xref: /freebsd/contrib/llvm-project/llvm/lib/Target/MSP430/MSP430ISelLowering.cpp (revision dd41de95a84d979615a2ef11df6850622bf6184e)
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/SelectionDAGISel.h"
24 #include "llvm/CodeGen/TargetLoweringObjectFileImpl.h"
25 #include "llvm/CodeGen/ValueTypes.h"
26 #include "llvm/IR/CallingConv.h"
27 #include "llvm/IR/DerivedTypes.h"
28 #include "llvm/IR/Function.h"
29 #include "llvm/IR/GlobalAlias.h"
30 #include "llvm/IR/GlobalVariable.h"
31 #include "llvm/IR/Intrinsics.h"
32 #include "llvm/Support/CommandLine.h"
33 #include "llvm/Support/Debug.h"
34 #include "llvm/Support/ErrorHandling.h"
35 #include "llvm/Support/raw_ostream.h"
36 using namespace llvm;
37 
38 #define DEBUG_TYPE "msp430-lower"
39 
40 static cl::opt<bool>MSP430NoLegalImmediate(
41   "msp430-no-legal-immediate", cl::Hidden,
42   cl::desc("Enable non legal immediates (for testing purposes only)"),
43   cl::init(false));
44 
45 MSP430TargetLowering::MSP430TargetLowering(const TargetMachine &TM,
46                                            const MSP430Subtarget &STI)
47     : TargetLowering(TM) {
48 
49   // Set up the register classes.
50   addRegisterClass(MVT::i8,  &MSP430::GR8RegClass);
51   addRegisterClass(MVT::i16, &MSP430::GR16RegClass);
52 
53   // Compute derived properties from the register classes
54   computeRegisterProperties(STI.getRegisterInfo());
55 
56   // Provide all sorts of operation actions
57   setStackPointerRegisterToSaveRestore(MSP430::SP);
58   setBooleanContents(ZeroOrOneBooleanContent);
59   setBooleanVectorContents(ZeroOrOneBooleanContent); // FIXME: Is this correct?
60 
61   // We have post-incremented loads / stores.
62   setIndexedLoadAction(ISD::POST_INC, MVT::i8, Legal);
63   setIndexedLoadAction(ISD::POST_INC, MVT::i16, Legal);
64 
65   for (MVT VT : MVT::integer_valuetypes()) {
66     setLoadExtAction(ISD::EXTLOAD,  VT, MVT::i1,  Promote);
67     setLoadExtAction(ISD::SEXTLOAD, VT, MVT::i1,  Promote);
68     setLoadExtAction(ISD::ZEXTLOAD, VT, MVT::i1,  Promote);
69     setLoadExtAction(ISD::SEXTLOAD, VT, MVT::i8,  Expand);
70     setLoadExtAction(ISD::SEXTLOAD, VT, MVT::i16, Expand);
71   }
72 
73   // We don't have any truncstores
74   setTruncStoreAction(MVT::i16, MVT::i8, Expand);
75 
76   setOperationAction(ISD::SRA,              MVT::i8,    Custom);
77   setOperationAction(ISD::SHL,              MVT::i8,    Custom);
78   setOperationAction(ISD::SRL,              MVT::i8,    Custom);
79   setOperationAction(ISD::SRA,              MVT::i16,   Custom);
80   setOperationAction(ISD::SHL,              MVT::i16,   Custom);
81   setOperationAction(ISD::SRL,              MVT::i16,   Custom);
82   setOperationAction(ISD::ROTL,             MVT::i8,    Expand);
83   setOperationAction(ISD::ROTR,             MVT::i8,    Expand);
84   setOperationAction(ISD::ROTL,             MVT::i16,   Expand);
85   setOperationAction(ISD::ROTR,             MVT::i16,   Expand);
86   setOperationAction(ISD::GlobalAddress,    MVT::i16,   Custom);
87   setOperationAction(ISD::ExternalSymbol,   MVT::i16,   Custom);
88   setOperationAction(ISD::BlockAddress,     MVT::i16,   Custom);
89   setOperationAction(ISD::BR_JT,            MVT::Other, Expand);
90   setOperationAction(ISD::BR_CC,            MVT::i8,    Custom);
91   setOperationAction(ISD::BR_CC,            MVT::i16,   Custom);
92   setOperationAction(ISD::BRCOND,           MVT::Other, Expand);
93   setOperationAction(ISD::SETCC,            MVT::i8,    Custom);
94   setOperationAction(ISD::SETCC,            MVT::i16,   Custom);
95   setOperationAction(ISD::SELECT,           MVT::i8,    Expand);
96   setOperationAction(ISD::SELECT,           MVT::i16,   Expand);
97   setOperationAction(ISD::SELECT_CC,        MVT::i8,    Custom);
98   setOperationAction(ISD::SELECT_CC,        MVT::i16,   Custom);
99   setOperationAction(ISD::SIGN_EXTEND,      MVT::i16,   Custom);
100   setOperationAction(ISD::DYNAMIC_STACKALLOC, MVT::i8, Expand);
101   setOperationAction(ISD::DYNAMIC_STACKALLOC, MVT::i16, Expand);
102   setOperationAction(ISD::STACKSAVE,        MVT::Other, Expand);
103   setOperationAction(ISD::STACKRESTORE,     MVT::Other, Expand);
104 
105   setOperationAction(ISD::CTTZ,             MVT::i8,    Expand);
106   setOperationAction(ISD::CTTZ,             MVT::i16,   Expand);
107   setOperationAction(ISD::CTLZ,             MVT::i8,    Expand);
108   setOperationAction(ISD::CTLZ,             MVT::i16,   Expand);
109   setOperationAction(ISD::CTPOP,            MVT::i8,    Expand);
110   setOperationAction(ISD::CTPOP,            MVT::i16,   Expand);
111 
112   setOperationAction(ISD::SHL_PARTS,        MVT::i8,    Expand);
113   setOperationAction(ISD::SHL_PARTS,        MVT::i16,   Expand);
114   setOperationAction(ISD::SRL_PARTS,        MVT::i8,    Expand);
