1 ///===-- FastISel.cpp - Implementation of the FastISel class --------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file contains the implementation of the FastISel class.
12 //===----------------------------------------------------------------------===//
14 #include "llvm/Instructions.h"
15 #include "llvm/CodeGen/FastISel.h"
16 #include "llvm/CodeGen/MachineInstrBuilder.h"
17 #include "llvm/CodeGen/MachineRegisterInfo.h"
18 #include "llvm/Target/TargetData.h"
19 #include "llvm/Target/TargetInstrInfo.h"
20 #include "llvm/Target/TargetLowering.h"
21 #include "llvm/Target/TargetMachine.h"
24 /// SelectBinaryOp - Select and emit code for a binary operator instruction,
25 /// which has an opcode which directly corresponds to the given ISD opcode.
27 bool FastISel::SelectBinaryOp(Instruction *I, ISD::NodeType ISDOpcode,
28 DenseMap<const Value*, unsigned> &ValueMap) {
29 MVT VT = MVT::getMVT(I->getType(), /*HandleUnknown=*/true);
30 if (VT == MVT::Other || !VT.isSimple())
31 // Unhandled type. Halt "fast" selection and bail.
33 // We only handle legal types. For example, on x86-32 the instruction
34 // selector contains all of the 64-bit instructions from x86-64,
35 // under the assumption that i64 won't be used if the target doesn't
37 if (!TLI.isTypeLegal(VT))
40 unsigned Op0 = ValueMap[I->getOperand(0)];
42 // Unhandled operand. Halt "fast" selection and bail.
45 // Check if the second operand is a constant and handle it appropriately.
46 if (ConstantInt *CI = dyn_cast<ConstantInt>(I->getOperand(1))) {
47 unsigned ResultReg = FastEmit_ri_(VT.getSimpleVT(), ISDOpcode, Op0,
48 CI->getZExtValue(), VT.getSimpleVT());
50 // Target-specific code wasn't able to find a machine opcode for
51 // the given ISD opcode and type. Halt "fast" selection and bail.
54 // We successfully emitted code for the given LLVM Instruction.
55 ValueMap[I] = ResultReg;
59 unsigned Op1 = ValueMap[I->getOperand(1)];
61 // Unhandled operand. Halt "fast" selection and bail.
64 unsigned ResultReg = FastEmit_rr(VT.getSimpleVT(), VT.getSimpleVT(),
67 // Target-specific code wasn't able to find a machine opcode for
68 // the given ISD opcode and type. Halt "fast" selection and bail.
71 // We successfully emitted code for the given LLVM Instruction.
72 ValueMap[I] = ResultReg;
76 bool FastISel::SelectGetElementPtr(Instruction *I,
77 DenseMap<const Value*, unsigned> &ValueMap) {
78 unsigned N = ValueMap[I->getOperand(0)];
80 // Unhandled operand. Halt "fast" selection and bail.
83 const Type *Ty = I->getOperand(0)->getType();
84 MVT::SimpleValueType VT = TLI.getPointerTy().getSimpleVT();
85 for (GetElementPtrInst::op_iterator OI = I->op_begin()+1, E = I->op_end();
88 if (const StructType *StTy = dyn_cast<StructType>(Ty)) {
89 unsigned Field = cast<ConstantInt>(Idx)->getZExtValue();
92 uint64_t Offs = TD.getStructLayout(StTy)->getElementOffset(Field);
93 // FIXME: This can be optimized by combining the add with a
95 N = FastEmit_ri_(VT, ISD::ADD, N, Offs, VT);
97 // Unhandled operand. Halt "fast" selection and bail.
100 Ty = StTy->getElementType(Field);
102 Ty = cast<SequentialType>(Ty)->getElementType();
104 // If this is a constant subscript, handle it quickly.
105 if (ConstantInt *CI = dyn_cast<ConstantInt>(Idx)) {
106 if (CI->getZExtValue() == 0) continue;
108 TD.getABITypeSize(Ty)*cast<ConstantInt>(CI)->getSExtValue();
109 N = FastEmit_ri_(VT, ISD::ADD, N, Offs, VT);
111 // Unhandled operand. Halt "fast" selection and bail.
