llvm-6502/lib/CodeGen/SelectionDAG/FastISel.cpp
2008-08-27 01:09:54 +00:00

622 lines
22 KiB
C++

///===-- FastISel.cpp - Implementation of the FastISel class --------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file contains the implementation of the FastISel class.
//
//===----------------------------------------------------------------------===//
#include "llvm/Instructions.h"
#include "llvm/CodeGen/FastISel.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/Target/TargetData.h"
#include "llvm/Target/TargetInstrInfo.h"
#include "llvm/Target/TargetLowering.h"
#include "llvm/Target/TargetMachine.h"
using namespace llvm;
/// SelectBinaryOp - Select and emit code for a binary operator instruction,
/// which has an opcode which directly corresponds to the given ISD opcode.
///
bool FastISel::SelectBinaryOp(Instruction *I, ISD::NodeType ISDOpcode,
DenseMap<const Value*, unsigned> &ValueMap) {
MVT VT = MVT::getMVT(I->getType(), /*HandleUnknown=*/true);
if (VT == MVT::Other || !VT.isSimple())
// Unhandled type. Halt "fast" selection and bail.
return false;
// We only handle legal types. For example, on x86-32 the instruction
// selector contains all of the 64-bit instructions from x86-64,
// under the assumption that i64 won't be used if the target doesn't
// support it.
if (!TLI.isTypeLegal(VT))
return false;
unsigned Op0 = ValueMap[I->getOperand(0)];
if (Op0 == 0)
// Unhandled operand. Halt "fast" selection and bail.
return false;
// Check if the second operand is a constant and handle it appropriately.
if (ConstantInt *CI = dyn_cast<ConstantInt>(I->getOperand(1))) {
unsigned ResultReg = FastEmit_ri_(VT.getSimpleVT(), ISDOpcode, Op0,
CI->getZExtValue(), VT.getSimpleVT());
if (ResultReg == 0)
// Target-specific code wasn't able to find a machine opcode for
// the given ISD opcode and type. Halt "fast" selection and bail.
return false;
// We successfully emitted code for the given LLVM Instruction.
ValueMap[I] = ResultReg;
return true;
}
// Check if the second operand is a constant float.
if (ConstantFP *CF = dyn_cast<ConstantFP>(I->getOperand(1))) {
unsigned ResultReg = FastEmit_rf_(VT.getSimpleVT(), ISDOpcode, Op0,
CF, VT.getSimpleVT());
if (ResultReg == 0)
// Target-specific code wasn't able to find a machine opcode for
// the given ISD opcode and type. Halt "fast" selection and bail.
return false;
// We successfully emitted code for the given LLVM Instruction.
ValueMap[I] = ResultReg;
return true;
}
unsigned Op1 = ValueMap[I->getOperand(1)];
if (Op1 == 0)
// Unhandled operand. Halt "fast" selection and bail.
return false;
unsigned ResultReg = FastEmit_rr(VT.getSimpleVT(), VT.getSimpleVT(),
ISDOpcode, Op0, Op1);
if (ResultReg == 0)
// Target-specific code wasn't able to find a machine opcode for
// the given ISD opcode and type. Halt "fast" selection and bail.
return false;
// We successfully emitted code for the given LLVM Instruction.
ValueMap[I] = ResultReg;
return true;
}
bool FastISel::SelectGetElementPtr(Instruction *I,
DenseMap<const Value*, unsigned> &ValueMap) {
unsigned N = ValueMap[I->getOperand(0)];
if (N == 0)
// Unhandled operand. Halt "fast" selection and bail.
return false;
const Type *Ty = I->getOperand(0)->getType();
MVT::SimpleValueType VT = TLI.getPointerTy().getSimpleVT();
for (GetElementPtrInst::op_iterator OI = I->op_begin()+1, E = I->op_end();
OI != E; ++OI) {
Value *Idx = *OI;
if (const StructType *StTy = dyn_cast<StructType>(Ty)) {
unsigned Field = cast<ConstantInt>(Idx)->getZExtValue();
if (Field) {
// N = N + Offset
uint64_t Offs = TD.getStructLayout(StTy)->getElementOffset(Field);
// FIXME: This can be optimized by combining the add with a
// subsequent one.