115   setOperationAction(ISD::SRL_PARTS,        MVT::i16,   Expand);
116   setOperationAction(ISD::SRA_PARTS,        MVT::i8,    Expand);
117   setOperationAction(ISD::SRA_PARTS,        MVT::i16,   Expand);
118 
119   setOperationAction(ISD::SIGN_EXTEND_INREG, MVT::i1,   Expand);
120 
121   // FIXME: Implement efficiently multiplication by a constant
122   setOperationAction(ISD::MUL,              MVT::i8,    Promote);
123   setOperationAction(ISD::MULHS,            MVT::i8,    Promote);
124   setOperationAction(ISD::MULHU,            MVT::i8,    Promote);
125   setOperationAction(ISD::SMUL_LOHI,        MVT::i8,    Promote);
126   setOperationAction(ISD::UMUL_LOHI,        MVT::i8,    Promote);
127   setOperationAction(ISD::MUL,              MVT::i16,   LibCall);
128   setOperationAction(ISD::MULHS,            MVT::i16,   Expand);
129   setOperationAction(ISD::MULHU,            MVT::i16,   Expand);
130   setOperationAction(ISD::SMUL_LOHI,        MVT::i16,   Expand);
131   setOperationAction(ISD::UMUL_LOHI,        MVT::i16,   Expand);
132 
133   setOperationAction(ISD::UDIV,             MVT::i8,    Promote);
134   setOperationAction(ISD::UDIVREM,          MVT::i8,    Promote);
135   setOperationAction(ISD::UREM,             MVT::i8,    Promote);
136   setOperationAction(ISD::SDIV,             MVT::i8,    Promote);
137   setOperationAction(ISD::SDIVREM,          MVT::i8,    Promote);
138   setOperationAction(ISD::SREM,             MVT::i8,    Promote);
139   setOperationAction(ISD::UDIV,             MVT::i16,   LibCall);
140   setOperationAction(ISD::UDIVREM,          MVT::i16,   Expand);
141   setOperationAction(ISD::UREM,             MVT::i16,   LibCall);
142   setOperationAction(ISD::SDIV,             MVT::i16,   LibCall);
143   setOperationAction(ISD::SDIVREM,          MVT::i16,   Expand);
144   setOperationAction(ISD::SREM,             MVT::i16,   LibCall);
145 
146   // varargs support
147   setOperationAction(ISD::VASTART,          MVT::Other, Custom);
148   setOperationAction(ISD::VAARG,            MVT::Other, Expand);
149   setOperationAction(ISD::VAEND,            MVT::Other, Expand);
150   setOperationAction(ISD::VACOPY,           MVT::Other, Expand);
151   setOperationAction(ISD::JumpTable,        MVT::i16,   Custom);
152 
153   // EABI Libcalls - EABI Section 6.2
154   const struct {
155     const RTLIB::Libcall Op;
156     const char * const Name;
157     const ISD::CondCode Cond;
158   } LibraryCalls[] = {
159     // Floating point conversions - EABI Table 6
160     { RTLIB::FPROUND_F64_F32,   "__mspabi_cvtdf",   ISD::SETCC_INVALID },
161     { RTLIB::FPEXT_F32_F64,     "__mspabi_cvtfd",   ISD::SETCC_INVALID },
162     // The following is NOT implemented in libgcc
163     //{ RTLIB::FPTOSINT_F64_I16,  "__mspabi_fixdi", ISD::SETCC_INVALID },
164     { RTLIB::FPTOSINT_F64_I32,  "__mspabi_fixdli",  ISD::SETCC_INVALID },
165     { RTLIB::FPTOSINT_F64_I64,  "__mspabi_fixdlli", ISD::SETCC_INVALID },
166     // The following is NOT implemented in libgcc
167     //{ RTLIB::FPTOUINT_F64_I16,  "__mspabi_fixdu", ISD::SETCC_INVALID },
168     { RTLIB::FPTOUINT_F64_I32,  "__mspabi_fixdul",  ISD::SETCC_INVALID },
169     { RTLIB::FPTOUINT_F64_I64,  "__mspabi_fixdull", ISD::SETCC_INVALID },
170     // The following is NOT implemented in libgcc
171     //{ RTLIB::FPTOSINT_F32_I16,  "__mspabi_fixfi", ISD::SETCC_INVALID },
172     { RTLIB::FPTOSINT_F32_I32,  "__mspabi_fixfli",  ISD::SETCC_INVALID },
173     { RTLIB::FPTOSINT_F32_I64,  "__mspabi_fixflli", ISD::SETCC_INVALID },
174     // The following is NOT implemented in libgcc
175     //{ RTLIB::FPTOUINT_F32_I16,  "__mspabi_fixfu", ISD::SETCC_INVALID },
176     { RTLIB::FPTOUINT_F32_I32,  "__mspabi_fixful",  ISD::SETCC_INVALID },
177     { RTLIB::FPTOUINT_F32_I64,  "__mspabi_fixfull", ISD::SETCC_INVALID },
178     // TODO The following IS implemented in libgcc
179     //{ RTLIB::SINTTOFP_I16_F64,  "__mspabi_fltid", ISD::SETCC_INVALID },
180     { RTLIB::SINTTOFP_I32_F64,  "__mspabi_fltlid",  ISD::SETCC_INVALID },
181     // TODO The following IS implemented in libgcc but is not in the EABI
182     { RTLIB::SINTTOFP_I64_F64,  "__mspabi_fltllid", ISD::SETCC_INVALID },
183     // TODO The following IS implemented in libgcc
184     //{ RTLIB::UINTTOFP_I16_F64,  "__mspabi_fltud", ISD::SETCC_INVALID },
185     { RTLIB::UINTTOFP_I32_F64,  "__mspabi_fltuld",  ISD::SETCC_INVALID },
186     // The following IS implemented in libgcc but is not in the EABI
187     { RTLIB::UINTTOFP_I64_F64,  "__mspabi_fltulld", ISD::SETCC_INVALID },
188     // TODO The following IS implemented in libgcc
189     //{ RTLIB::SINTTOFP_I16_F32,  "__mspabi_fltif", ISD::SETCC_INVALID },
190     { RTLIB::SINTTOFP_I32_F32,  "__mspabi_fltlif",  ISD::SETCC_INVALID },
191     // TODO The following IS implemented in libgcc but is not in the EABI
