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 // "Fast" instruction selection is designed to emit very poor code quickly.
13 // Also, it is not designed to be able to do much lowering, so most illegal
14 // types (e.g. i64 on 32-bit targets) and operations are not supported. It is
15 // also not intended to be able to do much optimization, except in a few cases
16 // where doing optimizations reduces overall compile time. For example, folding
17 // constants into immediate fields is often done, because it's cheap and it
18 // reduces the number of instructions later phases have to examine.
20 // "Fast" instruction selection is able to fail gracefully and transfer
21 // control to the SelectionDAG selector for operations that it doesn't
22 // support. In many cases, this allows us to avoid duplicating a lot of
23 // the complicated lowering logic that SelectionDAG currently has.
25 // The intended use for "fast" instruction selection is "-O0" mode
26 // compilation, where the quality of the generated code is irrelevant when
27 // weighed against the speed at which the code can be generated. Also,
28 // at -O0, the LLVM optimizers are not running, and this makes the
29 // compile time of codegen a much higher portion of the overall compile
30 // time. Despite its limitations, "fast" instruction selection is able to
31 // handle enough code on its own to provide noticeable overall speedups
34 // Basic operations are supported in a target-independent way, by reading
35 // the same instruction descriptions that the SelectionDAG selector reads,
36 // and identifying simple arithmetic operations that can be directly selected
37 // from simple operators. More complicated operations currently require
38 // target-specific code.
40 //===----------------------------------------------------------------------===//
42 #define DEBUG_TYPE "isel"
43 #include "llvm/Function.h"
44 #include "llvm/GlobalVariable.h"
45 #include "llvm/Instructions.h"
46 #include "llvm/IntrinsicInst.h"
47 #include "llvm/Operator.h"
48 #include "llvm/CodeGen/Analysis.h"
49 #include "llvm/CodeGen/FastISel.h"
50 #include "llvm/CodeGen/FunctionLoweringInfo.h"
51 #include "llvm/CodeGen/MachineInstrBuilder.h"
52 #include "llvm/CodeGen/MachineModuleInfo.h"
53 #include "llvm/CodeGen/MachineRegisterInfo.h"
54 #include "llvm/Analysis/DebugInfo.h"
55 #include "llvm/Analysis/Loads.h"
56 #include "llvm/Target/TargetData.h"
57 #include "llvm/Target/TargetInstrInfo.h"
58 #include "llvm/Target/TargetLowering.h"
59 #include "llvm/Target/TargetMachine.h"
60 #include "llvm/Support/ErrorHandling.h"
61 #include "llvm/Support/Debug.h"
62 #include "llvm/ADT/Statistic.h"
65 STATISTIC(NumFastIselSuccessIndependent, "Number of insts selected by "
66 "target-independent selector");
67 STATISTIC(NumFastIselSuccessTarget, "Number of insts selected by "
68 "target-specific selector");
69 STATISTIC(NumFastIselDead, "Number of dead insts removed on failure");
71 /// startNewBlock - Set the current block to which generated machine
72 /// instructions will be appended, and clear the local CSE map.
74 void FastISel::startNewBlock() {
75 LocalValueMap.clear();
79 // Advance the emit start point past any EH_LABEL instructions.
80 MachineBasicBlock::iterator
81 I = FuncInfo.MBB->begin(), E = FuncInfo.MBB->end();
82 while (I != E && I->getOpcode() == TargetOpcode::EH_LABEL) {
86 LastLocalValue = EmitStartPt;
89 void FastISel::flushLocalValueMap() {
90 LocalValueMap.clear();
91 LastLocalValue = EmitStartPt;
95 bool FastISel::hasTrivialKill(const Value *V) const {
96 // Don't consider constants or arguments to have trivial kills.
97 const Instruction *I = dyn_cast<Instruction>(V);
101 // No-op casts are trivially coalesced by fast-isel.
102 if (const CastInst *Cast = dyn_cast<CastInst>(I))
103 if (Cast->isNoopCast(TD.getIntPtrType(Cast->getContext())) &&
104 !hasTrivialKill(Cast->getOperand(0)))
107 // GEPs with all zero indices are trivially coalesced by fast-isel.
108 if (const GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(I))
109 if (GEP->hasAllZeroIndices() && !hasTrivialKill(GEP->getOperand(0)))
112 // Only instructions with a single use in the same basic block are considered
113 // to have trivial kills.
114 return I->hasOneUse() &&
115 !(I->getOpcode() == Instruction::BitCast ||
116 I->getOpcode() == Instruction::PtrToInt ||
117 I->getOpcode() == Instruction::IntToPtr) &&
118 cast<Instruction>(*I->use_begin())->getParent() == I->getParent();
121 unsigned FastISel::getRegForValue(const Value *V) {
122 EVT RealVT = TLI.getValueType(V->getType(), /*AllowUnknown=*/true);
123 // Don't handle non-simple values in FastISel.
124 if (!RealVT.isSimple())
127 // Ignore illegal types. We must do this before looking up the value
128 // in ValueMap because Arguments are given virtual registers regardless
129 // of whether FastISel can handle them.
130 MVT VT = RealVT.getSimpleVT();
131 if (!TLI.isTypeLegal(VT)) {
132 // Handle integer promotions, though, because they're common and easy.
133 if (VT == MVT::i1 || VT == MVT::i8 || VT == MVT::i16)
134 VT = TLI.getTypeToTransformTo(V->getContext(), VT).getSimpleVT();
139 // Look up the value to see if we already have a register for it.
140 unsigned Reg = lookUpRegForValue(V);
144 // In bottom-up mode, just create the virtual register which will be used
145 // to hold the value. It will be materialized later.
146 if (isa<Instruction>(V) &&
147 (!isa<AllocaInst>(V) ||
148 !FuncInfo.StaticAllocaMap.count(cast<AllocaInst>(V))))
149 return FuncInfo.InitializeRegForValue(V);
151 SavePoint SaveInsertPt = enterLocalValueArea();
153 // Materialize the value in a register. Emit any instructions in the
155 Reg = materializeRegForValue(V, VT);
157 leaveLocalValueArea(SaveInsertPt);
162 /// materializeRegForValue - Helper for getRegForValue. This function is
163 /// called when the value isn't already available in a register and must
164 /// be materialized with new instructions.
165 unsigned FastISel::materializeRegForValue(const Value *V, MVT VT) {
168 if (const ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
169 if (CI->getValue().getActiveBits() <= 64)
170 Reg = FastEmit_i(VT, VT, ISD::Constant, CI->getZExtValue());
171 } else if (isa<AllocaInst>(V)) {
172 Reg = TargetMaterializeAlloca(cast<AllocaInst>(V));
173 } else if (isa<ConstantPointerNull>(V)) {
174 // Translate this as an integer zero so that it can be
175 // local-CSE'd with actual integer zeros.