N = FastEmit_ri_(VT, ISD::ADD, N, Offs, VT);
if (N == 0)
// Unhandled operand. Halt "fast" selection and bail.
return false;
}
Ty = StTy->getElementType(Field);
} else {
Ty = cast<SequentialType>(Ty)->getElementType();
// If this is a constant subscript, handle it quickly.
if (ConstantInt *CI = dyn_cast<ConstantInt>(Idx)) {
if (CI->getZExtValue() == 0) continue;
uint64_t Offs =
TD.getABITypeSize(Ty)*cast<ConstantInt>(CI)->getSExtValue();
N = FastEmit_ri_(VT, ISD::ADD, N, Offs, VT);
if (N == 0)
// Unhandled operand. Halt "fast" selection and bail.
return false;
continue;
}
// N = N + Idx * ElementSize;
uint64_t ElementSize = TD.getABITypeSize(Ty);
unsigned IdxN = ValueMap[Idx];
if (IdxN == 0)
// Unhandled operand. Halt "fast" selection and bail.
return false;
// If the index is smaller or larger than intptr_t, truncate or extend
// it.
MVT IdxVT = MVT::getMVT(Idx->getType(), /*HandleUnknown=*/false);
if (IdxVT.bitsLT(VT))
IdxN = FastEmit_r(IdxVT.getSimpleVT(), VT, ISD::SIGN_EXTEND, IdxN);
else if (IdxVT.bitsGT(VT))
IdxN = FastEmit_r(IdxVT.getSimpleVT(), VT, ISD::TRUNCATE, IdxN);
if (IdxN == 0)
// Unhandled operand. Halt "fast" selection and bail.
return false;
if (ElementSize != 1) {
IdxN = FastEmit_ri_(VT, ISD::MUL, IdxN, ElementSize, VT);
if (IdxN == 0)
// Unhandled operand. Halt "fast" selection and bail.
return false;
}
N = FastEmit_rr(VT, VT, ISD::ADD, N, IdxN);
if (N == 0)
// Unhandled operand. Halt "fast" selection and bail.
return false;
}
}
// We successfully emitted code for the given LLVM Instruction.
ValueMap[I] = N;
return true;
}
bool FastISel::SelectCast(Instruction *I, ISD::NodeType Opcode,
DenseMap<const Value*, unsigned> &ValueMap) {
MVT SrcVT = MVT::getMVT(I->getOperand(0)->getType());
MVT DstVT = MVT::getMVT(I->getType());
if (SrcVT == MVT::Other || !SrcVT.isSimple() ||
DstVT == MVT::Other || !DstVT.isSimple() ||
!TLI.isTypeLegal(SrcVT) || !TLI.isTypeLegal(DstVT))
// Unhandled type. Halt "fast" selection and bail.
return false;
unsigned InputReg = ValueMap[I->getOperand(0)];
if (!InputReg)
// Unhandled operand. Halt "fast" selection and bail.
return false;
unsigned ResultReg = FastEmit_r(SrcVT.getSimpleVT(),
DstVT.getSimpleVT(),
Opcode,
InputReg);
if (!ResultReg)
return false;
ValueMap[I] = ResultReg;
return true;
}
bool FastISel::SelectConstantCast(Instruction* I, ISD::NodeType Opcode,
DenseMap<const Value*, unsigned> &ValueMap) {
// Materialize constant and convert.
ConstantInt* CI = cast<ConstantInt>(I->getOperand(0));
MVT SrcVT = MVT::getMVT(CI->getType());
MVT DstVT = MVT::getMVT(I->getType());
if (SrcVT == MVT::Other || !SrcVT.isSimple() ||
DstVT == MVT::Other || !DstVT.isSimple() ||
!TLI.isTypeLegal(SrcVT) || !TLI.isTypeLegal(DstVT))
// Unhandled type. Halt "fast" selection and bail.