116 // N = N + Idx * ElementSize;
117 uint64_t ElementSize = TD.getABITypeSize(Ty);
118 unsigned IdxN = ValueMap[Idx];
120 // Unhandled operand. Halt "fast" selection and bail.
123 // If the index is smaller or larger than intptr_t, truncate or extend
125 MVT IdxVT = MVT::getMVT(Idx->getType(), /*HandleUnknown=*/false);
126 if (IdxVT.bitsLT(VT))
127 IdxN = FastEmit_r(IdxVT.getSimpleVT(), VT, ISD::SIGN_EXTEND, IdxN);
128 else if (IdxVT.bitsGT(VT))
129 IdxN = FastEmit_r(IdxVT.getSimpleVT(), VT, ISD::TRUNCATE, IdxN);
131 // Unhandled operand. Halt "fast" selection and bail.
134 if (ElementSize != 1) {
135 IdxN = FastEmit_ri_(VT, ISD::MUL, IdxN, ElementSize, VT);
137 // Unhandled operand. Halt "fast" selection and bail.
140 N = FastEmit_rr(VT, VT, ISD::ADD, N, IdxN);
142 // Unhandled operand. Halt "fast" selection and bail.
147 // We successfully emitted code for the given LLVM Instruction.
152 bool FastISel::SelectCast(Instruction *I, ISD::NodeType Opcode,
153 DenseMap<const Value*, unsigned> &ValueMap) {
154 MVT SrcVT = MVT::getMVT(I->getOperand(0)->getType());
155 MVT DstVT = MVT::getMVT(I->getType());
157 if (SrcVT == MVT::Other || !SrcVT.isSimple() ||
158 DstVT == MVT::Other || !DstVT.isSimple() ||
159 !TLI.isTypeLegal(SrcVT) || !TLI.isTypeLegal(DstVT))
160 // Unhandled type. Halt "fast" selection and bail.
163 unsigned InputReg = ValueMap[I->getOperand(0)];
165 // Unhandled operand. Halt "fast" selection and bail.
168 unsigned ResultReg = FastEmit_r(SrcVT.getSimpleVT(),
175 ValueMap[I] = ResultReg;
179 bool FastISel::SelectConstantCast(Instruction* I, ISD::NodeType Opcode,
180 DenseMap<const Value*, unsigned> &ValueMap) {
181 // Materialize constant and convert.
182 ConstantInt* CI = cast<ConstantInt>(I->getOperand(0));
183 MVT SrcVT = MVT::getMVT(CI->getType());
184 MVT DstVT = MVT::getMVT(I->getType());
186 if (SrcVT == MVT::Other || !SrcVT.isSimple() ||
187 DstVT == MVT::Other || !DstVT.isSimple() ||
188 !TLI.isTypeLegal(SrcVT) || !TLI.isTypeLegal(DstVT))
189 // Unhandled type. Halt "fast" selection and bail.
192 unsigned ResultReg1 = FastEmit_i(SrcVT.getSimpleVT(),
194 ISD::Constant, CI->getZExtValue());
198 unsigned ResultReg2 = FastEmit_r(SrcVT.getSimpleVT(),
205 ValueMap[I] = ResultReg2;
209 bool FastISel::SelectConstantFPCast(Instruction* I, ISD::NodeType Opcode,
210 DenseMap<const Value*, unsigned> &ValueMap) {
211 // TODO: Implement casting of FP constants by materialization
212 // followed by conversion.
216 bool FastISel::SelectBitCast(Instruction *I,
217 DenseMap<const Value*, unsigned> &ValueMap) {
218 // BitCast consists of either an immediate to register move
219 // or a register to register move.
220 if (ConstantInt* CI = dyn_cast<ConstantInt>(I->getOperand(0))) {
221 if (I->getType()->isInteger()) {
222 MVT VT = MVT::getMVT(I->getType(), /*HandleUnknown=*/false);
223 unsigned result = FastEmit_i(VT.getSimpleVT(), VT.getSimpleVT(),
229 ValueMap[I] = result;
233 // TODO: Support vector and fp constants.