192     { RTLIB::SINTTOFP_I64_F32,  "__mspabi_fltllif", ISD::SETCC_INVALID },
193     // TODO The following IS implemented in libgcc
194     //{ RTLIB::UINTTOFP_I16_F32,  "__mspabi_fltuf", ISD::SETCC_INVALID },
195     { RTLIB::UINTTOFP_I32_F32,  "__mspabi_fltulf",  ISD::SETCC_INVALID },
196     // The following IS implemented in libgcc but is not in the EABI
197     { RTLIB::UINTTOFP_I64_F32,  "__mspabi_fltullf", ISD::SETCC_INVALID },
198 
199     // Floating point comparisons - EABI Table 7
200     { RTLIB::OEQ_F64, "__mspabi_cmpd", ISD::SETEQ },
201     { RTLIB::UNE_F64, "__mspabi_cmpd", ISD::SETNE },
202     { RTLIB::OGE_F64, "__mspabi_cmpd", ISD::SETGE },
203     { RTLIB::OLT_F64, "__mspabi_cmpd", ISD::SETLT },
204     { RTLIB::OLE_F64, "__mspabi_cmpd", ISD::SETLE },
205     { RTLIB::OGT_F64, "__mspabi_cmpd", ISD::SETGT },
206     { RTLIB::OEQ_F32, "__mspabi_cmpf", ISD::SETEQ },
207     { RTLIB::UNE_F32, "__mspabi_cmpf", ISD::SETNE },
208     { RTLIB::OGE_F32, "__mspabi_cmpf", ISD::SETGE },
209     { RTLIB::OLT_F32, "__mspabi_cmpf", ISD::SETLT },
210     { RTLIB::OLE_F32, "__mspabi_cmpf", ISD::SETLE },
211     { RTLIB::OGT_F32, "__mspabi_cmpf", ISD::SETGT },
212 
213     // Floating point arithmetic - EABI Table 8
214     { RTLIB::ADD_F64,  "__mspabi_addd", ISD::SETCC_INVALID },
215     { RTLIB::ADD_F32,  "__mspabi_addf", ISD::SETCC_INVALID },
216     { RTLIB::DIV_F64,  "__mspabi_divd", ISD::SETCC_INVALID },
217     { RTLIB::DIV_F32,  "__mspabi_divf", ISD::SETCC_INVALID },
218     { RTLIB::MUL_F64,  "__mspabi_mpyd", ISD::SETCC_INVALID },
219     { RTLIB::MUL_F32,  "__mspabi_mpyf", ISD::SETCC_INVALID },
220     { RTLIB::SUB_F64,  "__mspabi_subd", ISD::SETCC_INVALID },
221     { RTLIB::SUB_F32,  "__mspabi_subf", ISD::SETCC_INVALID },
222     // The following are NOT implemented in libgcc
223     // { RTLIB::NEG_F64,  "__mspabi_negd", ISD::SETCC_INVALID },
224     // { RTLIB::NEG_F32,  "__mspabi_negf", ISD::SETCC_INVALID },
225 
226     // Universal Integer Operations - EABI Table 9
227     { RTLIB::SDIV_I16,   "__mspabi_divi", ISD::SETCC_INVALID },
228     { RTLIB::SDIV_I32,   "__mspabi_divli", ISD::SETCC_INVALID },
229     { RTLIB::SDIV_I64,   "__mspabi_divlli", ISD::SETCC_INVALID },
230     { RTLIB::UDIV_I16,   "__mspabi_divu", ISD::SETCC_INVALID },
231     { RTLIB::UDIV_I32,   "__mspabi_divul", ISD::SETCC_INVALID },
232     { RTLIB::UDIV_I64,   "__mspabi_divull", ISD::SETCC_INVALID },
233     { RTLIB::SREM_I16,   "__mspabi_remi", ISD::SETCC_INVALID },
234     { RTLIB::SREM_I32,   "__mspabi_remli", ISD::SETCC_INVALID },
235     { RTLIB::SREM_I64,   "__mspabi_remlli", ISD::SETCC_INVALID },
236     { RTLIB::UREM_I16,   "__mspabi_remu", ISD::SETCC_INVALID },
237     { RTLIB::UREM_I32,   "__mspabi_remul", ISD::SETCC_INVALID },
238     { RTLIB::UREM_I64,   "__mspabi_remull", ISD::SETCC_INVALID },
239 
240     // Bitwise Operations - EABI Table 10
241     // TODO: __mspabi_[srli/srai/slli] ARE implemented in libgcc
242     { RTLIB::SRL_I32,    "__mspabi_srll", ISD::SETCC_INVALID },
243     { RTLIB::SRA_I32,    "__mspabi_sral", ISD::SETCC_INVALID },
244     { RTLIB::SHL_I32,    "__mspabi_slll", ISD::SETCC_INVALID },
245     // __mspabi_[srlll/srall/sllll/rlli/rlll] are NOT implemented in libgcc
246 
247   };
248 
249   for (const auto &LC : LibraryCalls) {
250     setLibcallName(LC.Op, LC.Name);
251     if (LC.Cond != ISD::SETCC_INVALID)
252       setCmpLibcallCC(LC.Op, LC.Cond);
253   }
254 
255   if (STI.hasHWMult16()) {
256     const struct {
257       const RTLIB::Libcall Op;
258       const char * const Name;
259     } LibraryCalls[] = {
260       // Integer Multiply - EABI Table 9
261       { RTLIB::MUL_I16,   "__mspabi_mpyi_hw" },
262       { RTLIB::MUL_I32,   "__mspabi_mpyl_hw" },
263       { RTLIB::MUL_I64,   "__mspabi_mpyll_hw" },
264       // TODO The __mspabi_mpysl*_hw functions ARE implemented in libgcc
265       // TODO The __mspabi_mpyul*_hw functions ARE implemented in libgcc
266     };
267     for (const auto &LC : LibraryCalls) {
268       setLibcallName(LC.Op, LC.Name);
269     }
270   } else if (STI.hasHWMult32()) {
271     const struct {
272       const RTLIB::Libcall Op;
273       const char * const Name;
274     } LibraryCalls[] = {
275       // Integer Multiply - EABI Table 9
276       { RTLIB::MUL_I16,   "__mspabi_mpyi_hw" },
277       { RTLIB::MUL_I32,   "__mspabi_mpyl_hw32" },
278       { RTLIB::MUL_I64,   "__mspabi_mpyll_hw32" },
279       // TODO The __mspabi_mpysl*_hw32 functions ARE implemented in libgcc
280       // TODO The __mspabi_mpyul*_hw32 functions ARE implemented in libgcc
281     };
282     for (const auto &LC : LibraryCalls) {
283       setLibcallName(LC.Op, LC.Name);
284     }
285   } else if (STI.hasHWMultF5()) {
286     const struct {
287       const RTLIB::Libcall Op;
288       const char * const Name;
289     } LibraryCalls[] = {
