xref: /freebsd/contrib/llvm-project/llvm/lib/Target/MSP430/MSP430ISelLowering.cpp (revision 18054d0220cfc8df9c9568c437bd6fbb59d53c3c)
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 }
337 
338 SDValue MSP430TargetLowering::LowerOperation(SDValue Op,
339                                              SelectionDAG &DAG) const {
340   switch (Op.getOpcode()) {
341   case ISD::SHL: // FALLTHROUGH
342   case ISD::SRL:
343   case ISD::SRA:              return LowerShifts(Op, DAG);
344   case ISD::GlobalAddress:    return LowerGlobalAddress(Op, DAG);
345   case ISD::BlockAddress:     return LowerBlockAddress(Op, DAG);
346   case ISD::ExternalSymbol:   return LowerExternalSymbol(Op, DAG);
347   case ISD::SETCC:            return LowerSETCC(Op, DAG);
348   case ISD::BR_CC:            return LowerBR_CC(Op, DAG);
349   case ISD::SELECT_CC:        return LowerSELECT_CC(Op, DAG);
350   case ISD::SIGN_EXTEND:      return LowerSIGN_EXTEND(Op, DAG);
351   case ISD::RETURNADDR:       return LowerRETURNADDR(Op, DAG);
352   case ISD::FRAMEADDR:        return LowerFRAMEADDR(Op, DAG);
353   case ISD::VASTART:          return LowerVASTART(Op, DAG);
354   case ISD::JumpTable:        return LowerJumpTable(Op, DAG);
355   default:
356     llvm_unreachable("unimplemented operand");
357   }
358 }
359 
360 // Define non profitable transforms into shifts
361 bool MSP430TargetLowering::shouldAvoidTransformToShift(EVT VT,
362                                                        unsigned Amount) const {
363   return !(Amount == 8 || Amount == 9 || Amount<=2);
364 }
365 
366 // Implemented to verify test case assertions in
367 // tests/codegen/msp430/shift-amount-threshold-b.ll
368 bool MSP430TargetLowering::isLegalICmpImmediate(int64_t Immed) const {
369   if (MSP430NoLegalImmediate)
370     return Immed >= -32 && Immed < 32;
371   return TargetLowering::isLegalICmpImmediate(Immed);
372 }
373 
374 //===----------------------------------------------------------------------===//
375 //                       MSP430 Inline Assembly Support
376 //===----------------------------------------------------------------------===//
377 
378 /// getConstraintType - Given a constraint letter, return the type of
379 /// constraint it is for this target.
380 TargetLowering::ConstraintType
381 MSP430TargetLowering::getConstraintType(StringRef Constraint) const {
382   if (Constraint.size() == 1) {
383     switch (Constraint[0]) {
384     case 'r':
385       return C_RegisterClass;
386     default:
387       break;
388     }
389   }
390   return TargetLowering::getConstraintType(Constraint);
391 }
392 
393 std::pair<unsigned, const TargetRegisterClass *>
394 MSP430TargetLowering::getRegForInlineAsmConstraint(
395     const TargetRegisterInfo *TRI, StringRef Constraint, MVT VT) const {
396   if (Constraint.size() == 1) {
397     // GCC Constraint Letters
398     switch (Constraint[0]) {
399     default: break;
400     case 'r':   // GENERAL_REGS
401       if (VT == MVT::i8)
402         return std::make_pair(0U, &MSP430::GR8RegClass);
403 
404       return std::make_pair(0U, &MSP430::GR16RegClass);
405     }
406   }
407 
408   return TargetLowering::getRegForInlineAsmConstraint(TRI, Constraint, VT);
409 }
410 
411 //===----------------------------------------------------------------------===//
412 //                      Calling Convention Implementation
413 //===----------------------------------------------------------------------===//
414 
415 #include "MSP430GenCallingConv.inc"
416 
417 /// For each argument in a function store the number of pieces it is composed
418 /// of.
419 template<typename ArgT>
420 static void ParseFunctionArgs(const SmallVectorImpl<ArgT> &Args,
421                               SmallVectorImpl<unsigned> &Out) {
422   unsigned CurrentArgIndex;
423 
424   if (Args.empty())
425     return;
426 
427   CurrentArgIndex = Args[0].OrigArgIndex;
428   Out.push_back(0);
429 
430   for (auto &Arg : Args) {
431     if (CurrentArgIndex == Arg.OrigArgIndex) {
432       Out.back() += 1;
433     } else {
434       Out.push_back(1);
435       CurrentArgIndex = Arg.OrigArgIndex;
436     }
437   }
438 }
439 
440 static void AnalyzeVarArgs(CCState &State,
441                            const SmallVectorImpl<ISD::OutputArg> &Outs) {
442   State.AnalyzeCallOperands(Outs, CC_MSP430_AssignStack);
443 }
444 
445 static void AnalyzeVarArgs(CCState &State,
446                            const SmallVectorImpl<ISD::InputArg> &Ins) {
447   State.AnalyzeFormalArguments(Ins, CC_MSP430_AssignStack);
448 }
449 
450 /// Analyze incoming and outgoing function arguments. We need custom C++ code
451 /// to handle special constraints in the ABI like reversing the order of the
452 /// pieces of splitted arguments. In addition, all pieces of a certain argument
453 /// have to be passed either using registers or the stack but never mixing both.
454 template<typename ArgT>
455 static void AnalyzeArguments(CCState &State,
456                              SmallVectorImpl<CCValAssign> &ArgLocs,
457                              const SmallVectorImpl<ArgT> &Args) {
458   static const MCPhysReg CRegList[] = {
459     MSP430::R12, MSP430::R13, MSP430::R14, MSP430::R15
460   };
461   static const unsigned CNbRegs = array_lengthof(CRegList);
462   static const MCPhysReg BuiltinRegList[] = {
463     MSP430::R8, MSP430::R9, MSP430::R10, MSP430::R11,
464     MSP430::R12, MSP430::R13, MSP430::R14, MSP430::R15
465   };
466   static const unsigned BuiltinNbRegs = array_lengthof(BuiltinRegList);
467 
468   ArrayRef<MCPhysReg> RegList;
469   unsigned NbRegs;
470 
471   bool Builtin = (State.getCallingConv() == CallingConv::MSP430_BUILTIN);
472   if (Builtin) {
473     RegList = BuiltinRegList;
474     NbRegs = BuiltinNbRegs;
475   } else {
476     RegList = CRegList;
477     NbRegs = CNbRegs;
478   }
479 
480   if (State.isVarArg()) {
481     AnalyzeVarArgs(State, Args);
482     return;
483   }
484 
485   SmallVector<unsigned, 4> ArgsParts;
486   ParseFunctionArgs(Args, ArgsParts);
487 
488   if (Builtin) {
489     assert(ArgsParts.size() == 2 &&
490         "Builtin calling convention requires two arguments");
491   }
492 
493   unsigned RegsLeft = NbRegs;
494   bool UsedStack = false;
495   unsigned ValNo = 0;
496 
497   for (unsigned i = 0, e = ArgsParts.size(); i != e; i++) {
498     MVT ArgVT = Args[ValNo].VT;
499     ISD::ArgFlagsTy ArgFlags = Args[ValNo].Flags;
500     MVT LocVT = ArgVT;
501     CCValAssign::LocInfo LocInfo = CCValAssign::Full;
502 
503     // Promote i8 to i16
504     if (LocVT == MVT::i8) {
505       LocVT = MVT::i16;
506       if (ArgFlags.isSExt())
507           LocInfo = CCValAssign::SExt;
508       else if (ArgFlags.isZExt())
509           LocInfo = CCValAssign::ZExt;