177 getRegForValue(Constant::getNullValue(TD.getIntPtrType(V->getContext())));
178 } else if (const ConstantFP *CF = dyn_cast<ConstantFP>(V)) {
179 if (CF->isNullValue()) {
180 Reg = TargetMaterializeFloatZero(CF);
182 // Try to emit the constant directly.
183 Reg = FastEmit_f(VT, VT, ISD::ConstantFP, CF);
187 // Try to emit the constant by using an integer constant with a cast.
188 const APFloat &Flt = CF->getValueAPF();
189 EVT IntVT = TLI.getPointerTy();
192 uint32_t IntBitWidth = IntVT.getSizeInBits();
194 (void) Flt.convertToInteger(x, IntBitWidth, /*isSigned=*/true,
195 APFloat::rmTowardZero, &isExact);
197 APInt IntVal(IntBitWidth, x);
199 unsigned IntegerReg =
200 getRegForValue(ConstantInt::get(V->getContext(), IntVal));
202 Reg = FastEmit_r(IntVT.getSimpleVT(), VT, ISD::SINT_TO_FP,
203 IntegerReg, /*Kill=*/false);
206 } else if (const Operator *Op = dyn_cast<Operator>(V)) {
207 if (!SelectOperator(Op, Op->getOpcode()))
208 if (!isa<Instruction>(Op) ||
209 !TargetSelectInstruction(cast<Instruction>(Op)))
211 Reg = lookUpRegForValue(Op);
212 } else if (isa<UndefValue>(V)) {
213 Reg = createResultReg(TLI.getRegClassFor(VT));
214 BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL,
215 TII.get(TargetOpcode::IMPLICIT_DEF), Reg);
218 // If target-independent code couldn't handle the value, give target-specific
220 if (!Reg && isa<Constant>(V))
221 Reg = TargetMaterializeConstant(cast<Constant>(V));
223 // Don't cache constant materializations in the general ValueMap.
224 // To do so would require tracking what uses they dominate.
226 LocalValueMap[V] = Reg;
227 LastLocalValue = MRI.getVRegDef(Reg);
232 unsigned FastISel::lookUpRegForValue(const Value *V) {
233 // Look up the value to see if we already have a register for it. We
234 // cache values defined by Instructions across blocks, and other values
235 // only locally. This is because Instructions already have the SSA
236 // def-dominates-use requirement enforced.
237 DenseMap<const Value *, unsigned>::iterator I = FuncInfo.ValueMap.find(V);
238 if (I != FuncInfo.ValueMap.end())
240 return LocalValueMap[V];
243 /// UpdateValueMap - Update the value map to include the new mapping for this
244 /// instruction, or insert an extra copy to get the result in a previous
245 /// determined register.
246 /// NOTE: This is only necessary because we might select a block that uses
247 /// a value before we select the block that defines the value. It might be
248 /// possible to fix this by selecting blocks in reverse postorder.
249 void FastISel::UpdateValueMap(const Value *I, unsigned Reg, unsigned NumRegs) {
250 if (!isa<Instruction>(I)) {
251 LocalValueMap[I] = Reg;
255 unsigned &AssignedReg = FuncInfo.ValueMap[I];
256 if (AssignedReg == 0)
257 // Use the new register.
259 else if (Reg != AssignedReg) {
260 // Arrange for uses of AssignedReg to be replaced by uses of Reg.
261 for (unsigned i = 0; i < NumRegs; i++)
262 FuncInfo.RegFixups[AssignedReg+i] = Reg+i;
268 std::pair<unsigned, bool> FastISel::getRegForGEPIndex(const Value *Idx) {
269 unsigned IdxN = getRegForValue(Idx);
271 // Unhandled operand. Halt "fast" selection and bail.
272 return std::pair<unsigned, bool>(0, false);
274 bool IdxNIsKill = hasTrivialKill(Idx);
276 // If the index is smaller or larger than intptr_t, truncate or extend it.
277 MVT PtrVT = TLI.getPointerTy();
278 EVT IdxVT = EVT::getEVT(Idx->getType(), /*HandleUnknown=*/false);
279 if (IdxVT.bitsLT(PtrVT)) {
280 IdxN = FastEmit_r(IdxVT.getSimpleVT(), PtrVT, ISD::SIGN_EXTEND,
284 else if (IdxVT.bitsGT(PtrVT)) {
285 IdxN = FastEmit_r(IdxVT.getSimpleVT(), PtrVT, ISD::TRUNCATE,
289 return std::pair<unsigned, bool>(IdxN, IdxNIsKill);
292 void FastISel::recomputeInsertPt() {
293 if (getLastLocalValue()) {
294 FuncInfo.InsertPt = getLastLocalValue();
295 FuncInfo.MBB = FuncInfo.InsertPt->getParent();
298 FuncInfo.InsertPt = FuncInfo.MBB->getFirstNonPHI();
300 // Now skip past any EH_LABELs, which must remain at the beginning.
301 while (FuncInfo.InsertPt != FuncInfo.MBB->end() &&
302 FuncInfo.InsertPt->getOpcode() == TargetOpcode::EH_LABEL)
306 void FastISel::removeDeadCode(MachineBasicBlock::iterator I,
307 MachineBasicBlock::iterator E) {
308 assert (I && E && std::distance(I, E) > 0 && "Invalid iterator!");
310 MachineInstr *Dead = &*I;
312 Dead->eraseFromParent();
318 FastISel::SavePoint FastISel::enterLocalValueArea() {
319 MachineBasicBlock::iterator OldInsertPt = FuncInfo.InsertPt;
323 SavePoint SP = { OldInsertPt, OldDL };
327 void FastISel::leaveLocalValueArea(SavePoint OldInsertPt) {
328 if (FuncInfo.InsertPt != FuncInfo.MBB->begin())
329 LastLocalValue = llvm::prior(FuncInfo.InsertPt);
331 // Restore the previous insert position.
332 FuncInfo.InsertPt = OldInsertPt.InsertPt;
336 /// SelectBinaryOp - Select and emit code for a binary operator instruction,
337 /// which has an opcode which directly corresponds to the given ISD opcode.
339 bool FastISel::SelectBinaryOp(const User *I, unsigned ISDOpcode) {
340 EVT VT = EVT::getEVT(I->getType(), /*HandleUnknown=*/true);
341 if (VT == MVT::Other || !VT.isSimple())
342 // Unhandled type. Halt "fast" selection and bail.