290       // Integer Multiply - EABI Table 9
291       { RTLIB::MUL_I16,   "__mspabi_mpyi_f5hw" },
292       { RTLIB::MUL_I32,   "__mspabi_mpyl_f5hw" },
293       { RTLIB::MUL_I64,   "__mspabi_mpyll_f5hw" },
294       // TODO The __mspabi_mpysl*_f5hw functions ARE implemented in libgcc
295       // TODO The __mspabi_mpyul*_f5hw functions ARE implemented in libgcc
296     };
297     for (const auto &LC : LibraryCalls) {
298       setLibcallName(LC.Op, LC.Name);
299     }
300   } else { // NoHWMult
301     const struct {
302       const RTLIB::Libcall Op;
303       const char * const Name;
304     } LibraryCalls[] = {
305       // Integer Multiply - EABI Table 9
306       { RTLIB::MUL_I16,   "__mspabi_mpyi" },
307       { RTLIB::MUL_I32,   "__mspabi_mpyl" },
308       { RTLIB::MUL_I64,   "__mspabi_mpyll" },
309       // The __mspabi_mpysl* functions are NOT implemented in libgcc
310       // The __mspabi_mpyul* functions are NOT implemented in libgcc
311     };
312     for (const auto &LC : LibraryCalls) {
313       setLibcallName(LC.Op, LC.Name);
314     }
315     setLibcallCallingConv(RTLIB::MUL_I64, CallingConv::MSP430_BUILTIN);
316   }
317 
318   // Several of the runtime library functions use a special calling conv
319   setLibcallCallingConv(RTLIB::UDIV_I64, CallingConv::MSP430_BUILTIN);
320   setLibcallCallingConv(RTLIB::UREM_I64, CallingConv::MSP430_BUILTIN);
321   setLibcallCallingConv(RTLIB::SDIV_I64, CallingConv::MSP430_BUILTIN);
322   setLibcallCallingConv(RTLIB::SREM_I64, CallingConv::MSP430_BUILTIN);
323   setLibcallCallingConv(RTLIB::ADD_F64, CallingConv::MSP430_BUILTIN);
324   setLibcallCallingConv(RTLIB::SUB_F64, CallingConv::MSP430_BUILTIN);
325   setLibcallCallingConv(RTLIB::MUL_F64, CallingConv::MSP430_BUILTIN);
326   setLibcallCallingConv(RTLIB::DIV_F64, CallingConv::MSP430_BUILTIN);
327   setLibcallCallingConv(RTLIB::OEQ_F64, CallingConv::MSP430_BUILTIN);
328   setLibcallCallingConv(RTLIB::UNE_F64, CallingConv::MSP430_BUILTIN);
329   setLibcallCallingConv(RTLIB::OGE_F64, CallingConv::MSP430_BUILTIN);
330   setLibcallCallingConv(RTLIB::OLT_F64, CallingConv::MSP430_BUILTIN);
331   setLibcallCallingConv(RTLIB::OLE_F64, CallingConv::MSP430_BUILTIN);
332   setLibcallCallingConv(RTLIB::OGT_F64, CallingConv::MSP430_BUILTIN);
333   // TODO: __mspabi_srall, __mspabi_srlll, __mspabi_sllll
334 
335   setMinFunctionAlignment(Align(2));
336   setPrefFunctionAlignment(Align(2));
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 = array_lengthof(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 = array_lengthof(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.getNextStackOffset();
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.getEVTString() << "\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       // Sanity check
675       assert(VA.isMemLoc());
676 
677       SDValue InVal;
678       ISD::ArgFlagsTy Flags = Ins[i].Flags;
679 
680       if (Flags.isByVal()) {
681         int FI = MFI.CreateFixedObject(Flags.getByValSize(),
682                                        VA.getLocMemOffset(), true);
683         InVal = DAG.getFrameIndex(FI, getPointerTy(DAG.getDataLayout()));
684       } else {
685         // Load the argument to a virtual register
686         unsigned ObjSize = VA.getLocVT().getSizeInBits()/8;
687         if (ObjSize > 2) {
688             errs() << "LowerFormalArguments Unhandled argument type: "
689                 << EVT(VA.getLocVT()).getEVTString()
690                 << "\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       unsigned 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 Flag;
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], Flag);
767 
768     // Guarantee that all emitted copies are stuck together,
769     // avoiding something bad.
770     Flag = 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     unsigned Reg = FuncInfo->getSRetReturnReg();
777 
778     if (!Reg)
779       llvm_unreachable("sret virtual register not created in entry block");
780 
781     SDValue Val =
782       DAG.getCopyFromReg(Chain, dl, Reg, getPointerTy(DAG.getDataLayout()));
783     unsigned R12 = MSP430::R12;
784 
785     Chain = DAG.getCopyToReg(Chain, dl, R12, Val, Flag);
786     Flag = Chain.getValue(1);
787     RetOps.push_back(DAG.getRegister(R12, getPointerTy(DAG.getDataLayout())));
788   }
789 
790   unsigned Opc = (CallConv == CallingConv::MSP430_INTR ?
791                   MSP430ISD::RETI_FLAG : MSP430ISD::RET_FLAG);
792 
793   RetOps[0] = Chain;  // Update chain.
794 
795   // Add the flag if we have it.
796   if (Flag.getNode())
797     RetOps.push_back(Flag);
798 
799   return DAG.getNode(Opc, dl, MVT::Other, RetOps);
800 }
801 
802 /// LowerCCCCallTo - functions arguments are copied from virtual regs to
803 /// (physical regs)/(stack frame), CALLSEQ_START and CALLSEQ_END are emitted.