return false;
unsigned ResultReg1 = FastEmit_i(SrcVT.getSimpleVT(),
SrcVT.getSimpleVT(),
ISD::Constant, CI->getZExtValue());
if (!ResultReg1)
return false;
unsigned ResultReg2 = FastEmit_r(SrcVT.getSimpleVT(),
DstVT.getSimpleVT(),
Opcode,
ResultReg1);
if (!ResultReg2)
return false;
ValueMap[I] = ResultReg2;
return true;
}
bool FastISel::SelectConstantFPCast(Instruction* I, ISD::NodeType Opcode,
DenseMap<const Value*, unsigned> &ValueMap) {
// TODO: Implement casting of FP constants by materialization
// followed by conversion.
return false;
}
bool FastISel::SelectBitCast(Instruction *I,
DenseMap<const Value*, unsigned> &ValueMap) {
// BitCast consists of either an immediate to register move
// or a register to register move.
if (ConstantInt* CI = dyn_cast<ConstantInt>(I->getOperand(0))) {
if (I->getType()->isInteger()) {
MVT VT = MVT::getMVT(I->getType(), /*HandleUnknown=*/false);
unsigned result = FastEmit_i(VT.getSimpleVT(), VT.getSimpleVT(),
ISD::Constant,
CI->getZExtValue());
if (!result)
return false;
ValueMap[I] = result;
return true;
}
// TODO: Support vector and fp constants.
return false;
}
if (!isa<Constant>(I->getOperand(0))) {
// Bitcasts of non-constant values become reg-reg copies.
MVT SrcVT = MVT::getMVT(I->getOperand(0)->getType());
MVT DstVT = MVT::getMVT(I->getType());
if (SrcVT == MVT::Other || !SrcVT.isSimple() ||
DstVT == MVT::Other || !DstVT.isSimple() ||
!TLI.isTypeLegal(SrcVT) || !TLI.isTypeLegal(DstVT))
// Unhandled type. Halt "fast" selection and bail.
return false;
unsigned Op0 = ValueMap[I->getOperand(0)];
if (Op0 == 0)
// Unhandled operand. Halt "fast" selection and bail.
return false;
// First, try to perform the bitcast by inserting a reg-reg copy.
unsigned ResultReg = 0;
if (SrcVT.getSimpleVT() == DstVT.getSimpleVT()) {
TargetRegisterClass* SrcClass = TLI.getRegClassFor(SrcVT);
TargetRegisterClass* DstClass = TLI.getRegClassFor(DstVT);
ResultReg = createResultReg(DstClass);
bool InsertedCopy = TII.copyRegToReg(*MBB, MBB->end(), ResultReg,
Op0, DstClass, SrcClass);
if (!InsertedCopy)
ResultReg = 0;
}
// If the reg-reg copy failed, select a BIT_CONVERT opcode.
if (!ResultReg)
ResultReg = FastEmit_r(SrcVT.getSimpleVT(), DstVT.getSimpleVT(),
ISD::BIT_CONVERT, Op0);
if (!ResultReg)
return false;
ValueMap[I] = ResultReg;
return true;
}
// TODO: Casting a non-integral constant?