237 if (!isa<Constant>(I->getOperand(0))) {
238 // Bitcasts of non-constant values become reg-reg copies.
239 MVT SrcVT = MVT::getMVT(I->getOperand(0)->getType());
240 MVT DstVT = MVT::getMVT(I->getType());
242 if (SrcVT == MVT::Other || !SrcVT.isSimple() ||
243 DstVT == MVT::Other || !DstVT.isSimple() ||
244 !TLI.isTypeLegal(SrcVT) || !TLI.isTypeLegal(DstVT))
245 // Unhandled type. Halt "fast" selection and bail.
248 unsigned Op0 = ValueMap[I->getOperand(0)];
250 // Unhandled operand. Halt "fast" selection and bail.
253 // First, try to perform the bitcast by inserting a reg-reg copy.
254 unsigned ResultReg = 0;
255 if (SrcVT.getSimpleVT() == DstVT.getSimpleVT()) {
256 TargetRegisterClass* SrcClass = TLI.getRegClassFor(SrcVT);
257 TargetRegisterClass* DstClass = TLI.getRegClassFor(DstVT);
258 ResultReg = createResultReg(DstClass);
260 bool InsertedCopy = TII.copyRegToReg(*MBB, MBB->end(), ResultReg,
261 Op0, DstClass, SrcClass);
266 // If the reg-reg copy failed, select a BIT_CONVERT opcode.
268 ResultReg = FastEmit_r(SrcVT.getSimpleVT(), DstVT.getSimpleVT(),
269 ISD::BIT_CONVERT, Op0);
274 ValueMap[I] = ResultReg;
278 // TODO: Casting a non-integral constant?
283 FastISel::SelectInstructions(BasicBlock::iterator Begin,
284 BasicBlock::iterator End,
285 DenseMap<const Value*, unsigned> &ValueMap,
286 DenseMap<const BasicBlock*,
287 MachineBasicBlock *> &MBBMap,
288 MachineBasicBlock *mbb) {
290 BasicBlock::iterator I = Begin;
292 for (; I != End; ++I) {
293 switch (I->getOpcode()) {
294 case Instruction::Add: {
295 ISD::NodeType Opc = I->getType()->isFPOrFPVector() ? ISD::FADD : ISD::ADD;
296 if (!SelectBinaryOp(I, Opc, ValueMap)) return I; break;
298 case Instruction::Sub: {
299 ISD::NodeType Opc = I->getType()->isFPOrFPVector() ? ISD::FSUB : ISD::SUB;
300 if (!SelectBinaryOp(I, Opc, ValueMap)) return I; break;
302 case Instruction::Mul: {
303 ISD::NodeType Opc = I->getType()->isFPOrFPVector() ? ISD::FMUL : ISD::MUL;
304 if (!SelectBinaryOp(I, Opc, ValueMap)) return I; break;
306 case Instruction::SDiv:
307 if (!SelectBinaryOp(I, ISD::SDIV, ValueMap)) return I; break;
308 case Instruction::UDiv:
309 if (!SelectBinaryOp(I, ISD::UDIV, ValueMap)) return I; break;
310 case Instruction::FDiv:
311 if (!SelectBinaryOp(I, ISD::FDIV, ValueMap)) return I; break;
312 case Instruction::SRem:
313 if (!SelectBinaryOp(I, ISD::SREM, ValueMap)) return I; break;
314 case Instruction::URem:
315 if (!SelectBinaryOp(I, ISD::UREM, ValueMap)) return I; break;
316 case Instruction::FRem:
317 if (!SelectBinaryOp(I, ISD::FREM, ValueMap)) return I; break;
318 case Instruction::Shl:
319 if (!SelectBinaryOp(I, ISD::SHL, ValueMap)) return I; break;
320 case Instruction::LShr:
321 if (!SelectBinaryOp(I, ISD::SRL, ValueMap)) return I; break;
322 case Instruction::AShr:
323 if (!SelectBinaryOp(I, ISD::SRA, ValueMap)) return I; break;
324 case Instruction::And:
325 if (!SelectBinaryOp(I, ISD::AND, ValueMap)) return I; break;
326 case Instruction::Or:
327 if (!SelectBinaryOp(I, ISD::OR, ValueMap)) return I; break;
328 case Instruction::Xor:
329 if (!SelectBinaryOp(I, ISD::XOR, ValueMap)) return I; break;
331 case Instruction::GetElementPtr:
332 if (!SelectGetElementPtr(I, ValueMap)) return I;
335 case Instruction::Br: {
336 BranchInst *BI = cast<BranchInst>(I);
338 if (BI->isUnconditional()) {
339 MachineFunction::iterator NextMBB =
340 next(MachineFunction::iterator(MBB));
341 BasicBlock *LLVMSucc = BI->getSuccessor(0);
342 MachineBasicBlock *MSucc = MBBMap[LLVMSucc];
344 if (NextMBB != MF.end() && MSucc == NextMBB) {
345 // The unconditional fall-through case, which needs no instructions.