510       else
511           LocInfo = CCValAssign::AExt;
512     }
513 
514     // Handle byval arguments
515     if (ArgFlags.isByVal()) {
516       State.HandleByVal(ValNo++, ArgVT, LocVT, LocInfo, 2, Align(2), ArgFlags);
517       continue;
518     }
519 
520     unsigned Parts = ArgsParts[i];
521 
522     if (Builtin) {
523       assert(Parts == 4 &&
524           "Builtin calling convention requires 64-bit arguments");
525     }
526 
527     if (!UsedStack && Parts == 2 && RegsLeft == 1) {
528       // Special case for 32-bit register split, see EABI section 3.3.3
529       unsigned Reg = State.AllocateReg(RegList);
530       State.addLoc(CCValAssign::getReg(ValNo++, ArgVT, Reg, LocVT, LocInfo));
531       RegsLeft -= 1;
532 
533       UsedStack = true;
534       CC_MSP430_AssignStack(ValNo++, ArgVT, LocVT, LocInfo, ArgFlags, State);
535     } else if (Parts <= RegsLeft) {
536       for (unsigned j = 0; j < Parts; j++) {
537         unsigned Reg = State.AllocateReg(RegList);
538         State.addLoc(CCValAssign::getReg(ValNo++, ArgVT, Reg, LocVT, LocInfo));
539         RegsLeft--;
540       }
541     } else {
542       UsedStack = true;
543       for (unsigned j = 0; j < Parts; j++)
544         CC_MSP430_AssignStack(ValNo++, ArgVT, LocVT, LocInfo, ArgFlags, State);
545     }
546   }
547 }
548 
549 static void AnalyzeRetResult(CCState &State,
550                              const SmallVectorImpl<ISD::InputArg> &Ins) {
551   State.AnalyzeCallResult(Ins, RetCC_MSP430);
552 }
553 
554 static void AnalyzeRetResult(CCState &State,
555                              const SmallVectorImpl<ISD::OutputArg> &Outs) {
556   State.AnalyzeReturn(Outs, RetCC_MSP430);
557 }
558 
559 template<typename ArgT>
560 static void AnalyzeReturnValues(CCState &State,
561                                 SmallVectorImpl<CCValAssign> &RVLocs,
562                                 const SmallVectorImpl<ArgT> &Args) {
563   AnalyzeRetResult(State, Args);
564 }
565 
566 SDValue MSP430TargetLowering::LowerFormalArguments(
567     SDValue Chain, CallingConv::ID CallConv, bool isVarArg,
568     const SmallVectorImpl<ISD::InputArg> &Ins, const SDLoc &dl,
569     SelectionDAG &DAG, SmallVectorImpl<SDValue> &InVals) const {
570 
571   switch (CallConv) {
572   default:
573     report_fatal_error("Unsupported calling convention");
574   case CallingConv::C:
575   case CallingConv::Fast:
576     return LowerCCCArguments(Chain, CallConv, isVarArg, Ins, dl, DAG, InVals);
577   case CallingConv::MSP430_INTR:
578     if (Ins.empty())
579       return Chain;
580     report_fatal_error("ISRs cannot have arguments");
581   }
582 }
583 
584 SDValue
585 MSP430TargetLowering::LowerCall(TargetLowering::CallLoweringInfo &CLI,
586                                 SmallVectorImpl<SDValue> &InVals) const {
587   SelectionDAG &DAG                     = CLI.DAG;
588   SDLoc &dl                             = CLI.DL;
589   SmallVectorImpl<ISD::OutputArg> &Outs = CLI.Outs;
590   SmallVectorImpl<SDValue> &OutVals     = CLI.OutVals;
591   SmallVectorImpl<ISD::InputArg> &Ins   = CLI.Ins;
592   SDValue Chain                         = CLI.Chain;
593   SDValue Callee                        = CLI.Callee;
594   bool &isTailCall                      = CLI.IsTailCall;
595   CallingConv::ID CallConv              = CLI.CallConv;
596   bool isVarArg                         = CLI.IsVarArg;
597 
598   // MSP430 target does not yet support tail call optimization.
599   isTailCall = false;
600 
601   switch (CallConv) {
602   default:
603     report_fatal_error("Unsupported calling convention");
604   case CallingConv::MSP430_BUILTIN:
605   case CallingConv::Fast:
606   case CallingConv::C:
607     return LowerCCCCallTo(Chain, Callee, CallConv, isVarArg, isTailCall,
608                           Outs, OutVals, Ins, dl, DAG, InVals);
609   case CallingConv::MSP430_INTR:
610     report_fatal_error("ISRs cannot be called directly");
611   }
612 }
613 
614 /// LowerCCCArguments - transform physical registers into virtual registers and
615 /// generate load operations for arguments places on the stack.
616 // FIXME: struct return stuff
617 SDValue MSP430TargetLowering::LowerCCCArguments(
618     SDValue Chain, CallingConv::ID CallConv, bool isVarArg,
619     const SmallVectorImpl<ISD::InputArg> &Ins, const SDLoc &dl,
620     SelectionDAG &DAG, SmallVectorImpl<SDValue> &InVals) const {
621   MachineFunction &MF = DAG.getMachineFunction();
622   MachineFrameInfo &MFI = MF.getFrameInfo();
623   MachineRegisterInfo &RegInfo = MF.getRegInfo();
624   MSP430MachineFunctionInfo *FuncInfo = MF.getInfo<MSP430MachineFunctionInfo>();
625 
626   // Assign locations to all of the incoming arguments.
627   SmallVector<CCValAssign, 16> ArgLocs;
628   CCState CCInfo(CallConv, isVarArg, DAG.getMachineFunction(), ArgLocs,
629                  *DAG.getContext());
630   AnalyzeArguments(CCInfo, ArgLocs, Ins);
631 
632   // Create frame index for the start of the first vararg value
633   if (isVarArg) {
634     unsigned Offset = CCInfo.getNextStackOffset();
635     FuncInfo->setVarArgsFrameIndex(MFI.CreateFixedObject(1, Offset, true));
636   }
637 
638   for (unsigned i = 0, e = ArgLocs.size(); i != e; ++i) {
639     CCValAssign &VA = ArgLocs[i];
640     if (VA.isRegLoc()) {
641       // Arguments passed in registers
642       EVT RegVT = VA.getLocVT();
643       switch (RegVT.getSimpleVT().SimpleTy) {
644       default:
645         {
646 #ifndef NDEBUG
647           errs() << "LowerFormalArguments Unhandled argument type: "
648                << RegVT.getEVTString() << "\n";
649 #endif
650           llvm_unreachable(nullptr);
651         }
652       case MVT::i16:
653         Register VReg = RegInfo.createVirtualRegister(&MSP430::GR16RegClass);
654         RegInfo.addLiveIn(VA.getLocReg(), VReg);
655         SDValue ArgValue = DAG.getCopyFromReg(Chain, dl, VReg, RegVT);
656 
657         // If this is an 8-bit value, it is really passed promoted to 16
658         // bits. Insert an assert[sz]ext to capture this, then truncate to the
659         // right size.
660         if (VA.getLocInfo() == CCValAssign::SExt)
661           ArgValue = DAG.getNode(ISD::AssertSext, dl, RegVT, ArgValue,
662                                  DAG.getValueType(VA.getValVT()));
663         else if (VA.getLocInfo() == CCValAssign::ZExt)
664           ArgValue = DAG.getNode(ISD::AssertZext, dl, RegVT, ArgValue,
665                                  DAG.getValueType(VA.getValVT()));
666 
667         if (VA.getLocInfo() != CCValAssign::Full)
668           ArgValue = DAG.getNode(ISD::TRUNCATE, dl, VA.getValVT(), ArgValue);
669 
670         InVals.push_back(ArgValue);
671       }
672     } else {
673       // Only arguments passed on the stack should make it here.