return false;
}
BasicBlock::iterator
FastISel::SelectInstructions(BasicBlock::iterator Begin,
BasicBlock::iterator End,
DenseMap<const Value*, unsigned> &ValueMap,
DenseMap<const BasicBlock*,
MachineBasicBlock *> &MBBMap,
MachineBasicBlock *mbb) {
MBB = mbb;
BasicBlock::iterator I = Begin;
for (; I != End; ++I) {
switch (I->getOpcode()) {
case Instruction::Add: {
ISD::NodeType Opc = I->getType()->isFPOrFPVector() ? ISD::FADD : ISD::ADD;
if (!SelectBinaryOp(I, Opc, ValueMap)) return I; break;
}
case Instruction::Sub: {
ISD::NodeType Opc = I->getType()->isFPOrFPVector() ? ISD::FSUB : ISD::SUB;
if (!SelectBinaryOp(I, Opc, ValueMap)) return I; break;
}
case Instruction::Mul: {
ISD::NodeType Opc = I->getType()->isFPOrFPVector() ? ISD::FMUL : ISD::MUL;
if (!SelectBinaryOp(I, Opc, ValueMap)) return I; break;
}
case Instruction::SDiv:
if (!SelectBinaryOp(I, ISD::SDIV, ValueMap)) return I; break;
case Instruction::UDiv:
if (!SelectBinaryOp(I, ISD::UDIV, ValueMap)) return I; break;
case Instruction::FDiv:
if (!SelectBinaryOp(I, ISD::FDIV, ValueMap)) return I; break;
case Instruction::SRem:
if (!SelectBinaryOp(I, ISD::SREM, ValueMap)) return I; break;
case Instruction::URem:
if (!SelectBinaryOp(I, ISD::UREM, ValueMap)) return I; break;
case Instruction::FRem:
if (!SelectBinaryOp(I, ISD::FREM, ValueMap)) return I; break;
case Instruction::Shl:
if (!SelectBinaryOp(I, ISD::SHL, ValueMap)) return I; break;
case Instruction::LShr:
if (!SelectBinaryOp(I, ISD::SRL, ValueMap)) return I; break;
case Instruction::AShr:
if (!SelectBinaryOp(I, ISD::SRA, ValueMap)) return I; break;
case Instruction::And:
if (!SelectBinaryOp(I, ISD::AND, ValueMap)) return I; break;
case Instruction::Or:
if (!SelectBinaryOp(I, ISD::OR, ValueMap)) return I; break;
case Instruction::Xor:
if (!SelectBinaryOp(I, ISD::XOR, ValueMap)) return I; break;
case Instruction::GetElementPtr:
if (!SelectGetElementPtr(I, ValueMap)) return I;
break;
case Instruction::Br: {
BranchInst *BI = cast<BranchInst>(I);
if (BI->isUnconditional()) {
MachineFunction::iterator NextMBB =
next(MachineFunction::iterator(MBB));
BasicBlock *LLVMSucc = BI->getSuccessor(0);
MachineBasicBlock *MSucc = MBBMap[LLVMSucc];
if (NextMBB != MF.end() && MSucc == NextMBB) {
// The unconditional fall-through case, which needs no instructions.
} else {
// The unconditional branch case.
TII.InsertBranch(*MBB, MSucc, NULL, SmallVector<MachineOperand, 0>());
}
MBB->addSuccessor(MSucc);
break;
}
// Conditional branches are not handed yet.
// Halt "fast" selection and bail.
return I;
}
case Instruction::PHI:
// PHI nodes are already emitted.
break;
case Instruction::BitCast:
if (!SelectBitCast(I, ValueMap)) return I; break;
case Instruction::FPToSI:
if (!isa<ConstantFP>(I->getOperand(0))) {
if (!SelectCast(I, ISD::FP_TO_SINT, ValueMap)) return I;
} else
if (!SelectConstantFPCast(I, ISD::FP_TO_SINT, ValueMap)) return I;
break;
case Instruction::ZExt:
if (!isa<ConstantInt>(I->getOperand(0))) {
if (!SelectCast(I, ISD::ZERO_EXTEND, ValueMap)) return I;
} else
if (!SelectConstantCast(I, ISD::ZERO_EXTEND, ValueMap)) return I;
break;
case Instruction::SExt:
if (!isa<ConstantInt>(I->getOperand(0))) {
if (!SelectCast(I, ISD::SIGN_EXTEND, ValueMap)) return I;
} else
if (!SelectConstantCast(I, ISD::SIGN_EXTEND, ValueMap)) return I;
break;
case Instruction::SIToFP:
if (!isa<ConstantInt>(I->getOperand(0))) {
if (!SelectCast(I, ISD::SINT_TO_FP, ValueMap)) return I;
} else
if (!SelectConstantCast(I, ISD::SINT_TO_FP, ValueMap)) return I;
break;
case Instruction::IntToPtr: // Deliberate fall-through.
case Instruction::PtrToInt: {
MVT SrcVT = TLI.getValueType(I->getOperand(0)->getType());
MVT DstVT = TLI.getValueType(I->getType());
if (SrcVT.getSimpleVT() == DstVT.getSimpleVT()) {
if (ValueMap[I->getOperand(0)]) {
ValueMap[I] = ValueMap[I->getOperand(0)];
break;
} else
// Unhandled operand
return I;
} else if (DstVT.bitsGT(SrcVT)) {
if (!isa<ConstantInt>(I->getOperand(0))) {
if (!SelectCast(I, ISD::ZERO_EXTEND, ValueMap)) return I;
} else
if (!SelectConstantCast(I, ISD::ZERO_EXTEND, ValueMap)) return I;
break;
} else {
// TODO: Handle SrcVT > DstVT, where truncation is needed.