347 // The unconditional branch case.
348 TII.InsertBranch(*MBB, MSucc, NULL, SmallVector<MachineOperand, 0>());
350 MBB->addSuccessor(MSucc);
354 // Conditional branches are not handed yet.
355 // Halt "fast" selection and bail.
359 case Instruction::PHI:
360 // PHI nodes are already emitted.
363 case Instruction::BitCast:
364 if (!SelectBitCast(I, ValueMap)) return I; break;
366 case Instruction::FPToSI:
367 if (!isa<ConstantFP>(I->getOperand(0))) {
368 if (!SelectCast(I, ISD::FP_TO_SINT, ValueMap)) return I;
370 if (!SelectConstantFPCast(I, ISD::FP_TO_SINT, ValueMap)) return I;
372 case Instruction::ZExt:
373 if (!isa<ConstantInt>(I->getOperand(0))) {
374 if (!SelectCast(I, ISD::ZERO_EXTEND, ValueMap)) return I;
376 if (!SelectConstantCast(I, ISD::ZERO_EXTEND, ValueMap)) return I;
378 case Instruction::SExt:
379 if (!isa<ConstantInt>(I->getOperand(0))) {
380 if (!SelectCast(I, ISD::SIGN_EXTEND, ValueMap)) return I;
382 if (!SelectConstantCast(I, ISD::SIGN_EXTEND, ValueMap)) return I;
384 case Instruction::SIToFP:
385 if (!isa<ConstantInt>(I->getOperand(0))) {
386 if (!SelectCast(I, ISD::SINT_TO_FP, ValueMap)) return I;
388 if (!SelectConstantCast(I, ISD::SINT_TO_FP, ValueMap)) return I;
391 case Instruction::IntToPtr: // Deliberate fall-through.
392 case Instruction::PtrToInt: {
393 MVT SrcVT = TLI.getValueType(I->getOperand(0)->getType());
394 MVT DstVT = TLI.getValueType(I->getType());
395 if (SrcVT.getSimpleVT() == DstVT.getSimpleVT()) {
396 if (ValueMap[I->getOperand(0)]) {
397 ValueMap[I] = ValueMap[I->getOperand(0)];
402 } else if (DstVT.bitsGT(SrcVT)) {
403 if (!isa<ConstantInt>(I->getOperand(0))) {
404 if (!SelectCast(I, ISD::ZERO_EXTEND, ValueMap)) return I;
406 if (!SelectConstantCast(I, ISD::ZERO_EXTEND, ValueMap)) return I;
409 // TODO: Handle SrcVT > DstVT, where truncation is needed.
415 // Unhandled instruction. Halt "fast" selection and bail.