674       assert(VA.isMemLoc());
675 
676       SDValue InVal;
677       ISD::ArgFlagsTy Flags = Ins[i].Flags;
678 
679       if (Flags.isByVal()) {
680         int FI = MFI.CreateFixedObject(Flags.getByValSize(),
681                                        VA.getLocMemOffset(), true);
682         InVal = DAG.getFrameIndex(FI, getPointerTy(DAG.getDataLayout()));
683       } else {
684         // Load the argument to a virtual register
685         unsigned ObjSize = VA.getLocVT().getSizeInBits()/8;
686         if (ObjSize > 2) {
687             errs() << "LowerFormalArguments Unhandled argument type: "
688                 << EVT(VA.getLocVT()).getEVTString()
689                 << "\n";
690         }
691         // Create the frame index object for this incoming parameter...
692         int FI = MFI.CreateFixedObject(ObjSize, VA.getLocMemOffset(), true);
693 
694         // Create the SelectionDAG nodes corresponding to a load
695         //from this parameter
696         SDValue FIN = DAG.getFrameIndex(FI, MVT::i16);
697         InVal = DAG.getLoad(
698             VA.getLocVT(), dl, Chain, FIN,
699             MachinePointerInfo::getFixedStack(DAG.getMachineFunction(), FI));
700       }
701 
702       InVals.push_back(InVal);
703     }
704   }
705 
706   for (unsigned i = 0, e = ArgLocs.size(); i != e; ++i) {
707     if (Ins[i].Flags.isSRet()) {
708       Register Reg = FuncInfo->getSRetReturnReg();
709       if (!Reg) {
710         Reg = MF.getRegInfo().createVirtualRegister(
711             getRegClassFor(MVT::i16));
712         FuncInfo->setSRetReturnReg(Reg);
713       }
714       SDValue Copy = DAG.getCopyToReg(DAG.getEntryNode(), dl, Reg, InVals[i]);
715       Chain = DAG.getNode(ISD::TokenFactor, dl, MVT::Other, Copy, Chain);
716     }
717   }
718 
719   return Chain;
720 }
721 
722 bool
723 MSP430TargetLowering::CanLowerReturn(CallingConv::ID CallConv,
724                                      MachineFunction &MF,
725                                      bool IsVarArg,
726                                      const SmallVectorImpl<ISD::OutputArg> &Outs,
727                                      LLVMContext &Context) const {
728   SmallVector<CCValAssign, 16> RVLocs;
729   CCState CCInfo(CallConv, IsVarArg, MF, RVLocs, Context);
730   return CCInfo.CheckReturn(Outs, RetCC_MSP430);
731 }
732 
733 SDValue
734 MSP430TargetLowering::LowerReturn(SDValue Chain, CallingConv::ID CallConv,
735                                   bool isVarArg,
736                                   const SmallVectorImpl<ISD::OutputArg> &Outs,
737                                   const SmallVectorImpl<SDValue> &OutVals,
738                                   const SDLoc &dl, SelectionDAG &DAG) const {
739 
740   MachineFunction &MF = DAG.getMachineFunction();
741 
742   // CCValAssign - represent the assignment of the return value to a location
743   SmallVector<CCValAssign, 16> RVLocs;
744 
745   // ISRs cannot return any value.
746   if (CallConv == CallingConv::MSP430_INTR && !Outs.empty())
747     report_fatal_error("ISRs cannot return any value");
748 
749   // CCState - Info about the registers and stack slot.
750   CCState CCInfo(CallConv, isVarArg, DAG.getMachineFunction(), RVLocs,
751                  *DAG.getContext());
752 
753   // Analize return values.
754   AnalyzeReturnValues(CCInfo, RVLocs, Outs);
755 
756   SDValue Flag;
757   SmallVector<SDValue, 4> RetOps(1, Chain);
758 
759   // Copy the result values into the output registers.
760   for (unsigned i = 0; i != RVLocs.size(); ++i) {
761     CCValAssign &VA = RVLocs[i];
762     assert(VA.isRegLoc() && "Can only return in registers!");
763 
764     Chain = DAG.getCopyToReg(Chain, dl, VA.getLocReg(),
765                              OutVals[i], Flag);
766 
767     // Guarantee that all emitted copies are stuck together,
768     // avoiding something bad.
769     Flag = Chain.getValue(1);
770     RetOps.push_back(DAG.getRegister(VA.getLocReg(), VA.getLocVT()));
771   }
772 
773   if (MF.getFunction().hasStructRetAttr()) {
774     MSP430MachineFunctionInfo *FuncInfo = MF.getInfo<MSP430MachineFunctionInfo>();
775     Register Reg = FuncInfo->getSRetReturnReg();
776 
777     if (!Reg)
778       llvm_unreachable("sret virtual register not created in entry block");
779 
780     SDValue Val =
781       DAG.getCopyFromReg(Chain, dl, Reg, getPointerTy(DAG.getDataLayout()));
782     unsigned R12 = MSP430::R12;
783 
784     Chain = DAG.getCopyToReg(Chain, dl, R12, Val, Flag);
785     Flag = Chain.getValue(1);
786     RetOps.push_back(DAG.getRegister(R12, getPointerTy(DAG.getDataLayout())));
787   }
788 
789   unsigned Opc = (CallConv == CallingConv::MSP430_INTR ?
790                   MSP430ISD::RETI_FLAG : MSP430ISD::RET_FLAG);
791 
792   RetOps[0] = Chain;  // Update chain.
793 
794   // Add the flag if we have it.
795   if (Flag.getNode())
796     RetOps.push_back(Flag);
797 
798   return DAG.getNode(Opc, dl, MVT::Other, RetOps);
799 }
800 
801 /// LowerCCCCallTo - functions arguments are copied from virtual regs to
802 /// (physical regs)/(stack frame), CALLSEQ_START and CALLSEQ_END are emitted.
803 SDValue MSP430TargetLowering::LowerCCCCallTo(
804     SDValue Chain, SDValue Callee, CallingConv::ID CallConv, bool isVarArg,
805     bool isTailCall, const SmallVectorImpl<ISD::OutputArg> &Outs,
806     const SmallVectorImpl<SDValue> &OutVals,
807     const SmallVectorImpl<ISD::InputArg> &Ins, const SDLoc &dl,
808     SelectionDAG &DAG, SmallVectorImpl<SDValue> &InVals) const {
809   // Analyze operands of the call, assigning locations to each operand.
810   SmallVector<CCValAssign, 16> ArgLocs;
811   CCState CCInfo(CallConv, isVarArg, DAG.getMachineFunction(), ArgLocs,
812                  *DAG.getContext());
813   AnalyzeArguments(CCInfo, ArgLocs, Outs);
814 
815   // Get a count of how many bytes are to be pushed on the stack.
816   unsigned NumBytes = CCInfo.getNextStackOffset();
817   auto PtrVT = getPointerTy(DAG.getDataLayout());
818 
819   Chain = DAG.getCALLSEQ_START(Chain, NumBytes, 0, dl);
820 
821   SmallVector<std::pair<unsigned, SDValue>, 4> RegsToPass;
822   SmallVector<SDValue, 12> MemOpChains;
823   SDValue StackPtr;
824 
825   // Walk the register/memloc assignments, inserting copies/loads.
826   for (unsigned i = 0, e = ArgLocs.size(); i != e; ++i) {
827     CCValAssign &VA = ArgLocs[i];
828 
829     SDValue Arg = OutVals[i];
830 
831     // Promote the value if needed.
