLA";
1377   case MSP430ISD::RRC:                return "MSP430ISD::RRC";
1378   case MSP430ISD::RRCL:               return "MSP430ISD::RRCL";
1379   case MSP430ISD::CALL:               return "MSP430ISD::CALL";
1380   case MSP430ISD::Wrapper:            return "MSP430ISD::Wrapper";
1381   case MSP430ISD::BR_CC:              return "MSP430ISD::BR_CC";
1382   case MSP430ISD::CMP:                return "MSP430ISD::CMP";
1383   case MSP430ISD::SETCC:              return "MSP430ISD::SETCC";
1384   case MSP430ISD::SELECT_CC:          return "MSP430ISD::SELECT_CC";
1385   case MSP430ISD::DADD:               return "MSP430ISD::DADD";
1386   }
1387   return nullptr;
1388 }
1389 
1390 bool MSP430TargetLowering::isTruncateFree(Type *Ty1,
1391                                           Type *Ty2) const {
1392   if (!Ty1->isIntegerTy() || !Ty2->isIntegerTy())
1393     return false;
1394 
1395   return (Ty1->getPrimitiveSizeInBits().getFixedValue() >
1396           Ty2->getPrimitiveSizeInBits().getFixedValue());
1397 }
1398 
1399 bool MSP430TargetLowering::isTruncateFree(EVT VT1, EVT VT2) const {
1400   if (!VT1.isInteger() || !VT2.isInteger())
1401     return false;
1402 
1403   return (VT1.getFixedSizeInBits() > VT2.getFixedSizeInBits());
1404 }
1405 
1406 bool MSP430TargetLowering::isZExtFree(Type *Ty1, Type *Ty2) const {
1407   // MSP430 implicitly zero-extends 8-bit results in 16-bit registers.
1408   return false && Ty1->isIntegerTy(8) && Ty2->isIntegerTy(16);
1409 }
1410 
1411 bool MSP430TargetLowering::isZExtFree(EVT VT1, EVT VT2) const {
1412   // MSP430 implicitly zero-extends 8-bit results in 16-bit registers.
1413   return false && VT1 == MVT::i8 && VT2 == MVT::i16;
1414 }
1415 
1416 //===----------------------------------------------------------------------===//
1417 //  Other Lowering Code
1418 //===----------------------------------------------------------------------===//
1419 
1420 MachineBasicBlock *
1421 MSP430TargetLowering::EmitShiftInstr(MachineInstr &MI,
1422                                      MachineBasicBlock *BB) const {
1423   MachineFunction *F = BB->getParent();
1424   MachineRegisterInfo &RI = F->getRegInfo();
1425   DebugLoc dl = MI.getDebugLoc();
1426   const TargetInstrInfo &TII = *F->getSubtarget().getInstrInfo();
1427 
1428   unsigned Opc;
1429   bool ClearCarry = false;
1430   const TargetRegisterClass * RC;
1431   switch (MI.getOpcode()) {
1432   default: llvm_unreachable("Invalid shift opcode!");
1433   case MSP430::Shl8:
1434     Opc = MSP430::ADD8rr;
1435     RC = &MSP430::GR8RegClass;
1436     break;
1437   case MSP430::Shl16:
1438     Opc = MSP430::ADD16rr;
1439     RC = &MSP430::GR16RegClass;
1440     break;
1441   case MSP430::Sra8:
1442     Opc = MSP430::RRA8r;
1443     RC = &MSP430::GR8RegClass;
1444     break;
1445   case MSP430::Sra16:
1446     Opc = MSP430::RRA16r;
1447     RC = &MSP430::GR16RegClass;
1448     break;
1449   case MSP430::Srl8:
1450     ClearCarry = true;
1451     Opc = MSP430::RRC8r;
1452     RC = &MSP430::GR8RegClass;
1453     break;
1454   case MSP430::Srl16:
1455     ClearCarry = true;
1456     Opc = MSP430::RRC16r;
1457     RC = &MSP430::GR16RegClass;
1458     break;
1459   case MSP430::Rrcl8:
1460   case MSP430::Rrcl16: {
1461     BuildMI(*BB, MI, dl, TII.get(MSP430::BIC16rc), MSP430::SR)
1462       .addReg(MSP430::SR).addImm(1);
1463     Register SrcReg = MI.getOperand(1).getReg();
1464     Register DstReg = MI.getOperand(0).getReg();
1465     unsigned RrcOpc = MI.getOpcode() == MSP430::Rrcl16
1466                     ? MSP430::RRC16r : MSP430::RRC8r;
1467     BuildMI(*BB, MI, dl, TII.get(RrcOpc), DstReg)
1468       .addReg(SrcReg);