423 FastISel::FastISel(MachineFunction &mf)
425 MRI(mf.getRegInfo()),
427 TD(*TM.getTargetData()),
428 TII(*TM.getInstrInfo()),
429 TLI(*TM.getTargetLowering()) {
432 FastISel::~FastISel() {}
434 unsigned FastISel::FastEmit_(MVT::SimpleValueType, MVT::SimpleValueType, ISD::NodeType) {
438 unsigned FastISel::FastEmit_r(MVT::SimpleValueType, MVT::SimpleValueType,
439 ISD::NodeType, unsigned /*Op0*/) {
443 unsigned FastISel::FastEmit_rr(MVT::SimpleValueType, MVT::SimpleValueType,
444 ISD::NodeType, unsigned /*Op0*/,
449 unsigned FastISel::FastEmit_i(MVT::SimpleValueType, MVT::SimpleValueType,
450 ISD::NodeType, uint64_t /*Imm*/) {
454 unsigned FastISel::FastEmit_ri(MVT::SimpleValueType, MVT::SimpleValueType,
455 ISD::NodeType, unsigned /*Op0*/,
460 unsigned FastISel::FastEmit_rri(MVT::SimpleValueType, MVT::SimpleValueType,
462 unsigned /*Op0*/, unsigned /*Op1*/,
467 /// FastEmit_ri_ - This method is a wrapper of FastEmit_ri. It first tries
468 /// to emit an instruction with an immediate operand using FastEmit_ri.
469 /// If that fails, it materializes the immediate into a register and try
470 /// FastEmit_rr instead.
471 unsigned FastISel::FastEmit_ri_(MVT::SimpleValueType VT, ISD::NodeType Opcode,
472 unsigned Op0, uint64_t Imm,
473 MVT::SimpleValueType ImmType) {
474 unsigned ResultReg = 0;
475 // First check if immediate type is legal. If not, we can't use the ri form.
476 if (TLI.getOperationAction(ISD::Constant, ImmType) == TargetLowering::Legal)
477 ResultReg = FastEmit_ri(VT, VT, Opcode, Op0, Imm);
480 unsigned MaterialReg = FastEmit_i(ImmType, ImmType, ISD::Constant, Imm);
481 if (MaterialReg == 0)
483 return FastEmit_rr(VT, VT, Opcode, Op0, MaterialReg);
486 unsigned FastISel::createResultReg(const TargetRegisterClass* RC) {
487 return MRI.createVirtualRegister(RC);
490 unsigned FastISel::FastEmitInst_(unsigned MachineInstOpcode,
491 const TargetRegisterClass* RC) {
492 unsigned ResultReg = createResultReg(RC);
493 const TargetInstrDesc &II = TII.get(MachineInstOpcode);
495 BuildMI(MBB, II, ResultReg);
499 unsigned FastISel::FastEmitInst_r(unsigned MachineInstOpcode,
500 const TargetRegisterClass *RC,
502 unsigned ResultReg = createResultReg(RC);
503 const TargetInstrDesc &II = TII.get(MachineInstOpcode);
505 BuildMI(MBB, II, ResultReg).addReg(Op0);
509 unsigned FastISel::FastEmitInst_rr(unsigned MachineInstOpcode,
510 const TargetRegisterClass *RC,
511 unsigned Op0, unsigned Op1) {
512 unsigned ResultReg = createResultReg(RC);
513 const TargetInstrDesc &II = TII.get(MachineInstOpcode);
515 BuildMI(MBB, II, ResultReg).addReg(Op0).addReg(Op1);
519 unsigned FastISel::FastEmitInst_ri(unsigned MachineInstOpcode,
520 const TargetRegisterClass *RC,
521 unsigned Op0, uint64_t Imm) {
522 unsigned ResultReg = createResultReg(RC);
523 const TargetInstrDesc &II = TII.get(MachineInstOpcode);
525 BuildMI(MBB, II, ResultReg).addReg(Op0).addImm(Imm);
529 unsigned FastISel::FastEmitInst_rri(unsigned MachineInstOpcode,
530 const TargetRegisterClass *RC,
531 unsigned Op0, unsigned Op1, uint64_t Imm) {
532 unsigned ResultReg = createResultReg(RC);
533 const TargetInstrDesc &II = TII.get(MachineInstOpcode);
535 BuildMI(MBB, II, ResultReg).addReg(Op0).addReg(Op1).addImm(Imm);
539 unsigned FastISel::FastEmitInst_i(unsigned MachineInstOpcode,
540 const TargetRegisterClass *RC,
542 unsigned ResultReg = createResultReg(RC);
543 const TargetInstrDesc &II = TII.get(MachineInstOpcode);
545 BuildMI(MBB, II, ResultReg).addImm(Imm);