832     switch (VA.getLocInfo()) {
833       default: llvm_unreachable("Unknown loc info!");
834       case CCValAssign::Full: break;
835       case CCValAssign::SExt:
836         Arg = DAG.getNode(ISD::SIGN_EXTEND, dl, VA.getLocVT(), Arg);
837         break;
838       case CCValAssign::ZExt:
839         Arg = DAG.getNode(ISD::ZERO_EXTEND, dl, VA.getLocVT(), Arg);
840         break;
841       case CCValAssign::AExt:
842         Arg = DAG.getNode(ISD::ANY_EXTEND, dl, VA.getLocVT(), Arg);
843         break;
844     }
845 
846     // Arguments that can be passed on register must be kept at RegsToPass
847     // vector
848     if (VA.isRegLoc()) {
849       RegsToPass.push_back(std::make_pair(VA.getLocReg(), Arg));
850     } else {
851       assert(VA.isMemLoc());
852 
853       if (!StackPtr.getNode())
854         StackPtr = DAG.getCopyFromReg(Chain, dl, MSP430::SP, PtrVT);
855 
856       SDValue PtrOff =
857           DAG.getNode(ISD::ADD, dl, PtrVT, StackPtr,
858                       DAG.getIntPtrConstant(VA.getLocMemOffset(), dl));
859 
860       SDValue MemOp;
861       ISD::ArgFlagsTy Flags = Outs[i].Flags;
862 
863       if (Flags.isByVal()) {
864         SDValue SizeNode = DAG.getConstant(Flags.getByValSize(), dl, MVT::i16);
865         MemOp = DAG.getMemcpy(
866             Chain, dl, PtrOff, Arg, SizeNode, Flags.getNonZeroByValAlign(),
867             /*isVolatile*/ false,
868             /*AlwaysInline=*/true,
869             /*isTailCall=*/false, MachinePointerInfo(), MachinePointerInfo());
870       } else {
871         MemOp = DAG.getStore(Chain, dl, Arg, PtrOff, MachinePointerInfo());
872       }
873 
874       MemOpChains.push_back(MemOp);
875     }
876   }
877 
878   // Transform all store nodes into one single node because all store nodes are
879   // independent of each other.
880   if (!MemOpChains.empty())
881     Chain = DAG.getNode(ISD::TokenFactor, dl, MVT::Other, MemOpChains);
882 
883   // Build a sequence of copy-to-reg nodes chained together with token chain and
884   // flag operands which copy the outgoing args into registers.  The InFlag in
885   // necessary since all emitted instructions must be stuck together.
886   SDValue InFlag;
887   for (unsigned i = 0, e = RegsToPass.size(); i != e; ++i) {
888     Chain = DAG.getCopyToReg(Chain, dl, RegsToPass[i].first,
889                              RegsToPass[i].second, InFlag);
890     InFlag = Chain.getValue(1);
891   }
892 
893   // If the callee is a GlobalAddress node (quite common, every direct call is)
894   // turn it into a TargetGlobalAddress node so that legalize doesn't hack it.
895   // Likewise ExternalSymbol -> TargetExternalSymbol.
896   if (GlobalAddressSDNode *G = dyn_cast<GlobalAddressSDNode>(Callee))
897     Callee = DAG.getTargetGlobalAddress(G->getGlobal(), dl, MVT::i16);
898   else if (ExternalSymbolSDNode *E = dyn_cast<ExternalSymbolSDNode>(Callee))
899     Callee = DAG.getTargetExternalSymbol(E->getSymbol(), MVT::i16);
900 
901   // Returns a chain & a flag for retval copy to use.
902   SDVTList NodeTys = DAG.getVTList(MVT::Other, MVT::Glue);
903   SmallVector<SDValue, 8> Ops;
904   Ops.push_back(Chain);
905   Ops.push_back(Callee);
906 
907   // Add argument registers to the end of the list so that they are
908   // known live into the call.
909   for (unsigned i = 0, e = RegsToPass.size(); i != e; ++i)
910     Ops.push_back(DAG.getRegister(RegsToPass[i].first,
911                                   RegsToPass[i].second.getValueType()));
912 
913   if (InFlag.getNode())
914     Ops.push_back(InFlag);
915 
916   Chain = DAG.getNode(MSP430ISD::CALL, dl, NodeTys, Ops);
917   InFlag = Chain.getValue(1);
918 
919   // Create the CALLSEQ_END node.
920   Chain = DAG.getCALLSEQ_END(Chain, DAG.getConstant(NumBytes, dl, PtrVT, true),
921                              DAG.getConstant(0, dl, PtrVT, true), InFlag, dl);
922   InFlag = Chain.getValue(1);
923 
924   // Handle result values, copying them out of physregs into vregs that we
925   // return.
926   return LowerCallResult(Chain, InFlag, CallConv, isVarArg, Ins, dl,
927                          DAG, InVals);
928 }
929 
930 /// LowerCallResult - Lower the result values of a call into the
931 /// appropriate copies out of appropriate physical registers.
932 ///
933 SDValue MSP430TargetLowering::LowerCallResult(
934     SDValue Chain, SDValue InFlag, CallingConv::ID CallConv, bool isVarArg,
935     const SmallVectorImpl<ISD::InputArg> &Ins, const SDLoc &dl,
936     SelectionDAG &DAG, SmallVectorImpl<SDValue> &InVals) const {
937 
938   // Assign locations to each value returned by this call.
939   SmallVector<CCValAssign, 16> RVLocs;
940   CCState CCInfo(CallConv, isVarArg, DAG.getMachineFunction(), RVLocs,
941                  *DAG.getContext());
942 
943   AnalyzeReturnValues(CCInfo, RVLocs, Ins);
944 
945   // Copy all of the result registers out of their specified physreg.
946   for (unsigned i = 0; i != RVLocs.size(); ++i) {
947     Chain = DAG.getCopyFromReg(Chain, dl, RVLocs[i].getLocReg(),
948                                RVLocs[i].getValVT(), InFlag).getValue(1);
949     InFlag = Chain.getValue(2);
950     InVals.push_back(Chain.getValue(0));
951   }
952 
953   return Chain;
954 }
955 
956 SDValue MSP430TargetLowering::LowerShifts(SDValue Op,
957                                           SelectionDAG &DAG) const {
958   unsigned Opc = Op.getOpcode();
959   SDNode* N = Op.getNode();
960   EVT VT = Op.getValueType();
961   SDLoc dl(N);
962 
963   // Expand non-constant shifts to loops:
964   if (!isa<ConstantSDNode>(N->getOperand(1)))
965     return Op;
966 
967   uint64_t ShiftAmount = cast<ConstantSDNode>(N->getOperand(1))->getZExtValue();
968 
969   // Expand the stuff into sequence of shifts.
970   SDValue Victim = N->getOperand(0);
971 
972   if (ShiftAmount >= 8) {
973     assert(VT == MVT::i16 && "Can not shift i8 by 8 and more");
974     switch(Opc) {
975     default:
976       llvm_unreachable("Unknown shift");
977     case ISD::SHL:
978       // foo << (8 + N) => swpb(zext(foo)) << N
979       Victim = DAG.getZeroExtendInReg(Victim, dl, MVT::i8);
980       Victim = DAG.getNode(ISD::BSWAP, dl, VT, Victim);
981       break;
982     case ISD::SRA:
983     case ISD::SRL:
984       // foo >> (8 + N) => sxt(swpb(foo)) >> N
985       Victim = DAG.getNode(ISD::BSWAP, dl, VT, Victim);
986       Victim = (Opc == ISD::SRA)
987                    ? DAG.getNode(ISD::SIGN_EXTEND_INREG, dl, VT, Victim,
988                                  DAG.getValueType(MVT::i8))
989                    : DAG.getZeroExtendInReg(Victim, dl, MVT::i8);
990       break;
991     }
992     ShiftAmount -= 8;
993   }
994 
995   if (Opc == ISD::SRL && ShiftAmount) {
996     // Emit a special goodness here:
997     // srl A, 1 => clrc; rrc A
998     Victim = DAG.getNode(MSP430ISD::RRCL, dl, VT, Victim);
999     ShiftAmount -= 1;
1000   }
1001 
1002   while (ShiftAmount--)
1003     Victim = DAG.getNode((Opc == ISD::SHL ? MSP430ISD::RLA : MSP430ISD::RRA),
1004                          dl, VT, Victim);
1005 
1006   return Victim;
1007 }
1008 
1009 SDValue MSP430TargetLowering::LowerGlobalAddress(SDValue Op,
1010                                                  SelectionDAG &DAG) const {
1011   const GlobalValue *GV = cast<GlobalAddressSDNode>(Op)->getGlobal();
1012   int64_t Offset = cast<GlobalAddressSDNode>(Op)->getOffset();
1013   auto PtrVT = getPointerTy(DAG.getDataLayout());
1014 
1015   // Create the TargetGlobalAddress node, folding in the constant offset.