1469     MI.eraseFromParent(); // The pseudo instruction is gone now.
1470     return BB;
1471   }
1472   }
1473 
1474   const BasicBlock *LLVM_BB = BB->getBasicBlock();
1475   MachineFunction::iterator I = ++BB->getIterator();
1476 
1477   // Create loop block
1478   MachineBasicBlock *LoopBB = F->CreateMachineBasicBlock(LLVM_BB);
1479   MachineBasicBlock *RemBB  = F->CreateMachineBasicBlock(LLVM_BB);
1480 
1481   F->insert(I, LoopBB);
1482   F->insert(I, RemBB);
1483 
1484   // Update machine-CFG edges by transferring all successors of the current
1485   // block to the block containing instructions after shift.
1486   RemBB->splice(RemBB->begin(), BB, std::next(MachineBasicBlock::iterator(MI)),
1487                 BB->end());
1488   RemBB->transferSuccessorsAndUpdatePHIs(BB);
1489 
1490   // Add edges BB => LoopBB => RemBB, BB => RemBB, LoopBB => LoopBB
1491   BB->addSuccessor(LoopBB);
1492   BB->addSuccessor(RemBB);
1493   LoopBB->addSuccessor(RemBB);
1494   LoopBB->addSuccessor(LoopBB);
1495 
1496   Register ShiftAmtReg = RI.createVirtualRegister(&MSP430::GR8RegClass);
1497   Register ShiftAmtReg2 = RI.createVirtualRegister(&MSP430::GR8RegClass);
1498   Register ShiftReg = RI.createVirtualRegister(RC);
1499   Register ShiftReg2 = RI.createVirtualRegister(RC);
1500   Register ShiftAmtSrcReg = MI.getOperand(2).getReg();
1501   Register SrcReg = MI.getOperand(1).getReg();
1502   Register DstReg = MI.getOperand(0).getReg();
1503 
1504   // BB:
1505   // cmp 0, N
1506   // je RemBB
1507   BuildMI(BB, dl, TII.get(MSP430::CMP8ri))
1508     .addReg(ShiftAmtSrcReg).addImm(0);
1509   BuildMI(BB, dl, TII.get(MSP430::JCC))
1510     .addMBB(RemBB)
1511     .addImm(MSP430CC::COND_E);
1512 
1513   // LoopBB:
1514   // ShiftReg = phi [%SrcReg, BB], [%ShiftReg2, LoopBB]
1515   // ShiftAmt = phi [%N, BB],      [%ShiftAmt2, LoopBB]
1516   // ShiftReg2 = shift ShiftReg
1517   // ShiftAmt2 = ShiftAmt - 1;
1518   BuildMI(LoopBB, dl, TII.get(MSP430::PHI), ShiftReg)
1519     .addReg(SrcReg).addMBB(BB)
1520     .addReg(ShiftReg2).addMBB(LoopBB);
1521   BuildMI(LoopBB, dl, TII.get(MSP430::PHI), ShiftAmtReg)
1522     .addReg(ShiftAmtSrcReg).addMBB(BB)
1523     .addReg(ShiftAmtReg2).addMBB(LoopBB);
1524   if (ClearCarry)
1525     BuildMI(LoopBB, dl, TII.get(MSP430::BIC16rc), MSP430::SR)
1526       .addReg(MSP430::SR).addImm(1);
1527   if (Opc == MSP430::ADD8rr || Opc == MSP430::ADD16rr)
1528     BuildMI(LoopBB, dl, TII.get(Opc), ShiftReg2)
1529       .addReg(ShiftReg)
1530       .addReg(ShiftReg);
1531   else
1532     BuildMI(LoopBB, dl, TII.get(Opc), ShiftReg2)
1533       .addReg(ShiftReg);
1534   BuildMI(LoopBB, dl, TII.get(MSP430::SUB8ri), ShiftAmtReg2)
1535     .addReg(ShiftAmtReg).addImm(1);
1536   BuildMI(LoopBB, dl, TII.get(MSP430::JCC))
1537     .addMBB(LoopBB)
1538     .addImm(MSP430CC::COND_NE);
1539 
1540   // RemBB:
1541   // DestReg = phi [%SrcReg, BB], [%ShiftReg, LoopBB]
1542   BuildMI(*RemBB, RemBB->begin(), dl, TII.get(MSP430::PHI), DstReg)
1543     .addReg(SrcReg).addMBB(BB)
1544     .addReg(ShiftReg2).addMBB(LoopBB);