804 SDValue MSP430TargetLowering::LowerCCCCallTo(
805     SDValue Chain, SDValue Callee, CallingConv::ID CallConv, bool isVarArg,
806     bool isTailCall, const SmallVectorImpl<ISD::OutputArg> &Outs,
807     const SmallVectorImpl<SDValue> &OutVals,
808     const SmallVectorImpl<ISD::InputArg> &Ins, const SDLoc &dl,
809     SelectionDAG &DAG, SmallVectorImpl<SDValue> &InVals) const {
810   // Analyze operands of the call, assigning locations to each operand.
811   SmallVector<CCValAssign, 16> ArgLocs;
812   CCState CCInfo(CallConv, isVarArg, DAG.getMachineFunction(), ArgLocs,
813                  *DAG.getContext());
814   AnalyzeArguments(CCInfo, ArgLocs, Outs);
815 
816   // Get a count of how many bytes are to be pushed on the stack.
817   unsigned NumBytes = CCInfo.getNextStackOffset();
818   auto PtrVT = getPointerTy(DAG.getDataLayout());
819 
820   Chain = DAG.getCALLSEQ_START(Chain, NumBytes, 0, dl);
821 
822   SmallVector<std::pair<unsigned, SDValue>, 4> RegsToPass;
823   SmallVector<SDValue, 12> MemOpChains;
824   SDValue StackPtr;
825 
826   // Walk the register/memloc assignments, inserting copies/loads.
827   for (unsigned i = 0, e = ArgLocs.size(); i != e; ++i) {
828     CCValAssign &VA = ArgLocs[i];
829 
830     SDValue Arg = OutVals[i];
831 
832     // Promote the value if needed.
833     switch (VA.getLocInfo()) {
834       default: llvm_unreachable("Unknown loc info!");
835       case CCValAssign::Full: break;
836       case CCValAssign::SExt:
837         Arg = DAG.getNode(ISD::SIGN_EXTEND, dl, VA.getLocVT(), Arg);
838         break;
839       case CCValAssign::ZExt:
840         Arg = DAG.getNode(ISD::ZERO_EXTEND, dl, VA.getLocVT(), Arg);
841         break;
842       case CCValAssign::AExt:
843         Arg = DAG.getNode(ISD::ANY_EXTEND, dl, VA.getLocVT(), Arg);
844         break;
845     }
846 
847     // Arguments that can be passed on register must be kept at RegsToPass
848     // vector
849     if (VA.isRegLoc()) {
850       RegsToPass.push_back(std::make_pair(VA.getLocReg(), Arg));
851     } else {
852       assert(VA.isMemLoc());
853 
854       if (!StackPtr.getNode())
855         StackPtr = DAG.getCopyFromReg(Chain, dl, MSP430::SP, PtrVT);
856 
857       SDValue PtrOff =
858           DAG.getNode(ISD::ADD, dl, PtrVT, StackPtr,
859                       DAG.getIntPtrConstant(VA.getLocMemOffset(), dl));
860 
861       SDValue MemOp;
862       ISD::ArgFlagsTy Flags = Outs[i].Flags;
863 
864       if (Flags.isByVal()) {
865         SDValue SizeNode = DAG.getConstant(Flags.getByValSize(), dl, MVT::i16);
866         MemOp = DAG.getMemcpy(
867             Chain, dl, PtrOff, Arg, SizeNode, Flags.getNonZeroByValAlign(),
868             /*isVolatile*/ false,
869             /*AlwaysInline=*/true,
870             /*isTailCall=*/false, MachinePointerInfo(), MachinePointerInfo());
871       } else {
872         MemOp = DAG.getStore(Chain, dl, Arg, PtrOff, MachinePointerInfo());
873       }
874 
875       MemOpChains.push_back(MemOp);
876     }
877   }
878 
879   // Transform all store nodes into one single node because all store nodes are
880   // independent of each other.
881   if (!MemOpChains.empty())
882     Chain = DAG.getNode(ISD::TokenFactor, dl, MVT::Other, MemOpChains);
883 
884   // Build a sequence of copy-to-reg nodes chained together with token chain and
885   // flag operands which copy the outgoing args into registers.  The InFlag in
886   // necessary since all emitted instructions must be stuck together.
887   SDValue InFlag;
888   for (unsigned i = 0, e = RegsToPass.size(); i != e; ++i) {
889     Chain = DAG.getCopyToReg(Chain, dl, RegsToPass[i].first,
890                              RegsToPass[i].second, InFlag);
891     InFlag = Chain.getValue(1);
892   }
893 
894   // If the callee is a GlobalAddress node (quite common, every direct call is)
895   // turn it into a TargetGlobalAddress node so that legalize doesn't hack it.
896   // Likewise ExternalSymbol -> TargetExternalSymbol.
897   if (GlobalAddressSDNode *G = dyn_cast<GlobalAddressSDNode>(Callee))
898     Callee = DAG.getTargetGlobalAddress(G->getGlobal(), dl, MVT::i16);
899   else if (ExternalSymbolSDNode *E = dyn_cast<ExternalSymbolSDNode>(Callee))
900     Callee = DAG.getTargetExternalSymbol(E->getSymbol(), MVT::i16);
901 
902   // Returns a chain & a flag for retval copy to use.
903   SDVTList NodeTys = DAG.getVTList(MVT::Other, MVT::Glue);
904   SmallVector<SDValue, 8> Ops;
905   Ops.push_back(Chain);
906   Ops.push_back(Callee);
907 
908   // Add argument registers to the end of the list so that they are
909   // known live into the call.
910   for (unsigned i = 0, e = RegsToPass.size(); i != e; ++i)
911     Ops.push_back(DAG.getRegister(RegsToPass[i].first,
912                                   RegsToPass[i].second.getValueType()));
913 
914   if (InFlag.getNode())
915     Ops.push_back(InFlag);
916 
917   Chain = DAG.getNode(MSP430ISD::CALL, dl, NodeTys, Ops);
918   InFlag = Chain.getValue(1);
919 
920   // Create the CALLSEQ_END node.
921   Chain = DAG.getCALLSEQ_END(Chain, DAG.getConstant(NumBytes, dl, PtrVT, true),
922                              DAG.getConstant(0, dl, PtrVT, true), InFlag, dl);
923   InFlag = Chain.getValue(1);
924 
925   // Handle result values, copying them out of physregs into vregs that we
926   // return.