1016   SDValue Result = DAG.getTargetGlobalAddress(GV, SDLoc(Op), PtrVT, Offset);
1017   return DAG.getNode(MSP430ISD::Wrapper, SDLoc(Op), PtrVT, Result);
1018 }
1019 
1020 SDValue MSP430TargetLowering::LowerExternalSymbol(SDValue Op,
1021                                                   SelectionDAG &DAG) const {
1022   SDLoc dl(Op);
1023   const char *Sym = cast<ExternalSymbolSDNode>(Op)->getSymbol();
1024   auto PtrVT = getPointerTy(DAG.getDataLayout());
1025   SDValue Result = DAG.getTargetExternalSymbol(Sym, PtrVT);
1026 
1027   return DAG.getNode(MSP430ISD::Wrapper, dl, PtrVT, Result);
1028 }
1029 
1030 SDValue MSP430TargetLowering::LowerBlockAddress(SDValue Op,
1031                                                 SelectionDAG &DAG) const {
1032   SDLoc dl(Op);
1033   auto PtrVT = getPointerTy(DAG.getDataLayout());
1034   const BlockAddress *BA = cast<BlockAddressSDNode>(Op)->getBlockAddress();
1035   SDValue Result = DAG.getTargetBlockAddress(BA, PtrVT);
1036 
1037   return DAG.getNode(MSP430ISD::Wrapper, dl, PtrVT, Result);
1038 }
1039 
1040 static SDValue EmitCMP(SDValue &LHS, SDValue &RHS, SDValue &TargetCC,
1041                        ISD::CondCode CC, const SDLoc &dl, SelectionDAG &DAG) {
1042   // FIXME: Handle bittests someday
1043   assert(!LHS.getValueType().isFloatingPoint() && "We don't handle FP yet");
1044 
1045   // FIXME: Handle jump negative someday
1046   MSP430CC::CondCodes TCC = MSP430CC::COND_INVALID;
1047   switch (CC) {
1048   default: llvm_unreachable("Invalid integer condition!");
1049   case ISD::SETEQ:
1050     TCC = MSP430CC::COND_E;     // aka COND_Z
1051     // Minor optimization: if LHS is a constant, swap operands, then the
1052     // constant can be folded into comparison.
1053     if (LHS.getOpcode() == ISD::Constant)
1054       std::swap(LHS, RHS);
1055     break;
1056   case ISD::SETNE:
1057     TCC = MSP430CC::COND_NE;    // aka COND_NZ
1058     // Minor optimization: if LHS is a constant, swap operands, then the
1059     // constant can be folded into comparison.
1060     if (LHS.getOpcode() == ISD::Constant)
1061       std::swap(LHS, RHS);
1062     break;
1063   case ISD::SETULE:
1064     std::swap(LHS, RHS);
1065     LLVM_FALLTHROUGH;
1066   case ISD::SETUGE:
1067     // Turn lhs u>= rhs with lhs constant into rhs u< lhs+1, this allows us to
1068     // fold constant into instruction.
1069     if (const ConstantSDNode * C = dyn_cast<ConstantSDNode>(LHS)) {
1070       LHS = RHS;
1071       RHS = DAG.getConstant(C->getSExtValue() + 1, dl, C->getValueType(0));
1072       TCC = MSP430CC::COND_LO;
1073       break;
1074     }
1075     TCC = MSP430CC::COND_HS;    // aka COND_C
1076     break;
1077   case ISD::SETUGT:
1078     std::swap(LHS, RHS);
1079     LLVM_FALLTHROUGH;
1080   case ISD::SETULT:
1081     // Turn lhs u< rhs with lhs constant into rhs u>= lhs+1, this allows us to
1082     // fold constant into instruction.
1083     if (const ConstantSDNode * C = dyn_cast<ConstantSDNode>(LHS)) {
1084       LHS = RHS;
1085       RHS = DAG.getConstant(C->getSExtValue() + 1, dl, C->getValueType(0));
1086       TCC = MSP430CC::COND_HS;
1087       break;
1088     }
1089     TCC = MSP430CC::COND_LO;    // aka COND_NC
1090     break;
1091   case ISD::SETLE:
1092     std::swap(LHS, RHS);
1093     LLVM_FALLTHROUGH;
1094   case ISD::SETGE:
1095     // Turn lhs >= rhs with lhs constant into rhs < lhs+1, this allows us to
1096     // fold constant into instruction.
1097     if (const ConstantSDNode * C = dyn_cast<ConstantSDNode>(LHS)) {
1098       LHS = RHS;
1099       RHS = DAG.getConstant(C->getSExtValue() + 1, dl, C->getValueType(0));
1100       TCC = MSP430CC::COND_L;
1101       break;
1102     }
1103     TCC = MSP430CC::COND_GE;
1104     break;
1105   case ISD::SETGT:
1106     std::swap(LHS, RHS);
1107     LLVM_FALLTHROUGH;
1108   case ISD::SETLT:
1109     // Turn lhs < rhs with lhs constant into rhs >= lhs+1, this allows us to
1110     // fold constant into instruction.
1111     if (const ConstantSDNode * C = dyn_cast<ConstantSDNode>(LHS)) {
1112       LHS = RHS;
1113       RHS = DAG.getConstant(C->getSExtValue() + 1, dl, C->getValueType(0));
1114       TCC = MSP430CC::COND_GE;
1115       break;
1116     }
1117     TCC = MSP430CC::COND_L;
1118     break;
1119   }
1120 
1121   TargetCC = DAG.getConstant(TCC, dl, MVT::i8);
1122   return DAG.getNode(MSP430ISD::CMP, dl, MVT::Glue, LHS, RHS);
1123 }
1124 
1125 
1126 SDValue MSP430TargetLowering::LowerBR_CC(SDValue Op, SelectionDAG &DAG) const {
1127   SDValue Chain = Op.getOperand(0);
1128   ISD::CondCode CC = cast<CondCodeSDNode>(Op.getOperand(1))->get();
1129   SDValue LHS   = Op.getOperand(2);
1130   SDValue RHS   = Op.getOperand(3);
1131   SDValue Dest  = Op.getOperand(4);
1132   SDLoc dl  (Op);
1133 
1134   SDValue TargetCC;
1135   SDValue Flag = EmitCMP(LHS, RHS, TargetCC, CC, dl, DAG);
1136 
1137   return DAG.getNode(MSP430ISD::BR_CC, dl, Op.getValueType(),
1138                      Chain, Dest, TargetCC, Flag);
1139 }
1140 
1141 SDValue MSP430TargetLowering::LowerSETCC(SDValue Op, SelectionDAG &DAG) const {
1142   SDValue LHS   = Op.getOperand(0);
1143   SDValue RHS   = Op.getOperand(1);
1144   SDLoc dl  (Op);
1145 
1146   // If we are doing an AND and testing against zero, then the CMP
1147   // will not be generated.  The AND (or BIT) will generate the condition codes,
1148   // but they are different from CMP.
1149   // FIXME: since we're doing a post-processing, use a pseudoinstr here, so
1150   // lowering & isel wouldn't diverge.
1151   bool andCC = false;
1152   if (ConstantSDNode *RHSC = dyn_cast<ConstantSDNode>(RHS)) {
1153     if (RHSC->isZero() && LHS.hasOneUse() &&
1154         (LHS.getOpcode() == ISD::AND ||
1155          (LHS.getOpcode() == ISD::TRUNCATE &&
1156           LHS.getOperand(0).getOpcode() == ISD::AND))) {
1157       andCC = true;
1158     }
1159   }
1160   ISD::CondCode CC = cast<CondCodeSDNode>(Op.getOperand(2))->get();
1161   SDValue TargetCC;
1162   SDValue Flag = EmitCMP(LHS, RHS, TargetCC, CC, dl, DAG);
1163 
1164   // Get the condition codes directly from the status register, if its easy.