345 // We only handle legal types. For example, on x86-32 the instruction
346 // selector contains all of the 64-bit instructions from x86-64,
347 // under the assumption that i64 won't be used if the target doesn't
349 if (!TLI.isTypeLegal(VT)) {
350 // MVT::i1 is special. Allow AND, OR, or XOR because they
351 // don't require additional zeroing, which makes them easy.
353 (ISDOpcode == ISD::AND || ISDOpcode == ISD::OR ||
354 ISDOpcode == ISD::XOR))
355 VT = TLI.getTypeToTransformTo(I->getContext(), VT);
360 // Check if the first operand is a constant, and handle it as "ri". At -O0,
361 // we don't have anything that canonicalizes operand order.
362 if (ConstantInt *CI = dyn_cast<ConstantInt>(I->getOperand(0)))
363 if (isa<Instruction>(I) && cast<Instruction>(I)->isCommutative()) {
364 unsigned Op1 = getRegForValue(I->getOperand(1));
365 if (Op1 == 0) return false;
367 bool Op1IsKill = hasTrivialKill(I->getOperand(1));
369 unsigned ResultReg = FastEmit_ri_(VT.getSimpleVT(), ISDOpcode, Op1,
370 Op1IsKill, CI->getZExtValue(),
372 if (ResultReg == 0) return false;
374 // We successfully emitted code for the given LLVM Instruction.
375 UpdateValueMap(I, ResultReg);
380 unsigned Op0 = getRegForValue(I->getOperand(0));
381 if (Op0 == 0) // Unhandled operand. Halt "fast" selection and bail.
384 bool Op0IsKill = hasTrivialKill(I->getOperand(0));
386 // Check if the second operand is a constant and handle it appropriately.
387 if (ConstantInt *CI = dyn_cast<ConstantInt>(I->getOperand(1))) {
388 uint64_t Imm = CI->getZExtValue();
390 // Transform "sdiv exact X, 8" -> "sra X, 3".
391 if (ISDOpcode == ISD::SDIV && isa<BinaryOperator>(I) &&
392 cast<BinaryOperator>(I)->isExact() &&
393 isPowerOf2_64(Imm)) {
395 ISDOpcode = ISD::SRA;
398 unsigned ResultReg = FastEmit_ri_(VT.getSimpleVT(), ISDOpcode, Op0,
399 Op0IsKill, Imm, VT.getSimpleVT());
400 if (ResultReg == 0) return false;
402 // We successfully emitted code for the given LLVM Instruction.
403 UpdateValueMap(I, ResultReg);
407 // Check if the second operand is a constant float.
408 if (ConstantFP *CF = dyn_cast<ConstantFP>(I->getOperand(1))) {
409 unsigned ResultReg = FastEmit_rf(VT.getSimpleVT(), VT.getSimpleVT(),
410 ISDOpcode, Op0, Op0IsKill, CF);
411 if (ResultReg != 0) {
412 // We successfully emitted code for the given LLVM Instruction.
413 UpdateValueMap(I, ResultReg);
418 unsigned Op1 = getRegForValue(I->getOperand(1));
420 // Unhandled operand. Halt "fast" selection and bail.
423 bool Op1IsKill = hasTrivialKill(I->getOperand(1));
425 // Now we have both operands in registers. Emit the instruction.
426 unsigned ResultReg = FastEmit_rr(VT.getSimpleVT(), VT.getSimpleVT(),
431 // Target-specific code wasn't able to find a machine opcode for
432 // the given ISD opcode and type. Halt "fast" selection and bail.
435 // We successfully emitted code for the given LLVM Instruction.
436 UpdateValueMap(I, ResultReg);
440 bool FastISel::SelectGetElementPtr(const User *I) {
441 unsigned N = getRegForValue(I->getOperand(0));
443 // Unhandled operand. Halt "fast" selection and bail.
446 bool NIsKill = hasTrivialKill(I->getOperand(0));
448 // Keep a running tab of the total offset to coalesce multiple N = N + Offset
449 // into a single N = N + TotalOffset.
450 uint64_t TotalOffs = 0;
451 // FIXME: What's a good SWAG number for MaxOffs?
452 uint64_t MaxOffs = 2048;
453 Type *Ty = I->getOperand(0)->getType();
454 MVT VT = TLI.getPointerTy();
455 for (GetElementPtrInst::const_op_iterator OI = I->op_begin()+1,
456 E = I->op_end(); OI != E; ++OI) {
457 const Value *Idx = *OI;
458 if (StructType *StTy = dyn_cast<StructType>(Ty)) {
459 unsigned Field = cast<ConstantInt>(Idx)->getZExtValue();
462 TotalOffs += TD.getStructLayout(StTy)->getElementOffset(Field);
463 if (TotalOffs >= MaxOffs) {
464 N = FastEmit_ri_(VT, ISD::ADD, N, NIsKill, TotalOffs, VT);
466 // Unhandled operand. Halt "fast" selection and bail.
472 Ty = StTy->getElementType(Field);
474 Ty = cast<SequentialType>(Ty)->getElementType();
476 // If this is a constant subscript, handle it quickly.
477 if (const ConstantInt *CI = dyn_cast<ConstantInt>(Idx)) {
478 if (CI->isZero()) continue;
481 TD.getTypeAllocSize(Ty)*cast<ConstantInt>(CI)->getSExtValue();
482 if (TotalOffs >= MaxOffs) {
483 N = FastEmit_ri_(VT, ISD::ADD, N, NIsKill, TotalOffs, VT);
485 // Unhandled operand. Halt "fast" selection and bail.
493 N = FastEmit_ri_(VT, ISD::ADD, N, NIsKill, TotalOffs, VT);
495 // Unhandled operand. Halt "fast" selection and bail.
501 // N = N + Idx * ElementSize;
502 uint64_t ElementSize = TD.getTypeAllocSize(Ty);
503 std::pair<unsigned, bool> Pair = getRegForGEPIndex(Idx);
504 unsigned IdxN = Pair.first;
505 bool IdxNIsKill = Pair.second;
507 // Unhandled operand. Halt "fast" selection and bail.
510 if (ElementSize != 1) {
511 IdxN = FastEmit_ri_(VT, ISD::MUL, IdxN, IdxNIsKill, ElementSize, VT);
513 // Unhandled operand. Halt "fast" selection and bail.
517 N = FastEmit_rr(VT, VT, ISD::ADD, N, NIsKill, IdxN, IdxNIsKill);
519 // Unhandled operand. Halt "fast" selection and bail.
524 N = FastEmit_ri_(VT, ISD::ADD, N, NIsKill, TotalOffs, VT);
526 // Unhandled operand. Halt "fast" selection and bail.
530 // We successfully emitted code for the given LLVM Instruction.
