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Refactor the bitcast code into its own function. 

llvm-svn: 55387
This commit is contained in:
Dan Gohman 2008-08-26 21:28:54 +00:00
parent 677a021665
commit 6fda9208d9
2 changed files with 72 additions and 58 deletions
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3
llvm/include/llvm/CodeGen/FastISel.h
View File

@ -167,6 +167,9 @@ private:
bool SelectGetElementPtr(Instruction *I,
DenseMap<const Value*, unsigned> &ValueMap);
bool SelectBitCast(Instruction *I,
DenseMap<const Value*, unsigned> &ValueMap);
};
}

127
llvm/lib/CodeGen/SelectionDAG/FastISel.cpp
View File

@ -149,6 +149,72 @@ bool FastISel::SelectGetElementPtr(Instruction *I,
return true;
}
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,
@ -231,64 +297,8 @@ FastISel::SelectInstructions(BasicBlock::iterator Begin,
break;
case Instruction::BitCast:
// 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 I;
ValueMap[I] = result;
break;
} else
// TODO: Support vector and fp constants.
return I;
} else 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 I;
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 I;
ValueMap[I] = ResultReg;
break;
} else
// TODO: Casting a non-integral constant?
return I;
if (!SelectBitCast(I, ValueMap)) return I;
break;
case Instruction::FPToSI:
if (!isa<ConstantFP>(I->getOperand(0))) {
@ -348,6 +358,7 @@ FastISel::SelectInstructions(BasicBlock::iterator Begin,
} else
// TODO: Materialize constant and convert to FP.
return I;
default:
// Unhandled instruction. Halt "fast" selection and bail.
return I;