1165   // Otherwise a branch will be generated.  Note that the AND and BIT
1166   // instructions generate different flags than CMP, the carry bit can be used
1167   // for NE/EQ.
1168   bool Invert = false;
1169   bool Shift = false;
1170   bool Convert = true;
1171   switch (cast<ConstantSDNode>(TargetCC)->getZExtValue()) {
1172    default:
1173     Convert = false;
1174     break;
1175    case MSP430CC::COND_HS:
1176      // Res = SR & 1, no processing is required
1177      break;
1178    case MSP430CC::COND_LO:
1179      // Res = ~(SR & 1)
1180      Invert = true;
1181      break;
1182    case MSP430CC::COND_NE:
1183      if (andCC) {
1184        // C = ~Z, thus Res = SR & 1, no processing is required
1185      } else {
1186        // Res = ~((SR >> 1) & 1)
1187        Shift = true;
1188        Invert = true;
1189      }
1190      break;
1191    case MSP430CC::COND_E:
1192      Shift = true;
1193      // C = ~Z for AND instruction, thus we can put Res = ~(SR & 1), however,
1194      // Res = (SR >> 1) & 1 is 1 word shorter.
1195      break;
1196   }
1197   EVT VT = Op.getValueType();
1198   SDValue One  = DAG.getConstant(1, dl, VT);
1199   if (Convert) {
1200     SDValue SR = DAG.getCopyFromReg(DAG.getEntryNode(), dl, MSP430::SR,
1201                                     MVT::i16, Flag);
1202     if (Shift)
1203       // FIXME: somewhere this is turned into a SRL, lower it MSP specific?
1204       SR = DAG.getNode(ISD::SRA, dl, MVT::i16, SR, One);
1205     SR = DAG.getNode(ISD::AND, dl, MVT::i16, SR, One);
1206     if (Invert)
1207       SR = DAG.getNode(ISD::XOR, dl, MVT::i16, SR, One);
1208     return SR;
1209   } else {
1210     SDValue Zero = DAG.getConstant(0, dl, VT);
1211     SDValue Ops[] = {One, Zero, TargetCC, Flag};
1212     return DAG.getNode(MSP430ISD::SELECT_CC, dl, Op.getValueType(), Ops);
1213   }
1214 }
1215 
1216 SDValue MSP430TargetLowering::LowerSELECT_CC(SDValue Op,
1217                                              SelectionDAG &DAG) const {
1218   SDValue LHS    = Op.getOperand(0);
1219   SDValue RHS    = Op.getOperand(1);
1220   SDValue TrueV  = Op.getOperand(2);
1221   SDValue FalseV = Op.getOperand(3);
1222   ISD::CondCode CC = cast<CondCodeSDNode>(Op.getOperand(4))->get();
1223   SDLoc dl   (Op);
1224 
1225   SDValue TargetCC;
1226   SDValue Flag = EmitCMP(LHS, RHS, TargetCC, CC, dl, DAG);
1227 
1228   SDValue Ops[] = {TrueV, FalseV, TargetCC, Flag};
1229 
1230   return DAG.getNode(MSP430ISD::SELECT_CC, dl, Op.getValueType(), Ops);
1231 }
1232 
1233 SDValue MSP430TargetLowering::LowerSIGN_EXTEND(SDValue Op,
1234                                                SelectionDAG &DAG) const {
1235   SDValue Val = Op.getOperand(0);
1236   EVT VT      = Op.getValueType();
1237   SDLoc dl(Op);
1238 
1239   assert(VT == MVT::i16 && "Only support i16 for now!");
1240 
1241   return DAG.getNode(ISD::SIGN_EXTEND_INREG, dl, VT,
1242                      DAG.getNode(ISD::ANY_EXTEND, dl, VT, Val),
1243                      DAG.getValueType(Val.getValueType()));
1244 }
1245 
1246 SDValue
1247 MSP430TargetLowering::getReturnAddressFrameIndex(SelectionDAG &DAG) const {
1248   MachineFunction &MF = DAG.getMachineFunction();
1249   MSP430MachineFunctionInfo *FuncInfo = MF.getInfo<MSP430MachineFunctionInfo>();
1250   int ReturnAddrIndex = FuncInfo->getRAIndex();
1251   auto PtrVT = getPointerTy(MF.getDataLayout());
1252 
1253   if (ReturnAddrIndex == 0) {
1254     // Set up a frame object for the return address.
1255     uint64_t SlotSize = MF.getDataLayout().getPointerSize();
1256     ReturnAddrIndex = MF.getFrameInfo().CreateFixedObject(SlotSize, -SlotSize,
1257                                                            true);
1258     FuncInfo->setRAIndex(ReturnAddrIndex);
1259   }
1260 
1261   return DAG.getFrameIndex(ReturnAddrIndex, PtrVT);
1262 }
1263 
1264 SDValue MSP430TargetLowering::LowerRETURNADDR(SDValue Op,
1265                                               SelectionDAG &DAG) const {
1266   MachineFrameInfo &MFI = DAG.getMachineFunction().getFrameInfo();
1267   MFI.setReturnAddressIsTaken(true);
1268 
1269   if (verifyReturnAddressArgumentIsConstant(Op, DAG))
1270     return SDValue();
1271 
1272   unsigned Depth = cast<ConstantSDNode>(Op.getOperand(0))->getZExtValue();
1273   SDLoc dl(Op);
1274   auto PtrVT = getPointerTy(DAG.getDataLayout());
1275 
1276   if (Depth > 0) {
1277     SDValue FrameAddr = LowerFRAMEADDR(Op, DAG);
1278     SDValue Offset =
1279         DAG.getConstant(DAG.getDataLayout().getPointerSize(), dl, MVT::i16);
1280     return DAG.getLoad(PtrVT, dl, DAG.getEntryNode(),
1281                        DAG.getNode(ISD::ADD, dl, PtrVT, FrameAddr, Offset),
1282                        MachinePointerInfo());
1283   }
1284 
1285   // Just load the return address.
1286   SDValue RetAddrFI = getReturnAddressFrameIndex(DAG);
1287   return DAG.getLoad(PtrVT, dl, DAG.getEntryNode(), RetAddrFI,
1288                      MachinePointerInfo());
1289 }
1290 
1291 SDValue MSP430TargetLowering::LowerFRAMEADDR(SDValue Op,
1292                                              SelectionDAG &DAG) const {
1293   MachineFrameInfo &MFI = DAG.getMachineFunction().getFrameInfo();
1294   MFI.setFrameAddressIsTaken(true);
1295 
1296   EVT VT = Op.getValueType();
1297   SDLoc dl(Op);  // FIXME probably not meaningful
1298   unsigned Depth = cast<ConstantSDNode>(Op.getOperand(0))->getZExtValue();
1299   SDValue FrameAddr = DAG.getCopyFromReg(DAG.getEntryNode(), dl,
1300                                          MSP430::R4, VT);
1301   while (Depth--)
1302     FrameAddr = DAG.getLoad(VT, dl, DAG.getEntryNode(), FrameAddr,
1303                             MachinePointerInfo());
1304   return FrameAddr;
1305 }
1306 
1307 SDValue MSP430TargetLowering::LowerVASTART(SDValue Op,
1308                                            SelectionDAG &DAG) const {
1309   MachineFunction &MF = DAG.getMachineFunction();
1310   MSP430MachineFunctionInfo *FuncInfo = MF.getInfo<MSP430MachineFunctionInfo>();
1311   auto PtrVT = getPointerTy(DAG.getDataLayout());
1312 
1313   // Frame index of first vararg argument
1314   SDValue FrameIndex =
1315       DAG.getFrameIndex(FuncInfo->getVarArgsFrameIndex(), PtrVT);
1316   const Value *SV = cast<SrcValueSDNode>(Op.getOperand(2))->getValue();
1317 
1318   // Create a store of the frame index to the location operand
1319   return DAG.getStore(Op.getOperand(0), SDLoc(Op), FrameIndex, Op.getOperand(1),
1320                       MachinePointerInfo(SV));
1321 }
1322 
1323 SDValue MSP430TargetLowering::LowerJumpTable(SDValue Op,
1324                                              SelectionDAG &DAG) const {
1325     JumpTableSDNode *JT = cast<JumpTableSDNode>(Op);
1326     auto PtrVT = getPointerTy(DAG.getDataLayout());
1327     SDValue Result = DAG.getTargetJumpTable(JT->getIndex(), PtrVT);
1328     return DAG.getNode(MSP430ISD::Wrapper, SDLoc(JT), PtrVT, Result);
1329 }
1330 
1331 /// getPostIndexedAddressParts - returns true by value, base pointer and
1332 /// offset pointer and addressing mode by reference if this node can be
1333 /// combined with a load / store to form a post-indexed load / store.