531 UpdateValueMap(I, N);
535 bool FastISel::SelectCall(const User *I) {
536 const CallInst *Call = cast<CallInst>(I);
538 // Handle simple inline asms.
539 if (const InlineAsm *IA = dyn_cast<InlineAsm>(Call->getCalledValue())) {
540 // Don't attempt to handle constraints.
541 if (!IA->getConstraintString().empty())
544 unsigned ExtraInfo = 0;
545 if (IA->hasSideEffects())
546 ExtraInfo |= InlineAsm::Extra_HasSideEffects;
547 if (IA->isAlignStack())
548 ExtraInfo |= InlineAsm::Extra_IsAlignStack;
550 BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL,
551 TII.get(TargetOpcode::INLINEASM))
552 .addExternalSymbol(IA->getAsmString().c_str())
557 MachineModuleInfo &MMI = FuncInfo.MF->getMMI();
558 ComputeUsesVAFloatArgument(*Call, &MMI);
560 const Function *F = Call->getCalledFunction();
561 if (!F) return false;
563 // Handle selected intrinsic function calls.
564 switch (F->getIntrinsicID()) {
566 // At -O0 we don't care about the lifetime intrinsics.
567 case Intrinsic::lifetime_start:
568 case Intrinsic::lifetime_end:
570 case Intrinsic::dbg_declare: {
571 const DbgDeclareInst *DI = cast<DbgDeclareInst>(Call);
572 if (!DIVariable(DI->getVariable()).Verify() ||
573 !FuncInfo.MF->getMMI().hasDebugInfo()) {
574 DEBUG(dbgs() << "Dropping debug info for " << *DI << "\n");
578 const Value *Address = DI->getAddress();
579 if (!Address || isa<UndefValue>(Address)) {
580 DEBUG(dbgs() << "Dropping debug info for " << *DI << "\n");
586 if (const Argument *Arg = dyn_cast<Argument>(Address)) {
587 // Some arguments' frame index is recorded during argument lowering.
588 Offset = FuncInfo.getArgumentFrameIndex(Arg);
590 Reg = TRI.getFrameRegister(*FuncInfo.MF);
593 Reg = lookUpRegForValue(Address);
595 if (!Reg && isa<Instruction>(Address) &&
596 (!isa<AllocaInst>(Address) ||
597 !FuncInfo.StaticAllocaMap.count(cast<AllocaInst>(Address))))
598 Reg = FuncInfo.InitializeRegForValue(Address);
601 BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL,
602 TII.get(TargetOpcode::DBG_VALUE))
603 .addReg(Reg, RegState::Debug).addImm(Offset)
604 .addMetadata(DI->getVariable());
606 // We can't yet handle anything else here because it would require
607 // generating code, thus altering codegen because of debug info.
608 DEBUG(dbgs() << "Dropping debug info for " << DI);
611 case Intrinsic::dbg_value: {
612 // This form of DBG_VALUE is target-independent.
613 const DbgValueInst *DI = cast<DbgValueInst>(Call);
614 const MCInstrDesc &II = TII.get(TargetOpcode::DBG_VALUE);
615 const Value *V = DI->getValue();
617 // Currently the optimizer can produce this; insert an undef to
618 // help debugging. Probably the optimizer should not do this.
619 BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL, II)
620 .addReg(0U).addImm(DI->getOffset())
621 .addMetadata(DI->getVariable());
622 } else if (const ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
623 if (CI->getBitWidth() > 64)
624 BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL, II)
625 .addCImm(CI).addImm(DI->getOffset())
626 .addMetadata(DI->getVariable());
628 BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL, II)
629 .addImm(CI->getZExtValue()).addImm(DI->getOffset())
630 .addMetadata(DI->getVariable());
631 } else if (const ConstantFP *CF = dyn_cast<ConstantFP>(V)) {
632 BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL, II)
633 .addFPImm(CF).addImm(DI->getOffset())
634 .addMetadata(DI->getVariable());
635 } else if (unsigned Reg = lookUpRegForValue(V)) {
636 BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL, II)
637 .addReg(Reg, RegState::Debug).addImm(DI->getOffset())
638 .addMetadata(DI->getVariable());
640 // We can't yet handle anything else here because it would require
641 // generating code, thus altering codegen because of debug info.
642 DEBUG(dbgs() << "Dropping debug info for " << DI);
646 case Intrinsic::objectsize: {
647 ConstantInt *CI = cast<ConstantInt>(Call->getArgOperand(1));
648 unsigned long long Res = CI->isZero() ? -1ULL : 0;
649 Constant *ResCI = ConstantInt::get(Call->getType(), Res);
650 unsigned ResultReg = getRegForValue(ResCI);
653 UpdateValueMap(Call, ResultReg);
658 // Usually, it does not make sense to initialize a value,
659 // make an unrelated function call and use the value, because
660 // it tends to be spilled on the stack. So, we move the pointer
661 // to the last local value to the beginning of the block, so that
662 // all the values which have already been materialized,
663 // appear after the call. It also makes sense to skip intrinsics
664 // since they tend to be inlined.
665 if (!isa<IntrinsicInst>(F))
666 flushLocalValueMap();
668 // An arbitrary call. Bail.
672 bool FastISel::SelectCast(const User *I, unsigned Opcode) {
673 EVT SrcVT = TLI.getValueType(I->getOperand(0)->getType());
674 EVT DstVT = TLI.getValueType(I->getType());
676 if (SrcVT == MVT::Other || !SrcVT.isSimple() ||
677 DstVT == MVT::Other || !DstVT.isSimple())
678 // Unhandled type. Halt "fast" selection and bail.
681 // Check if the destination type is legal.
682 if (!TLI.isTypeLegal(DstVT))
685 // Check if the source operand is legal.
686 if (!TLI.isTypeLegal(SrcVT))
689 unsigned InputReg = getRegForValue(I->getOperand(0));
691 // Unhandled operand. Halt "fast" selection and bail.
694 bool InputRegIsKill = hasTrivialKill(I->getOperand(0));
696 unsigned ResultReg = FastEmit_r(SrcVT.getSimpleVT(),
699 InputReg, InputRegIsKill);
703 UpdateValueMap(I, ResultReg);
707 bool FastISel::SelectBitCast(const User *I) {
708 // If the bitcast doesn't change the type, just use the operand value.
709 if (I->getType() == I->getOperand(0)->getType()) {
710 unsigned Reg = getRegForValue(I->getOperand(0));
713 UpdateValueMap(I, Reg);
717 // Bitcasts of other values become reg-reg copies or BITCAST operators.