return I;
}
}
default:
// Unhandled instruction. Halt "fast" selection and bail.
return I;
}
}
return I;
}
FastISel::FastISel(MachineFunction &mf)
: MF(mf),
MRI(mf.getRegInfo()),
TM(mf.getTarget()),
TD(*TM.getTargetData()),
TII(*TM.getInstrInfo()),
TLI(*TM.getTargetLowering()) {
}
FastISel::~FastISel() {}
unsigned FastISel::FastEmit_(MVT::SimpleValueType, MVT::SimpleValueType, ISD::NodeType) {
return 0;
}
unsigned FastISel::FastEmit_r(MVT::SimpleValueType, MVT::SimpleValueType,
ISD::NodeType, unsigned /*Op0*/) {
return 0;
}
unsigned FastISel::FastEmit_rr(MVT::SimpleValueType, MVT::SimpleValueType,
ISD::NodeType, unsigned /*Op0*/,
unsigned /*Op0*/) {
return 0;
}
unsigned FastISel::FastEmit_i(MVT::SimpleValueType, MVT::SimpleValueType,
ISD::NodeType, uint64_t /*Imm*/) {
return 0;
}
unsigned FastISel::FastEmit_f(MVT::SimpleValueType, MVT::SimpleValueType,
ISD::NodeType, ConstantFP * /*FPImm*/) {
return 0;
}
unsigned FastISel::FastEmit_ri(MVT::SimpleValueType, MVT::SimpleValueType,
ISD::NodeType, unsigned /*Op0*/,
uint64_t /*Imm*/) {
return 0;
}
unsigned FastISel::FastEmit_rf(MVT::SimpleValueType, MVT::SimpleValueType,
ISD::NodeType, unsigned /*Op0*/,
ConstantFP * /*FPImm*/) {
return 0;
}
unsigned FastISel::FastEmit_rri(MVT::SimpleValueType, MVT::SimpleValueType,
ISD::NodeType,
unsigned /*Op0*/, unsigned /*Op1*/,
uint64_t /*Imm*/) {
return 0;
}
/// FastEmit_ri_ - This method is a wrapper of FastEmit_ri. It first tries
/// to emit an instruction with an immediate operand using FastEmit_ri.
/// If that fails, it materializes the immediate into a register and try
/// FastEmit_rr instead.
unsigned FastISel::FastEmit_ri_(MVT::SimpleValueType VT, ISD::NodeType Opcode,
unsigned Op0, uint64_t Imm,
MVT::SimpleValueType ImmType) {
unsigned ResultReg = 0;
// First check if immediate type is legal. If not, we can't use the ri form.
if (TLI.getOperationAction(ISD::Constant, ImmType) == TargetLowering::Legal)
ResultReg = FastEmit_ri(VT, VT, Opcode, Op0, Imm);
if (ResultReg != 0)
return ResultReg;
unsigned MaterialReg = FastEmit_i(ImmType, ImmType, ISD::Constant, Imm);
if (MaterialReg == 0)
return 0;
return FastEmit_rr(VT, VT, Opcode, Op0, MaterialReg);
}
/// FastEmit_rf_ - This method is a wrapper of FastEmit_ri. It first tries
/// to emit an instruction with a floating-point immediate operand using
/// FastEmit_rf. If that fails, it materializes the immediate into a register
/// and try FastEmit_rr instead.
unsigned FastISel::FastEmit_rf_(MVT::SimpleValueType VT, ISD::NodeType Opcode,
unsigned Op0, ConstantFP *FPImm,
MVT::SimpleValueType ImmType) {
unsigned ResultReg = 0;
// First check if immediate type is legal. If not, we can't use the rf form.