1334 bool MSP430TargetLowering::getPostIndexedAddressParts(SDNode *N, SDNode *Op,
1335                                                       SDValue &Base,
1336                                                       SDValue &Offset,
1337                                                       ISD::MemIndexedMode &AM,
1338                                                       SelectionDAG &DAG) const {
1339 
1340   LoadSDNode *LD = cast<LoadSDNode>(N);
1341   if (LD->getExtensionType() != ISD::NON_EXTLOAD)
1342     return false;
1343 
1344   EVT VT = LD->getMemoryVT();
1345   if (VT != MVT::i8 && VT != MVT::i16)
1346     return false;
1347 
1348   if (Op->getOpcode() != ISD::ADD)
1349     return false;
1350 
1351   if (ConstantSDNode *RHS = dyn_cast<ConstantSDNode>(Op->getOperand(1))) {
1352     uint64_t RHSC = RHS->getZExtValue();
1353     if ((VT == MVT::i16 && RHSC != 2) ||
1354         (VT == MVT::i8 && RHSC != 1))
1355       return false;
1356 
1357     Base = Op->getOperand(0);
1358     Offset = DAG.getConstant(RHSC, SDLoc(N), VT);
1359     AM = ISD::POST_INC;
1360     return true;
1361   }
1362 
1363   return false;
1364 }
1365 
1366 
1367 const char *MSP430TargetLowering::getTargetNodeName(unsigned Opcode) const {
1368   switch ((MSP430ISD::NodeType)Opcode) {
1369   case MSP430ISD::FIRST_NUMBER:       break;
1370   case MSP430ISD::RET_FLAG:           return "MSP430ISD::RET_FLAG";
1371   case MSP430ISD::RETI_FLAG:          return "MSP430ISD::RETI_FLAG";
1372   case MSP430ISD::RRA:                return "MSP430ISD::RRA";
1373   case MSP430ISD::RLA:                return "MSP430ISD::RLA";
1374   case MSP430ISD::RRC:                return "MSP430ISD::RRC";
1375   case MSP430ISD::RRCL:               return "MSP430ISD::RRCL";
1376   case MSP430ISD::CALL:               return "MSP430ISD::CALL";
1377   case MSP430ISD::Wrapper:            return "MSP430ISD::Wrapper";
1378   case MSP430ISD::BR_CC:              return "MSP430ISD::BR_CC";
1379   case MSP430ISD::CMP:                return "MSP430ISD::CMP";
1380   case MSP430ISD::SETCC:              return "MSP430ISD::SETCC";
1381   case MSP430ISD::SELECT_CC:          return "MSP430ISD::SELECT_CC";
1382   case MSP430ISD::DADD:               return "MSP430ISD::DADD";
1383   }
1384   return nullptr;
1385 }
1386 
1387 bool MSP430TargetLowering::isTruncateFree(Type *Ty1,
1388                                           Type *Ty2) const {
1389   if (!Ty1->isIntegerTy() || !Ty2->isIntegerTy())
1390     return false;
1391 
1392   return (Ty1->getPrimitiveSizeInBits().getFixedSize() >
1393           Ty2->getPrimitiveSizeInBits().getFixedSize());
1394 }
1395 
1396 bool MSP430TargetLowering::isTruncateFree(EVT VT1, EVT VT2) const {
1397   if (!VT1.isInteger() || !VT2.isInteger())
1398     return false;
1399 
1400   return (VT1.getFixedSizeInBits() > VT2.getFixedSizeInBits());
1401 }
1402 
1403 bool MSP430TargetLowering::isZExtFree(Type *Ty1, Type *Ty2) const {
1404   // MSP430 implicitly zero-extends 8-bit results in 16-bit registers.
1405   return false && Ty1->isIntegerTy(8) && Ty2->isIntegerTy(16);
1406 }
1407 
1408 bool MSP430TargetLowering::isZExtFree(EVT VT1, EVT VT2) const {
1409   // MSP430 implicitly zero-extends 8-bit results in 16-bit registers.
1410   return false && VT1 == MVT::i8 && VT2 == MVT::i16;
1411 }
1412 
1413 bool MSP430TargetLowering::isZExtFree(SDValue Val, EVT VT2) const {
1414   return isZExtFree(Val.getValueType(), VT2);
1415 }
1416 
1417 //===----------------------------------------------------------------------===//
1418 //  Other Lowering Code
1419 //===----------------------------------------------------------------------===//
1420 
1421 MachineBasicBlock *
1422 MSP430TargetLowering::EmitShiftInstr(MachineInstr &MI,
1423                                      MachineBasicBlock *BB) const {
1424   MachineFunction *F = BB->getParent();
1425   MachineRegisterInfo &RI = F->getRegInfo();
1426   DebugLoc dl = MI.getDebugLoc();
1427   const TargetInstrInfo &TII = *F->getSubtarget().getInstrInfo();
1428 
1429   unsigned Opc;
1430   bool ClearCarry = false;
1431   const TargetRegisterClass * RC;
1432   switch (MI.getOpcode()) {
1433   default: llvm_unreachable("Invalid shift opcode!");
1434   case MSP430::Shl8:
1435     Opc = MSP430::ADD8rr;
1436     RC = &MSP430::GR8RegClass;
1437     break;
1438   case MSP430::Shl16:
1439     Opc = MSP430::ADD16rr;
1440     RC = &MSP430::GR16RegClass;
1441     break;
1442   case MSP430::Sra8:
1443     Opc = MSP430::RRA8r;
1444     RC = &MSP430::GR8RegClass;
1445     break;
1446   case MSP430::Sra16:
1447     Opc = MSP430::RRA16r;
1448     RC = &MSP430::GR16RegClass;
1449     break;
1450   case MSP430::Srl8:
1451     ClearCarry = true;
1452     Opc = MSP430::RRC8r;
1453     RC = &MSP430::GR8RegClass;
1454     break;
1455   case MSP430::Srl16:
1456     ClearCarry = true;
1457     Opc = MSP430::RRC16r;
1458     RC = &MSP430::GR16RegClass;
1459     break;
1460   case MSP430::Rrcl8:
1461   case MSP430::Rrcl16: {
1462     BuildMI(*BB, MI, dl, TII.get(MSP430::BIC16rc), MSP430::SR)
1463       .addReg(MSP430::SR).addImm(1);
1464     Register SrcReg = MI.getOperand(1).getReg();
1465     Register DstReg = MI.getOperand(0).getReg();
1466     unsigned RrcOpc = MI.getOpcode() == MSP430::Rrcl16
1467                     ? MSP430::RRC16r : MSP430::RRC8r;
1468     BuildMI(*BB, MI, dl, TII.get(RrcOpc), DstReg)
1469       .addReg(SrcReg);
1470     MI.eraseFromParent(); // The pseudo instruction is gone now.
1471     return BB;
1472   }
1473   }
1474 
1475   const BasicBlock *LLVM_BB = BB->getBasicBlock();
1476   MachineFunction::iterator I = ++BB->getIterator();
1477 
1478   // Create loop block
1479   MachineBasicBlock *LoopBB = F->CreateMachineBasicBlock(LLVM_BB);
1480   MachineBasicBlock *RemBB  = F->CreateMachineBasicBlock(LLVM_BB);
1481 
1482   F->insert(I, LoopBB);
1483   F->insert(I, RemBB);
1484 
1485   // Update machine-CFG edges by transferring all successors of the current
1486   // block to the block containing instructions after shift.