718 EVT SrcVT = TLI.getValueType(I->getOperand(0)->getType());
719 EVT DstVT = TLI.getValueType(I->getType());
721 if (SrcVT == MVT::Other || !SrcVT.isSimple() ||
722 DstVT == MVT::Other || !DstVT.isSimple() ||
723 !TLI.isTypeLegal(SrcVT) || !TLI.isTypeLegal(DstVT))
724 // Unhandled type. Halt "fast" selection and bail.
727 unsigned Op0 = getRegForValue(I->getOperand(0));
729 // Unhandled operand. Halt "fast" selection and bail.
732 bool Op0IsKill = hasTrivialKill(I->getOperand(0));
734 // First, try to perform the bitcast by inserting a reg-reg copy.
735 unsigned ResultReg = 0;
736 if (SrcVT.getSimpleVT() == DstVT.getSimpleVT()) {
737 const TargetRegisterClass* SrcClass = TLI.getRegClassFor(SrcVT);
738 const TargetRegisterClass* DstClass = TLI.getRegClassFor(DstVT);
739 // Don't attempt a cross-class copy. It will likely fail.
740 if (SrcClass == DstClass) {
741 ResultReg = createResultReg(DstClass);
742 BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL, TII.get(TargetOpcode::COPY),
743 ResultReg).addReg(Op0);
747 // If the reg-reg copy failed, select a BITCAST opcode.
749 ResultReg = FastEmit_r(SrcVT.getSimpleVT(), DstVT.getSimpleVT(),
750 ISD::BITCAST, Op0, Op0IsKill);
755 UpdateValueMap(I, ResultReg);
760 FastISel::SelectInstruction(const Instruction *I) {
761 // Just before the terminator instruction, insert instructions to
762 // feed PHI nodes in successor blocks.
763 if (isa<TerminatorInst>(I))
764 if (!HandlePHINodesInSuccessorBlocks(I->getParent()))
767 DL = I->getDebugLoc();
769 MachineBasicBlock::iterator SavedInsertPt = FuncInfo.InsertPt;
771 // First, try doing target-independent selection.
772 if (SelectOperator(I, I->getOpcode())) {
773 ++NumFastIselSuccessIndependent;
777 // Remove dead code. However, ignore call instructions since we've flushed
778 // the local value map and recomputed the insert point.
779 if (!isa<CallInst>(I)) {
781 if (SavedInsertPt != FuncInfo.InsertPt)
782 removeDeadCode(FuncInfo.InsertPt, SavedInsertPt);
785 // Next, try calling the target to attempt to handle the instruction.
786 SavedInsertPt = FuncInfo.InsertPt;
787 if (TargetSelectInstruction(I)) {
788 ++NumFastIselSuccessTarget;
792 // Check for dead code and remove as necessary.
794 if (SavedInsertPt != FuncInfo.InsertPt)
795 removeDeadCode(FuncInfo.InsertPt, SavedInsertPt);
801 /// FastEmitBranch - Emit an unconditional branch to the given block,
802 /// unless it is the immediate (fall-through) successor, and update
805 FastISel::FastEmitBranch(MachineBasicBlock *MSucc, DebugLoc DL) {
806 if (FuncInfo.MBB->isLayoutSuccessor(MSucc)) {
807 // The unconditional fall-through case, which needs no instructions.
809 // The unconditional branch case.
810 TII.InsertBranch(*FuncInfo.MBB, MSucc, NULL,
811 SmallVector<MachineOperand, 0>(), DL);
813 FuncInfo.MBB->addSuccessor(MSucc);
816 /// SelectFNeg - Emit an FNeg operation.
819 FastISel::SelectFNeg(const User *I) {
820 unsigned OpReg = getRegForValue(BinaryOperator::getFNegArgument(I));
821 if (OpReg == 0) return false;
823 bool OpRegIsKill = hasTrivialKill(I);
825 // If the target has ISD::FNEG, use it.
826 EVT VT = TLI.getValueType(I->getType());
827 unsigned ResultReg = FastEmit_r(VT.getSimpleVT(), VT.getSimpleVT(),
828 ISD::FNEG, OpReg, OpRegIsKill);
829 if (ResultReg != 0) {
830 UpdateValueMap(I, ResultReg);
834 // Bitcast the value to integer, twiddle the sign bit with xor,
835 // and then bitcast it back to floating-point.
836 if (VT.getSizeInBits() > 64) return false;
837 EVT IntVT = EVT::getIntegerVT(I->getContext(), VT.getSizeInBits());
838 if (!TLI.isTypeLegal(IntVT))
841 unsigned IntReg = FastEmit_r(VT.getSimpleVT(), IntVT.getSimpleVT(),
842 ISD::BITCAST, OpReg, OpRegIsKill);
846 unsigned IntResultReg = FastEmit_ri_(IntVT.getSimpleVT(), ISD::XOR,
847 IntReg, /*Kill=*/true,
848 UINT64_C(1) << (VT.getSizeInBits()-1),
849 IntVT.getSimpleVT());
850 if (IntResultReg == 0)
853 ResultReg = FastEmit_r(IntVT.getSimpleVT(), VT.getSimpleVT(),
854 ISD::BITCAST, IntResultReg, /*Kill=*/true);
858 UpdateValueMap(I, ResultReg);
863 FastISel::SelectExtractValue(const User *U) {
864 const ExtractValueInst *EVI = dyn_cast<ExtractValueInst>(U);
868 // Make sure we only try to handle extracts with a legal result. But also
869 // allow i1 because it's easy.
870 EVT RealVT = TLI.getValueType(EVI->getType(), /*AllowUnknown=*/true);
871 if (!RealVT.isSimple())
873 MVT VT = RealVT.getSimpleVT();
874 if (!TLI.isTypeLegal(VT) && VT != MVT::i1)
877 const Value *Op0 = EVI->getOperand(0);
878 Type *AggTy = Op0->getType();
880 // Get the base result register.
882 DenseMap<const Value *, unsigned>::iterator I = FuncInfo.ValueMap.find(Op0);
883 if (I != FuncInfo.ValueMap.end())
884 ResultReg = I->second;
885 else if (isa<Instruction>(Op0))
886 ResultReg = FuncInfo.InitializeRegForValue(Op0);
888 return false; // fast-isel can't handle aggregate constants at the moment
890 // Get the actual result register, which is an offset from the base register.
891 unsigned VTIndex = ComputeLinearIndex(AggTy, EVI->getIndices());
893 SmallVector<EVT, 4> AggValueVTs;
894 ComputeValueVTs(TLI, AggTy, AggValueVTs);
896 for (unsigned i = 0; i < VTIndex; i++)
897 ResultReg += TLI.getNumRegisters(FuncInfo.Fn->getContext(), AggValueVTs[i]);
899 UpdateValueMap(EVI, ResultReg);
904 FastISel::SelectOperator(const User *I, unsigned Opcode) {
906 case Instruction::Add:
907 return SelectBinaryOp(I, ISD::ADD);
908 case Instruction::FAdd:
909 return SelectBinaryOp(I, ISD::FADD);
910 case Instruction::Sub:
911 return SelectBinaryOp(I, ISD::SUB);
912 case Instruction::FSub:
913 // FNeg is currently represented in LLVM IR as a special case of FSub.