927   return LowerCallResult(Chain, InFlag, 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 InFlag, 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(), InFlag).getValue(1);
950     InFlag = 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 = cast<ConstantSDNode>(N->getOperand(1))->getZExtValue();
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   auto PtrVT = getPointerTy(DAG.getDataLayout());
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   auto PtrVT = getPointerTy(DAG.getDataLayout());
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   auto PtrVT = getPointerTy(DAG.getDataLayout());
1035   const BlockAddress *BA = cast<BlockAddressSDNode>(Op)->getBlockAddress();
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     LLVM_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     LLVM_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     LLVM_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     LLVM_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->isNullValue() && 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 (cast<ConstantSDNode>(TargetCC)->getZExtValue()) {
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     SDVTList VTs = DAG.getVTList(Op.getValueType(), MVT::Glue);
1213     SDValue Ops[] = {One, Zero, TargetCC, Flag};
1214     return DAG.getNode(MSP430ISD::SELECT_CC, dl, VTs, Ops);
1215   }
1216 }
1217 
1218 SDValue MSP430TargetLowering::LowerSELECT_CC(SDValue Op,
1219                                              SelectionDAG &DAG) const {
1220   SDValue LHS    = Op.getOperand(0);
1221   SDValue RHS    = Op.getOperand(1);
1222   SDValue TrueV  = Op.getOperand(2);
1223   SDValue FalseV = Op.getOperand(3);
1224   ISD::CondCode CC = cast<CondCodeSDNode>(Op.getOperand(4))->get();
1225   SDLoc dl   (Op);
1226 
1227   SDValue TargetCC;
1228   SDValue Flag = EmitCMP(LHS, RHS, TargetCC, CC, dl, DAG);
1229 
1230   SDVTList VTs = DAG.getVTList(Op.getValueType(), MVT::Glue);
1231   SDValue Ops[] = {TrueV, FalseV, TargetCC, Flag};
1232 
1233   return DAG.getNode(MSP430ISD::SELECT_CC, dl, VTs, Ops);
1234 }
1235 
1236 SDValue MSP430TargetLowering::LowerSIGN_EXTEND(SDValue Op,
1237                                                SelectionDAG &DAG) const {
1238   SDValue Val = Op.getOperand(0);
1239   EVT VT      = Op.getValueType();
1240   SDLoc dl(Op);
1241 
1242   assert(VT == MVT::i16 && "Only support i16 for now!");
1243 
1244   return DAG.getNode(ISD::SIGN_EXTEND_INREG, dl, VT,
1245                      DAG.getNode(ISD::ANY_EXTEND, dl, VT, Val),
1246                      DAG.getValueType(Val.getValueType()));
1247 }
1248 
1249 SDValue
1250 MSP430TargetLowering::getReturnAddressFrameIndex(SelectionDAG &DAG) const {
1251   MachineFunction &MF = DAG.getMachineFunction();
1252   MSP430MachineFunctionInfo *FuncInfo = MF.getInfo<MSP430MachineFunctionInfo>();
1253   int ReturnAddrIndex = FuncInfo->getRAIndex();
1254   auto PtrVT = getPointerTy(MF.getDataLayout());
1255 
1256   if (ReturnAddrIndex == 0) {
1257     // Set up a frame object for the return address.
1258     uint64_t SlotSize = MF.getDataLayout().getPointerSize();
1259     ReturnAddrIndex = MF.getFrameInfo().CreateFixedObject(SlotSize, -SlotSize,
1260                                                            true);
1261     FuncInfo->setRAIndex(ReturnAddrIndex);
1262   }
1263 
1264   return DAG.getFrameIndex(ReturnAddrIndex, PtrVT);
1265 }
1266 
1267 SDValue MSP430TargetLowering::LowerRETURNADDR(SDValue Op,
1268                                               SelectionDAG &DAG) const {
1269   MachineFrameInfo &MFI = DAG.getMachineFunction().getFrameInfo();
1270   MFI.setReturnAddressIsTaken(true);
1271 
1272   if (verifyReturnAddressArgumentIsConstant(Op, DAG))
1273     return SDValue();
1274 
1275   unsigned Depth = cast<ConstantSDNode>(Op.getOperand(0))->getZExtValue();
1276   SDLoc dl(Op);
1277   auto PtrVT = getPointerTy(DAG.getDataLayout());
1278 
1279   if (Depth > 0) {
1280     SDValue FrameAddr = LowerFRAMEADDR(Op, DAG);
1281     SDValue Offset =
1282         DAG.getConstant(DAG.getDataLayout().getPointerSize(), dl, MVT::i16);
1283     return DAG.getLoad(PtrVT, dl, DAG.getEntryNode(),
1284                        DAG.getNode(ISD::ADD, dl, PtrVT, FrameAddr, Offset),
1285                        MachinePointerInfo());
1286   }
1287 
1288   // Just load the return address.
1289   SDValue RetAddrFI = getReturnAddressFrameIndex(DAG);
1290   return DAG.getLoad(PtrVT, dl, DAG.getEntryNode(), RetAddrFI,
1291                      MachinePointerInfo());
1292 }
1293 
1294 SDValue MSP430TargetLowering::LowerFRAMEADDR(SDValue Op,
1295                                              SelectionDAG &DAG) const {
1296   MachineFrameInfo &MFI = DAG.getMachineFunction().getFrameInfo();
1297   MFI.setFrameAddressIsTaken(true);
1298 
1299   EVT VT = Op.getValueType();
1300   SDLoc dl(Op);  // FIXME probably not meaningful
1301   unsigned Depth = cast<ConstantSDNode>(Op.getOperand(0))->getZExtValue();
1302   SDValue FrameAddr = DAG.getCopyFromReg(DAG.getEntryNode(), dl,
1303                                          MSP430::R4, VT);
1304   while (Depth--)
1305     FrameAddr = DAG.getLoad(VT, dl, DAG.getEntryNode(), FrameAddr,
1306                             MachinePointerInfo());
1307   return FrameAddr;
1308 }
1309 
1310 SDValue MSP430TargetLowering::LowerVASTART(SDValue Op,
1311                                            SelectionDAG &DAG) const {
1312   MachineFunction &MF = DAG.getMachineFunction();
1313   MSP430MachineFunctionInfo *FuncInfo = MF.getInfo<MSP430MachineFunctionInfo>();
1314   auto PtrVT = getPointerTy(DAG.getDataLayout());
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, Op.getOperand(1),
1323                       MachinePointerInfo(SV));
1324 }
1325 
1326 SDValue MSP430TargetLowering::LowerJumpTable(SDValue Op,
1327                                              SelectionDAG &DAG) const {
1328     JumpTableSDNode *JT = cast<JumpTableSDNode>(Op);
1329     auto PtrVT = getPointerTy(DAG.getDataLayout());
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_FLAG:           return "MSP430ISD::RET_FLAG";
1374   case MSP430ISD::RETI_FLAG:          return "MSP430ISD::RETI_FLAG";
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() > Ty2->getPrimitiveSizeInBits());
1396 }
1397 
1398 bool MSP430TargetLowering::isTruncateFree(EVT VT1, EVT VT2) const {
1399   if (!VT1.isInteger() || !VT2.isInteger())
1400     return false;
1401 
1402   return (VT1.getSizeInBits() > VT2.getSizeInBits());
1403 }
1404 
1405 bool MSP430TargetLowering::isZExtFree(Type *Ty1, Type *Ty2) const {
1406   // MSP430 implicitly zero-extends 8-bit results in 16-bit registers.