1487   RemBB->splice(RemBB->begin(), BB, std::next(MachineBasicBlock::iterator(MI)),
1488                 BB->end());
1489   RemBB->transferSuccessorsAndUpdatePHIs(BB);
1490 
1491   // Add edges BB => LoopBB => RemBB, BB => RemBB, LoopBB => LoopBB
1492   BB->addSuccessor(LoopBB);
1493   BB->addSuccessor(RemBB);
1494   LoopBB->addSuccessor(RemBB);
1495   LoopBB->addSuccessor(LoopBB);
1496 
1497   Register ShiftAmtReg = RI.createVirtualRegister(&MSP430::GR8RegClass);
1498   Register ShiftAmtReg2 = RI.createVirtualRegister(&MSP430::GR8RegClass);
1499   Register ShiftReg = RI.createVirtualRegister(RC);
1500   Register ShiftReg2 = RI.createVirtualRegister(RC);
1501   Register ShiftAmtSrcReg = MI.getOperand(2).getReg();
1502   Register SrcReg = MI.getOperand(1).getReg();
1503   Register DstReg = MI.getOperand(0).getReg();
1504 
1505   // BB:
1506   // cmp 0, N
1507   // je RemBB
1508   BuildMI(BB, dl, TII.get(MSP430::CMP8ri))
1509     .addReg(ShiftAmtSrcReg).addImm(0);
1510   BuildMI(BB, dl, TII.get(MSP430::JCC))
1511     .addMBB(RemBB)
1512     .addImm(MSP430CC::COND_E);
1513 
1514   // LoopBB:
1515   // ShiftReg = phi [%SrcReg, BB], [%ShiftReg2, LoopBB]
1516   // ShiftAmt = phi [%N, BB],      [%ShiftAmt2, LoopBB]
1517   // ShiftReg2 = shift ShiftReg
1518   // ShiftAmt2 = ShiftAmt - 1;
1519   BuildMI(LoopBB, dl, TII.get(MSP430::PHI), ShiftReg)
1520     .addReg(SrcReg).addMBB(BB)
1521     .addReg(ShiftReg2).addMBB(LoopBB);
1522   BuildMI(LoopBB, dl, TII.get(MSP430::PHI), ShiftAmtReg)
1523     .addReg(ShiftAmtSrcReg).addMBB(BB)
1524     .addReg(ShiftAmtReg2).addMBB(LoopBB);
1525   if (ClearCarry)
1526     BuildMI(LoopBB, dl, TII.get(MSP430::BIC16rc), MSP430::SR)
1527       .addReg(MSP430::SR).addImm(1);
1528   if (Opc == MSP430::ADD8rr || Opc == MSP430::ADD16rr)
1529     BuildMI(LoopBB, dl, TII.get(Opc), ShiftReg2)
1530       .addReg(ShiftReg)
1531       .addReg(ShiftReg);
1532   else
1533     BuildMI(LoopBB, dl, TII.get(Opc), ShiftReg2)
1534       .addReg(ShiftReg);
1535   BuildMI(LoopBB, dl, TII.get(MSP430::SUB8ri), ShiftAmtReg2)
1536     .addReg(ShiftAmtReg).addImm(1);
1537   BuildMI(LoopBB, dl, TII.get(MSP430::JCC))
1538     .addMBB(LoopBB)
1539     .addImm(MSP430CC::COND_NE);
1540 
1541   // RemBB:
1542   // DestReg = phi [%SrcReg, BB], [%ShiftReg, LoopBB]
1543   BuildMI(*RemBB, RemBB->begin(), dl, TII.get(MSP430::PHI), DstReg)
1544     .addReg(SrcReg).addMBB(BB)
1545     .addReg(ShiftReg2).addMBB(LoopBB);
1546 
1547   MI.eraseFromParent(); // The pseudo instruction is gone now.
1548   return RemBB;
1549 }
1550 
1551 MachineBasicBlock *
1552 MSP430TargetLowering::EmitInstrWithCustomInserter(MachineInstr &MI,
1553                                                   MachineBasicBlock *BB) const {
1554   unsigned Opc = MI.getOpcode();
1555 
1556   if (Opc == MSP430::Shl8  || Opc == MSP430::Shl16 ||
1557       Opc == MSP430::Sra8  || Opc == MSP430::Sra16 ||
1558       Opc == MSP430::Srl8  || Opc == MSP430::Srl16 ||
1559       Opc == MSP430::Rrcl8 || Opc == MSP430::Rrcl16)
1560     return EmitShiftInstr(MI, BB);
1561 
1562   const TargetInstrInfo &TII = *BB->getParent()->getSubtarget().getInstrInfo();
1563   DebugLoc dl = MI.getDebugLoc();
1564 
1565   assert((Opc == MSP430::Select16 || Opc == MSP430::Select8) &&
1566          "Unexpected instr type to insert");
1567 
1568   // To "insert" a SELECT instruction, we actually have to insert the diamond
1569   // control-flow pattern.  The incoming instruction knows the destination vreg
1570   // to set, the condition code register to branch on, the true/false values to
1571   // select between, and a branch opcode to use.
1572   const BasicBlock *LLVM_BB = BB->getBasicBlock();
1573   MachineFunction::iterator I = ++BB->getIterator();
1574 
1575   //  thisMBB:
1576   //  ...
1577   //   TrueVal = ...
1578   //   cmpTY ccX, r1, r2
1579   //   jCC copy1MBB
1580   //   fallthrough --> copy0MBB
1581   MachineBasicBlock *thisMBB = BB;
1582   MachineFunction *F = BB->getParent();
1583   MachineBasicBlock *copy0MBB = F->CreateMachineBasicBlock(LLVM_BB);
1584   MachineBasicBlock *copy1MBB = F->CreateMachineBasicBlock(LLVM_BB);
1585   F->insert(I, copy0MBB);
1586   F->insert(I, copy1MBB);
1587   // Update machine-CFG edges by transferring all successors of the current
1588   // block to the new block which will contain the Phi node for the select.
1589   copy1MBB->splice(copy1MBB->begin(), BB,
1590                    std::next(MachineBasicBlock::iterator(MI)), BB->end());
1591   copy1MBB->transferSuccessorsAndUpdatePHIs(BB);
1592   // Next, add the true and fallthrough blocks as its successors.
1593   BB->addSuccessor(copy0MBB);
1594   BB->addSuccessor(copy1MBB);
1595 
1596   BuildMI(BB, dl, TII.get(MSP430::JCC))
1597       .addMBB(copy1MBB)
1598       .addImm(MI.getOperand(3).getImm());
1599 
1600   //  copy0MBB:
1601   //   %FalseValue = ...
1602   //   # fallthrough to copy1MBB
1603   BB = copy0MBB;
1604 
1605   // Update machine-CFG edges
1606   BB->addSuccessor(copy1MBB);
1607 
1608   //  copy1MBB:
1609   //   %Result = phi [ %FalseValue, copy0MBB ], [ %TrueValue, thisMBB ]
1610   //  ...
1611   BB = copy1MBB;
1612   BuildMI(*BB, BB->begin(), dl, TII.get(MSP430::PHI), MI.getOperand(0).getReg())
1613       .addReg(MI.getOperand(2).getReg())
1614       .addMBB(copy0MBB)
1615       .addReg(MI.getOperand(1).getReg())
1616       .addMBB(thisMBB);
1617 
1618   MI.eraseFromParent(); // The pseudo instruction is gone now.
1619   return BB;
1620 }
1621