914 if (BinaryOperator::isFNeg(I))
915 return SelectFNeg(I);
916 return SelectBinaryOp(I, ISD::FSUB);
917 case Instruction::Mul:
918 return SelectBinaryOp(I, ISD::MUL);
919 case Instruction::FMul:
920 return SelectBinaryOp(I, ISD::FMUL);
921 case Instruction::SDiv:
922 return SelectBinaryOp(I, ISD::SDIV);
923 case Instruction::UDiv:
924 return SelectBinaryOp(I, ISD::UDIV);
925 case Instruction::FDiv:
926 return SelectBinaryOp(I, ISD::FDIV);
927 case Instruction::SRem:
928 return SelectBinaryOp(I, ISD::SREM);
929 case Instruction::URem:
930 return SelectBinaryOp(I, ISD::UREM);
931 case Instruction::FRem:
932 return SelectBinaryOp(I, ISD::FREM);
933 case Instruction::Shl:
934 return SelectBinaryOp(I, ISD::SHL);
935 case Instruction::LShr:
936 return SelectBinaryOp(I, ISD::SRL);
937 case Instruction::AShr:
938 return SelectBinaryOp(I, ISD::SRA);
939 case Instruction::And:
940 return SelectBinaryOp(I, ISD::AND);
941 case Instruction::Or:
942 return SelectBinaryOp(I, ISD::OR);
943 case Instruction::Xor:
944 return SelectBinaryOp(I, ISD::XOR);
946 case Instruction::GetElementPtr:
947 return SelectGetElementPtr(I);
949 case Instruction::Br: {
950 const BranchInst *BI = cast<BranchInst>(I);
952 if (BI->isUnconditional()) {
953 const BasicBlock *LLVMSucc = BI->getSuccessor(0);
954 MachineBasicBlock *MSucc = FuncInfo.MBBMap[LLVMSucc];
955 FastEmitBranch(MSucc, BI->getDebugLoc());
959 // Conditional branches are not handed yet.
960 // Halt "fast" selection and bail.
964 case Instruction::Unreachable:
968 case Instruction::Alloca:
969 // FunctionLowering has the static-sized case covered.
970 if (FuncInfo.StaticAllocaMap.count(cast<AllocaInst>(I)))
973 // Dynamic-sized alloca is not handled yet.
976 case Instruction::Call:
977 return SelectCall(I);
979 case Instruction::BitCast:
980 return SelectBitCast(I);
982 case Instruction::FPToSI:
983 return SelectCast(I, ISD::FP_TO_SINT);
984 case Instruction::ZExt:
985 return SelectCast(I, ISD::ZERO_EXTEND);
986 case Instruction::SExt:
987 return SelectCast(I, ISD::SIGN_EXTEND);
988 case Instruction::Trunc:
989 return SelectCast(I, ISD::TRUNCATE);
990 case Instruction::SIToFP:
991 return SelectCast(I, ISD::SINT_TO_FP);
993 case Instruction::IntToPtr: // Deliberate fall-through.
994 case Instruction::PtrToInt: {
995 EVT SrcVT = TLI.getValueType(I->getOperand(0)->getType());
996 EVT DstVT = TLI.getValueType(I->getType());
997 if (DstVT.bitsGT(SrcVT))
998 return SelectCast(I, ISD::ZERO_EXTEND);
999 if (DstVT.bitsLT(SrcVT))
1000 return SelectCast(I, ISD::TRUNCATE);
1001 unsigned Reg = getRegForValue(I->getOperand(0));
1002 if (Reg == 0) return false;
1003 UpdateValueMap(I, Reg);
1007 case Instruction::ExtractValue:
1008 return SelectExtractValue(I);
1010 case Instruction::PHI:
1011 llvm_unreachable("FastISel shouldn't visit PHI nodes!");
1014 // Unhandled instruction. Halt "fast" selection and bail.
1019 FastISel::FastISel(FunctionLoweringInfo &funcInfo)
1020 : FuncInfo(funcInfo),
1021 MRI(FuncInfo.MF->getRegInfo()),
1022 MFI(*FuncInfo.MF->getFrameInfo()),
1023 MCP(*FuncInfo.MF->getConstantPool()),
1024 TM(FuncInfo.MF->getTarget()),
1025 TD(*TM.getTargetData()),
1026 TII(*TM.getInstrInfo()),
1027 TLI(*TM.getTargetLowering()),
1028 TRI(*TM.getRegisterInfo()) {
1031 FastISel::~FastISel() {}
1033 unsigned FastISel::FastEmit_(MVT, MVT,
1038 unsigned FastISel::FastEmit_r(MVT, MVT,
1040 unsigned /*Op0*/, bool /*Op0IsKill*/) {
1044 unsigned FastISel::FastEmit_rr(MVT, MVT,
1046 unsigned /*Op0*/, bool /*Op0IsKill*/,
1047 unsigned /*Op1*/, bool /*Op1IsKill*/) {
1051 unsigned FastISel::FastEmit_i(MVT, MVT, unsigned, uint64_t /*Imm*/) {
1055 unsigned FastISel::FastEmit_f(MVT, MVT,
1056 unsigned, const ConstantFP * /*FPImm*/) {
1060 unsigned FastISel::FastEmit_ri(MVT, MVT,
1062 unsigned /*Op0*/, bool /*Op0IsKill*/,
1067 unsigned FastISel::FastEmit_rf(MVT, MVT,
1069 unsigned /*Op0*/, bool /*Op0IsKill*/,
1070 const ConstantFP * /*FPImm*/) {
1074 unsigned FastISel::FastEmit_rri(MVT, MVT,
1076 unsigned /*Op0*/, bool /*Op0IsKill*/,
1077 unsigned /*Op1*/, bool /*Op1IsKill*/,
1082 /// FastEmit_ri_ - This method is a wrapper of FastEmit_ri. It first tries
1083 /// to emit an instruction with an immediate operand using FastEmit_ri.
1084 /// If that fails, it materializes the immediate into a register and try
1085 /// FastEmit_rr instead.
1086 unsigned FastISel::FastEmit_ri_(MVT VT, unsigned Opcode,
1087 unsigned Op0, bool Op0IsKill,
1088 uint64_t Imm, MVT ImmType) {
1089 // If this is a multiply by a power of two, emit this as a shift left.