1407   return 0 && Ty1->isIntegerTy(8) && Ty2->isIntegerTy(16);
1408 }
1409 
1410 bool MSP430TargetLowering::isZExtFree(EVT VT1, EVT VT2) const {
1411   // MSP430 implicitly zero-extends 8-bit results in 16-bit registers.
1412   return 0 && VT1 == MVT::i8 && VT2 == MVT::i16;
1413 }
1414 
1415 bool MSP430TargetLowering::isZExtFree(SDValue Val, EVT VT2) const {
1416   return isZExtFree(Val.getValueType(), VT2);
1417 }
1418 
1419 //===----------------------------------------------------------------------===//
1420 //  Other Lowering Code
1421 //===----------------------------------------------------------------------===//
1422 
1423 MachineBasicBlock *
1424 MSP430TargetLowering::EmitShiftInstr(MachineInstr &MI,
1425                                      MachineBasicBlock *BB) const {
1426   MachineFunction *F = BB->getParent();
1427   MachineRegisterInfo &RI = F->getRegInfo();
1428   DebugLoc dl = MI.getDebugLoc();
1429   const TargetInstrInfo &TII = *F->getSubtarget().getInstrInfo();
1430 
1431   unsigned Opc;
1432   bool ClearCarry = false;
1433   const TargetRegisterClass * RC;
1434   switch (MI.getOpcode()) {
1435   default: llvm_unreachable("Invalid shift opcode!");
1436   case MSP430::Shl8:
1437     Opc = MSP430::ADD8rr;
1438     RC = &MSP430::GR8RegClass;
1439     break;
1440   case MSP430::Shl16:
1441     Opc = MSP430::ADD16rr;
1442     RC = &MSP430::GR16RegClass;
1443     break;
1444   case MSP430::Sra8:
1445     Opc = MSP430::RRA8r;
1446     RC = &MSP430::GR8RegClass;
1447     break;
1448   case MSP430::Sra16:
1449     Opc = MSP430::RRA16r;
1450     RC = &MSP430::GR16RegClass;
1451     break;
1452   case MSP430::Srl8:
1453     ClearCarry = true;
1454     Opc = MSP430::RRC8r;
1455     RC = &MSP430::GR8RegClass;
1456     break;
1457   case MSP430::Srl16:
1458     ClearCarry = true;
1459     Opc = MSP430::RRC16r;
1460     RC = &MSP430::GR16RegClass;
1461     break;
1462   case MSP430::Rrcl8:
1463   case MSP430::Rrcl16: {
1464     BuildMI(*BB, MI, dl, TII.get(MSP430::BIC16rc), MSP430::SR)
1465       .addReg(MSP430::SR).addImm(1);
1466     Register SrcReg = MI.getOperand(1).getReg();
1467     Register DstReg = MI.getOperand(0).getReg();
1468     unsigned RrcOpc = MI.getOpcode() == MSP430::Rrcl16
1469                     ? MSP430::RRC16r : MSP430::RRC8r;
1470     BuildMI(*BB, MI, dl, TII.get(RrcOpc), DstReg)
1471       .addReg(SrcReg);
1472     MI.eraseFromParent(); // The pseudo instruction is gone now.
1473     return BB;
1474   }
1475   }
1476 
1477   const BasicBlock *LLVM_BB = BB->getBasicBlock();
1478   MachineFunction::iterator I = ++BB->getIterator();
1479 
1480   // Create loop block
1481   MachineBasicBlock *LoopBB = F->CreateMachineBasicBlock(LLVM_BB);
1482   MachineBasicBlock *RemBB  = F->CreateMachineBasicBlock(LLVM_BB);
1483 
1484   F->insert(I, LoopBB);
1485   F->insert(I, RemBB);
1486 
1487   // Update machine-CFG edges by transferring all successors of the current
1488   // block to the block containing instructions after shift.