1545 
1546   MI.eraseFromParent(); // The pseudo instruction is gone now.
1547   return RemBB;
1548 }
1549 
1550 MachineBasicBlock *
1551 MSP430TargetLowering::EmitInstrWithCustomInserter(MachineInstr &MI,
1552                                                   MachineBasicBlock *BB) const {
1553   unsigned Opc = MI.getOpcode();
1554 
1555   if (Opc == MSP430::Shl8  || Opc == MSP430::Shl16 ||
1556       Opc == MSP430::Sra8  || Opc == MSP430::Sra16 ||
1557       Opc == MSP430::Srl8  || Opc == MSP430::Srl16 ||
1558       Opc == MSP430::Rrcl8 || Opc == MSP430::Rrcl16)
1559     return EmitShiftInstr(MI, BB);
1560 
1561   const TargetInstrInfo &TII = *BB->getParent()->getSubtarget().getInstrInfo();
1562   DebugLoc dl = MI.getDebugLoc();
1563 
1564   assert((Opc == MSP430::Select16 || Opc == MSP430::Select8) &&
1565          "Unexpected instr type to insert");
1566 
1567   // To "insert" a SELECT instruction, we actually have to insert the diamond
1568   // control-flow pattern.  The incoming instruction knows the destination vreg
1569   // to set, the condition code register to branch on, the true/false values to
1570   // select between, and a branch opcode to use.
1571   const BasicBlock *LLVM_BB = BB->getBasicBlock();
1572   MachineFunction::iterator I = ++BB->getIterator();
1573 
1574   //  thisMBB:
1575   //  ...
1576   //   TrueVal = ...
1577   //   cmpTY ccX, r1, r2
1578   //   jCC copy1MBB
1579   //   fallthrough --> copy0MBB
1580   MachineBasicBlock *thisMBB = BB;
1581   MachineFunction *F = BB->getParent();
1582   MachineBasicBlock *copy0MBB = F->CreateMachineBasicBlock(LLVM_BB);
1583   MachineBasicBlock *copy1MBB = F->CreateMachineBasicBlock(LLVM_BB);
1584   F->insert(I, copy0MBB);
1585   F->insert(I, copy1MBB);
1586   // Update machine-CFG edges by transferring all successors of the current
1587   // block to the new block which will contain the Phi node for the select.
1588   copy1MBB->splice(copy1MBB->begin(), BB,
1589                    std::next(MachineBasicBlock::iterator(MI)), BB->end());
1590   copy1MBB->transferSuccessorsAndUpdatePHIs(BB);
1591   // Next, add the true and fallthrough blocks as its successors.
1592   BB->addSuccessor(copy0MBB);
1593   BB->addSuccessor(copy1MBB);
1594 
1595   BuildMI(BB, dl, TII.get(MSP430::JCC))
1596       .addMBB(copy1MBB)
1597       .addImm(MI.getOperand(3).getImm());
1598 
1599   //  copy0MBB:
1600   //   %FalseValue = ...
1601   //   # fallthrough to copy1MBB
1602   BB = copy0MBB;
1603 
1604   // Update machine-CFG edges
1605   BB->addSuccessor(copy1MBB);
1606 
1607   //  copy1MBB:
1608   //   %Result = phi [ %FalseValue, copy0MBB ], [ %TrueValue, thisMBB ]
1609   //  ...
1610   BB = copy1MBB;
1611   BuildMI(*BB, BB->begin(), dl, TII.get(MSP430::PHI), MI.getOperand(0).getReg())
1612       .addReg(MI.getOperand(2).getReg())
1613       .addMBB(copy0MBB)
1614       .addReg(MI.getOperand(1).getReg())
1615       .addMBB(thisMBB);
1616 
1617   MI.eraseFromParent(); // The pseudo instruction is gone now.
1618   return BB;
1619 }
1620