1090 if (Opcode == ISD::MUL && isPowerOf2_64(Imm)) {
1093 } else if (Opcode == ISD::UDIV && isPowerOf2_64(Imm)) {
1094 // div x, 8 -> srl x, 3
1099 // Horrible hack (to be removed), check to make sure shift amounts are
1101 if ((Opcode == ISD::SHL || Opcode == ISD::SRA || Opcode == ISD::SRL) &&
1102 Imm >= VT.getSizeInBits())
1105 // First check if immediate type is legal. If not, we can't use the ri form.
1106 unsigned ResultReg = FastEmit_ri(VT, VT, Opcode, Op0, Op0IsKill, Imm);
1109 unsigned MaterialReg = FastEmit_i(ImmType, ImmType, ISD::Constant, Imm);
1110 if (MaterialReg == 0) {
1111 // This is a bit ugly/slow, but failing here means falling out of
1112 // fast-isel, which would be very slow.
1113 IntegerType *ITy = IntegerType::get(FuncInfo.Fn->getContext(),
1114 VT.getSizeInBits());
1115 MaterialReg = getRegForValue(ConstantInt::get(ITy, Imm));
1117 return FastEmit_rr(VT, VT, Opcode,
1119 MaterialReg, /*Kill=*/true);
1122 unsigned FastISel::createResultReg(const TargetRegisterClass* RC) {
1123 return MRI.createVirtualRegister(RC);
1126 unsigned FastISel::FastEmitInst_(unsigned MachineInstOpcode,
1127 const TargetRegisterClass* RC) {
1128 unsigned ResultReg = createResultReg(RC);
1129 const MCInstrDesc &II = TII.get(MachineInstOpcode);
1131 BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL, II, ResultReg);
1135 unsigned FastISel::FastEmitInst_r(unsigned MachineInstOpcode,
1136 const TargetRegisterClass *RC,
1137 unsigned Op0, bool Op0IsKill) {
1138 unsigned ResultReg = createResultReg(RC);
1139 const MCInstrDesc &II = TII.get(MachineInstOpcode);
1141 if (II.getNumDefs() >= 1)
1142 BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL, II, ResultReg)
1143 .addReg(Op0, Op0IsKill * RegState::Kill);
1145 BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL, II)
1146 .addReg(Op0, Op0IsKill * RegState::Kill);
1147 BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL, TII.get(TargetOpcode::COPY),
1148 ResultReg).addReg(II.ImplicitDefs[0]);
1154 unsigned FastISel::FastEmitInst_rr(unsigned MachineInstOpcode,
1155 const TargetRegisterClass *RC,
1156 unsigned Op0, bool Op0IsKill,
1157 unsigned Op1, bool Op1IsKill) {
1158 unsigned ResultReg = createResultReg(RC);
1159 const MCInstrDesc &II = TII.get(MachineInstOpcode);
1161 if (II.getNumDefs() >= 1)
1162 BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL, II, ResultReg)
1163 .addReg(Op0, Op0IsKill * RegState::Kill)
1164 .addReg(Op1, Op1IsKill * RegState::Kill);
1166 BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL, II)
1167 .addReg(Op0, Op0IsKill * RegState::Kill)
1168 .addReg(Op1, Op1IsKill * RegState::Kill);
1169 BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL, TII.get(TargetOpcode::COPY),
1170 ResultReg).addReg(II.ImplicitDefs[0]);
1175 unsigned FastISel::FastEmitInst_rrr(unsigned MachineInstOpcode,
1176 const TargetRegisterClass *RC,
1177 unsigned Op0, bool Op0IsKill,
1178 unsigned Op1, bool Op1IsKill,
1179 unsigned Op2, bool Op2IsKill) {
1180 unsigned ResultReg = createResultReg(RC);
1181 const MCInstrDesc &II = TII.get(MachineInstOpcode);
1183 if (II.getNumDefs() >= 1)
1184 BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL, II, ResultReg)
1185 .addReg(Op0, Op0IsKill * RegState::Kill)
1186 .addReg(Op1, Op1IsKill * RegState::Kill)
1187 .addReg(Op2, Op2IsKill * RegState::Kill);
1189 BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL, II)
1190 .addReg(Op0, Op0IsKill * RegState::Kill)
1191 .addReg(Op1, Op1IsKill * RegState::Kill)
1192 .addReg(Op2, Op2IsKill * RegState::Kill);
1193 BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL, TII.get(TargetOpcode::COPY),
1194 ResultReg).addReg(II.ImplicitDefs[0]);
1199 unsigned FastISel::FastEmitInst_ri(unsigned MachineInstOpcode,
1200 const TargetRegisterClass *RC,
1201 unsigned Op0, bool Op0IsKill,
1203 unsigned ResultReg = createResultReg(RC);
1204 const MCInstrDesc &II = TII.get(MachineInstOpcode);
1206 if (II.getNumDefs() >= 1)
1207 BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL, II, ResultReg)
1208 .addReg(Op0, Op0IsKill * RegState::Kill)
1211 BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL, II)
1212 .addReg(Op0, Op0IsKill * RegState::Kill)
1214 BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL, TII.get(TargetOpcode::COPY),
1215 ResultReg).addReg(II.ImplicitDefs[0]);
1220 unsigned FastISel::FastEmitInst_rii(unsigned MachineInstOpcode,
1221 const TargetRegisterClass *RC,
1222 unsigned Op0, bool Op0IsKill,
1223 uint64_t Imm1, uint64_t Imm2) {
1224 unsigned ResultReg = createResultReg(RC);
1225 const MCInstrDesc &II = TII.get(MachineInstOpcode);
1227 if (II.getNumDefs() >= 1)
1228 BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL, II, ResultReg)
1229 .addReg(Op0, Op0IsKill * RegState::Kill)
1233 BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL, II)
1234 .addReg(Op0, Op0IsKill * RegState::Kill)
1237 BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL, TII.get(TargetOpcode::COPY),
1238 ResultReg).addReg(II.ImplicitDefs[0]);
1243 unsigned FastISel::FastEmitInst_rf(unsigned MachineInstOpcode,
1244 const TargetRegisterClass *RC,
1245 unsigned Op0, bool Op0IsKill,
1246 const ConstantFP *FPImm) {
1247 unsigned ResultReg = createResultReg(RC);
1248 const MCInstrDesc &II = TII.get(MachineInstOpcode);
1250 if (II.getNumDefs() >= 1)
1251 BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL, II, ResultReg)
1252 .addReg(Op0, Op0IsKill * RegState::Kill)
1255 BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL, II)
1256 .addReg(Op0, Op0IsKill * RegState::Kill)
1258 BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL, TII.get(TargetOpcode::COPY),