if (TLI.getOperationAction(ISD::Constant, ImmType) == TargetLowering::Legal)
ResultReg = FastEmit_rf(VT, VT, Opcode, Op0, FPImm);
if (ResultReg != 0)
return ResultReg;
// Materialize the constant in a register.
unsigned MaterialReg = FastEmit_f(ImmType, ImmType, ISD::ConstantFP, FPImm);
if (MaterialReg == 0) {
const APFloat &Flt = FPImm->getValueAPF();
MVT IntVT = TLI.getPointerTy();
uint64_t x[2];
uint32_t IntBitWidth = IntVT.getSizeInBits();
if (Flt.convertToInteger(x, IntBitWidth, /*isSigned=*/true,
APFloat::rmTowardZero) != APFloat::opOK)
return 0;
APInt IntVal(IntBitWidth, 2, x);
unsigned IntegerReg = FastEmit_i(IntVT.getSimpleVT(), IntVT.getSimpleVT(),
ISD::Constant, IntVal.getZExtValue());
if (IntegerReg == 0)
return 0;
MaterialReg = FastEmit_r(IntVT.getSimpleVT(), VT,
ISD::SINT_TO_FP, IntegerReg);
if (MaterialReg == 0)
return 0;
}
return FastEmit_rr(VT, VT, Opcode, Op0, MaterialReg);
}
unsigned FastISel::createResultReg(const TargetRegisterClass* RC) {
return MRI.createVirtualRegister(RC);
}
unsigned FastISel::FastEmitInst_(unsigned MachineInstOpcode,
const TargetRegisterClass* RC) {
unsigned ResultReg = createResultReg(RC);
const TargetInstrDesc &II = TII.get(MachineInstOpcode);
BuildMI(MBB, II, ResultReg);
return ResultReg;
}
unsigned FastISel::FastEmitInst_r(unsigned MachineInstOpcode,
const TargetRegisterClass *RC,
unsigned Op0) {
unsigned ResultReg = createResultReg(RC);
const TargetInstrDesc &II = TII.get(MachineInstOpcode);
BuildMI(MBB, II, ResultReg).addReg(Op0);
return ResultReg;
}
unsigned FastISel::FastEmitInst_rr(unsigned MachineInstOpcode,
const TargetRegisterClass *RC,
unsigned Op0, unsigned Op1) {
unsigned ResultReg = createResultReg(RC);
const TargetInstrDesc &II = TII.get(MachineInstOpcode);
BuildMI(MBB, II, ResultReg).addReg(Op0).addReg(Op1);
return ResultReg;
}
unsigned FastISel::FastEmitInst_ri(unsigned MachineInstOpcode,
const TargetRegisterClass *RC,
unsigned Op0, uint64_t Imm) {
unsigned ResultReg = createResultReg(RC);
const TargetInstrDesc &II = TII.get(MachineInstOpcode);
BuildMI(MBB, II, ResultReg).addReg(Op0).addImm(Imm);
return ResultReg;
}
unsigned FastISel::FastEmitInst_rf(unsigned MachineInstOpcode,
const TargetRegisterClass *RC,
unsigned Op0, ConstantFP *FPImm) {
unsigned ResultReg = createResultReg(RC);
const TargetInstrDesc &II = TII.get(MachineInstOpcode);
BuildMI(MBB, II, ResultReg).addReg(Op0).addFPImm(FPImm);
return ResultReg;
}
unsigned FastISel::FastEmitInst_rri(unsigned MachineInstOpcode,
const TargetRegisterClass *RC,
unsigned Op0, unsigned Op1, uint64_t Imm) {
unsigned ResultReg = createResultReg(RC);
const TargetInstrDesc &II = TII.get(MachineInstOpcode);
BuildMI(MBB, II, ResultReg).addReg(Op0).addReg(Op1).addImm(Imm);
return ResultReg;
}
unsigned FastISel::FastEmitInst_i(unsigned MachineInstOpcode,
const TargetRegisterClass *RC,
uint64_t Imm) {
unsigned ResultReg = createResultReg(RC);
const TargetInstrDesc &II = TII.get(MachineInstOpcode);
BuildMI(MBB, II, ResultReg).addImm(Imm);
return ResultReg;
}