1489   RemBB->splice(RemBB->begin(), BB, std::next(MachineBasicBlock::iterator(MI)),
1490                 BB->end());
1491   RemBB->transferSuccessorsAndUpdatePHIs(BB);
1492 
1493   // Add edges BB => LoopBB => RemBB, BB => RemBB, LoopBB => LoopBB
1494   BB->addSuccessor(LoopBB);
1495   BB->addSuccessor(RemBB);
1496   LoopBB->addSuccessor(RemBB);
1497   LoopBB->addSuccessor(LoopBB);
1498 
1499   Register ShiftAmtReg = RI.createVirtualRegister(&MSP430::GR8RegClass);
1500   Register ShiftAmtReg2 = RI.createVirtualRegister(&MSP430::GR8RegClass);
1501   Register ShiftReg = RI.createVirtualRegister(RC);
1502   Register ShiftReg2 = RI.createVirtualRegister(RC);
1503   Register ShiftAmtSrcReg = MI.getOperand(2).getReg();
1504   Register SrcReg = MI.getOperand(1).getReg();
1505   Register DstReg = MI.getOperand(0).getReg();
1506 
1507   // BB:
1508   // cmp 0, N
1509   // je RemBB
1510   BuildMI(BB, dl, TII.get(MSP430::CMP8ri))
1511     .addReg(ShiftAmtSrcReg).addImm(0);
1512   BuildMI(BB, dl, TII.get(MSP430::JCC))
1513     .addMBB(RemBB)
1514     .addImm(MSP430CC::COND_E);
1515 
1516   // LoopBB:
1517   // ShiftReg = phi [%SrcReg, BB], [%ShiftReg2, LoopBB]
1518   // ShiftAmt = phi [%N, BB],      [%ShiftAmt2, LoopBB]
1519   // ShiftReg2 = shift ShiftReg
1520   // ShiftAmt2 = ShiftAmt - 1;
1521   BuildMI(LoopBB, dl, TII.get(MSP430::PHI), ShiftReg)
1522     .addReg(SrcReg).addMBB(BB)
1523     .addReg(ShiftReg2).addMBB(LoopBB);
1524   BuildMI(LoopBB, dl, TII.get(MSP430::PHI), ShiftAmtReg)
1525     .addReg(ShiftAmtSrcReg).addMBB(BB)
1526     .addReg(ShiftAmtReg2).addMBB(LoopBB);
1527   if (ClearCarry)
1528     BuildMI(LoopBB, dl, TII.get(MSP430::BIC16rc), MSP430::SR)
1529       .addReg(MSP430::SR).addImm(1);
1530   if (Opc == MSP430::ADD8rr || Opc == MSP430::ADD16rr)
1531     BuildMI(LoopBB, dl, TII.get(Opc), ShiftReg2)
1532       .addReg(ShiftReg)
1533       .addReg(ShiftReg);
1534   else
1535     BuildMI(LoopBB, dl, TII.get(Opc), ShiftReg2)
1536       .addReg(ShiftReg);
1537   BuildMI(LoopBB, dl, TII.get(MSP430::SUB8ri), ShiftAmtReg2)
1538     .addReg(ShiftAmtReg).addImm(1);
1539   BuildMI(LoopBB, dl, TII.get(MSP430::JCC))
1540     .addMBB(LoopBB)
1541     .addImm(MSP430CC::COND_NE);
1542 
1543   // RemBB:
1544   // DestReg = phi [%SrcReg, BB], [%ShiftReg, LoopBB]
1545   BuildMI(*RemBB, RemBB->begin(), dl, TII.get(MSP430::PHI), DstReg)
1546     .addReg(SrcReg).addMBB(BB)
1547     .addReg(ShiftReg2).addMBB(LoopBB);
1548 
1549   MI.eraseFromParent(); // The pseudo instruction is gone now.
1550   return RemBB;
1551 }
1552 
1553 MachineBasicBlock *
1554 MSP430TargetLowering::EmitInstrWithCustomInserter(MachineInstr &MI,
1555                                                   MachineBasicBlock *BB) const {
1556   unsigned Opc = MI.getOpcode();
1557 
1558   if (Opc == MSP430::Shl8  || Opc == MSP430::Shl16 ||
1559       Opc == MSP430::Sra8  || Opc == MSP430::Sra16 ||
1560       Opc == MSP430::Srl8  || Opc == MSP430::Srl16 ||
1561       Opc == MSP430::Rrcl8 || Opc == MSP430::Rrcl16)
1562     return EmitShiftInstr(MI, BB);
1563 
1564   const TargetInstrInfo &TII = *BB->getParent()->getSubtarget().getInstrInfo();
1565   DebugLoc dl = MI.getDebugLoc();
1566 
1567   assert((Opc == MSP430::Select16 || Opc == MSP430::Select8) &&
1568          "Unexpected instr type to insert");
1569 
1570   // To "insert" a SELECT instruction, we actually have to insert the diamond
1571   // control-flow pattern.  The incoming instruction knows the destination vreg
1572   // to set, the condition code register to branch on, the true/false values to
1573   // select between, and a branch opcode to use.
1574   const BasicBlock *LLVM_BB = BB->getBasicBlock();
1575   MachineFunction::iterator I = ++BB->getIterator();
1576 
1577   //  thisMBB:
1578   //  ...
1579   //   TrueVal = ...
1580   //   cmpTY ccX, r1, r2
1581   //   jCC copy1MBB
1582   //   fallthrough --> copy0MBB
1583   MachineBasicBlock *thisMBB = BB;
1584   MachineFunction *F = BB->getParent();
1585   MachineBasicBlock *copy0MBB = F->CreateMachineBasicBlock(LLVM_BB);
1586   MachineBasicBlock *copy1MBB = F->CreateMachineBasicBlock(LLVM_BB);
1587   F->insert(I, copy0MBB);
1588   F->insert(I, copy1MBB);
1589   // Update machine-CFG edges by transferring all successors of the current
1590   // block to the new block which will contain the Phi node for the select.
1591   copy1MBB->splice(copy1MBB->begin(), BB,
1592                    std::next(MachineBasicBlock::iterator(MI)), BB->end());
1593   copy1MBB->transferSuccessorsAndUpdatePHIs(BB);
1594   // Next, add the true and fallthrough blocks as its successors.
1595   BB->addSuccessor(copy0MBB);
1596   BB->addSuccessor(copy1MBB);
1597 
1598   BuildMI(BB, dl, TII.get(MSP430::JCC))
1599       .addMBB(copy1MBB)
1600       .addImm(MI.getOperand(3).getImm());
1601 
1602   //  copy0MBB:
1603   //   %FalseValue = ...
1604   //   # fallthrough to copy1MBB
1605   BB = copy0MBB;
1606 
1607   // Update machine-CFG edges
1608   BB->addSuccessor(copy1MBB);
1609 
1610   //  copy1MBB:
1611   //   %Result = phi [ %FalseValue, copy0MBB ], [ %TrueValue, thisMBB ]
1612   //  ...
1613   BB = copy1MBB;
1614   BuildMI(*BB, BB->begin(), dl, TII.get(MSP430::PHI), MI.getOperand(0).getReg())
1615       .addReg(MI.getOperand(2).getReg())
1616       .addMBB(copy0MBB)
1617       .addReg(MI.getOperand(1).getReg())
1618       .addMBB(thisMBB);
1619 
1620   MI.eraseFromParent(); // The pseudo instruction is gone now.
1621   return BB;
1622 }
1623