1259 ResultReg).addReg(II.ImplicitDefs[0]);
1264 unsigned FastISel::FastEmitInst_rri(unsigned MachineInstOpcode,
1265 const TargetRegisterClass *RC,
1266 unsigned Op0, bool Op0IsKill,
1267 unsigned Op1, bool Op1IsKill,
1269 unsigned ResultReg = createResultReg(RC);
1270 const MCInstrDesc &II = TII.get(MachineInstOpcode);
1272 if (II.getNumDefs() >= 1)
1273 BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL, II, ResultReg)
1274 .addReg(Op0, Op0IsKill * RegState::Kill)
1275 .addReg(Op1, Op1IsKill * RegState::Kill)
1278 BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL, II)
1279 .addReg(Op0, Op0IsKill * RegState::Kill)
1280 .addReg(Op1, Op1IsKill * RegState::Kill)
1282 BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL, TII.get(TargetOpcode::COPY),
1283 ResultReg).addReg(II.ImplicitDefs[0]);
1288 unsigned FastISel::FastEmitInst_i(unsigned MachineInstOpcode,
1289 const TargetRegisterClass *RC,
1291 unsigned ResultReg = createResultReg(RC);
1292 const MCInstrDesc &II = TII.get(MachineInstOpcode);
1294 if (II.getNumDefs() >= 1)
1295 BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL, II, ResultReg).addImm(Imm);
1297 BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL, II).addImm(Imm);
1298 BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL, TII.get(TargetOpcode::COPY),
1299 ResultReg).addReg(II.ImplicitDefs[0]);
1304 unsigned FastISel::FastEmitInst_ii(unsigned MachineInstOpcode,
1305 const TargetRegisterClass *RC,
1306 uint64_t Imm1, uint64_t Imm2) {
1307 unsigned ResultReg = createResultReg(RC);
1308 const MCInstrDesc &II = TII.get(MachineInstOpcode);
1310 if (II.getNumDefs() >= 1)
1311 BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL, II, ResultReg)
1312 .addImm(Imm1).addImm(Imm2);
1314 BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL, II).addImm(Imm1).addImm(Imm2);
1315 BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL, TII.get(TargetOpcode::COPY),
1316 ResultReg).addReg(II.ImplicitDefs[0]);
1321 unsigned FastISel::FastEmitInst_extractsubreg(MVT RetVT,
1322 unsigned Op0, bool Op0IsKill,
1324 unsigned ResultReg = createResultReg(TLI.getRegClassFor(RetVT));
1325 assert(TargetRegisterInfo::isVirtualRegister(Op0) &&
1326 "Cannot yet extract from physregs");
1327 BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt,
1328 DL, TII.get(TargetOpcode::COPY), ResultReg)
1329 .addReg(Op0, getKillRegState(Op0IsKill), Idx);
1333 /// FastEmitZExtFromI1 - Emit MachineInstrs to compute the value of Op
1334 /// with all but the least significant bit set to zero.
1335 unsigned FastISel::FastEmitZExtFromI1(MVT VT, unsigned Op0, bool Op0IsKill) {
1336 return FastEmit_ri(VT, VT, ISD::AND, Op0, Op0IsKill, 1);
1339 /// HandlePHINodesInSuccessorBlocks - Handle PHI nodes in successor blocks.
1340 /// Emit code to ensure constants are copied into registers when needed.
1341 /// Remember the virtual registers that need to be added to the Machine PHI
1342 /// nodes as input. We cannot just directly add them, because expansion
1343 /// might result in multiple MBB's for one BB. As such, the start of the
1344 /// BB might correspond to a different MBB than the end.
1345 bool FastISel::HandlePHINodesInSuccessorBlocks(const BasicBlock *LLVMBB) {
1346 const TerminatorInst *TI = LLVMBB->getTerminator();
1348 SmallPtrSet<MachineBasicBlock *, 4> SuccsHandled;
1349 unsigned OrigNumPHINodesToUpdate = FuncInfo.PHINodesToUpdate.size();
1351 // Check successor nodes' PHI nodes that expect a constant to be available
1353 for (unsigned succ = 0, e = TI->getNumSuccessors(); succ != e; ++succ) {
1354 const BasicBlock *SuccBB = TI->getSuccessor(succ);
1355 if (!isa<PHINode>(SuccBB->begin())) continue;
1356 MachineBasicBlock *SuccMBB = FuncInfo.MBBMap[SuccBB];
1358 // If this terminator has multiple identical successors (common for
1359 // switches), only handle each succ once.
1360 if (!SuccsHandled.insert(SuccMBB)) continue;
1362 MachineBasicBlock::iterator MBBI = SuccMBB->begin();
1364 // At this point we know that there is a 1-1 correspondence between LLVM PHI
1365 // nodes and Machine PHI nodes, but the incoming operands have not been
1367 for (BasicBlock::const_iterator I = SuccBB->begin();
1368 const PHINode *PN = dyn_cast<PHINode>(I); ++I) {
1370 // Ignore dead phi's.
1371 if (PN->use_empty()) continue;
1373 // Only handle legal types. Two interesting things to note here. First,
1374 // by bailing out early, we may leave behind some dead instructions,
1375 // since SelectionDAG's HandlePHINodesInSuccessorBlocks will insert its
1376 // own moves. Second, this check is necessary because FastISel doesn't
1377 // use CreateRegs to create registers, so it always creates
1378 // exactly one register for each non-void instruction.
1379 EVT VT = TLI.getValueType(PN->getType(), /*AllowUnknown=*/true);
1380 if (VT == MVT::Other || !TLI.isTypeLegal(VT)) {
1381 // Handle integer promotions, though, because they're common and easy.
1382 if (VT == MVT::i1 || VT == MVT::i8 || VT == MVT::i16)
1383 VT = TLI.getTypeToTransformTo(LLVMBB->getContext(), VT);
1385 FuncInfo.PHINodesToUpdate.resize(OrigNumPHINodesToUpdate);
1390 const Value *PHIOp = PN->getIncomingValueForBlock(LLVMBB);
1392 // Set the DebugLoc for the copy. Prefer the location of the operand
1393 // if there is one; use the location of the PHI otherwise.
1394 DL = PN->getDebugLoc();
1395 if (const Instruction *Inst = dyn_cast<Instruction>(PHIOp))
1396 DL = Inst->getDebugLoc();
1398 unsigned Reg = getRegForValue(PHIOp);
1400 FuncInfo.PHINodesToUpdate.resize(OrigNumPHINodesToUpdate);
1403 FuncInfo.PHINodesToUpdate.push_back(std::make_pair(MBBI++, Reg));