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Some minor cleanups to instcombine; no functionality change. 

Note that the FoldOpIntoPhi call is dead because it's impossible for the 
first operand of a subtraction to be both a ConstantInt and a PHINode.

llvm-svn: 60306
This commit is contained in:
Eli Friedman 2008-11-30 21:09:11 +00:00
parent e54e8a1182
commit 55e4becba9
1 changed files with 17 additions and 56 deletions
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71
llvm/lib/Transforms/Scalar/InstructionCombining.cpp
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@ -344,13 +344,6 @@ namespace {
} }
private: private:
/// InsertOperandCastBefore - This inserts a cast of V to DestTy before the
/// InsertBefore instruction. This is specialized a bit to avoid inserting
/// casts that are known to not do anything...
///
Value *InsertOperandCastBefore(Instruction::CastOps opcode,
Value *V, const Type *DestTy,
Instruction *InsertBefore);
/// SimplifyCommutative - This performs a few simplifications for /// SimplifyCommutative - This performs a few simplifications for
/// commutative operators. /// commutative operators.
@ -505,20 +498,6 @@ static bool ValueRequiresCast(Instruction::CastOps opcode, const Value *V,
return true; return true;
} }
/// InsertOperandCastBefore - This inserts a cast of V to DestTy before the
/// InsertBefore instruction. This is specialized a bit to avoid inserting
/// casts that are known to not do anything...
///
Value *InstCombiner::InsertOperandCastBefore(Instruction::CastOps opcode,
Value *V, const Type *DestTy,
Instruction *InsertBefore) {
if (V->getType() == DestTy) return V;
if (Constant *C = dyn_cast<Constant>(V))
return ConstantExpr::getCast(opcode, C, DestTy);
return InsertCastBefore(opcode, V, DestTy, *InsertBefore);
}
// SimplifyCommutative - This performs a few simplifications for commutative // SimplifyCommutative - This performs a few simplifications for commutative
// operators: // operators:
// //
@ -1815,11 +1794,7 @@ struct AddMaskingAnd {
static Value *FoldOperationIntoSelectOperand(Instruction &I, Value *SO, static Value *FoldOperationIntoSelectOperand(Instruction &I, Value *SO,
InstCombiner *IC) { InstCombiner *IC) {
if (CastInst *CI = dyn_cast<CastInst>(&I)) { if (CastInst *CI = dyn_cast<CastInst>(&I)) {
if (Constant *SOC = dyn_cast<Constant>(SO)) return IC->InsertCastBefore(CI->getOpcode(), SO, I.getType(), I);
return ConstantExpr::getCast(CI->getOpcode(), SOC, I.getType());
return IC->InsertNewInstBefore(CastInst::Create(
CI->getOpcode(), SO, I.getType(), SO->getName() + ".cast"), I);
} }
// Figure out if the constant is the left or the right argument. // Figure out if the constant is the left or the right argument.
@ -2413,10 +2388,6 @@ Instruction *InstCombiner::visitSub(BinaryOperator &I) {
if (SelectInst *SI = dyn_cast<SelectInst>(Op1)) if (SelectInst *SI = dyn_cast<SelectInst>(Op1))
if (Instruction *R = FoldOpIntoSelect(I, SI, this)) if (Instruction *R = FoldOpIntoSelect(I, SI, this))
return R; return R;
if (isa<PHINode>(Op0))
if (Instruction *NV = FoldOpIntoPhi(I))
return NV;
} }
if (I.getType() == Type::Int1Ty) if (I.getType() == Type::Int1Ty)
@ -7893,8 +7864,8 @@ Instruction *InstCombiner::commonIntCastTransforms(CastInst &CI) {
!ValueRequiresCast(CI.getOpcode(), Op1, DestTy,TD) || !ValueRequiresCast(CI.getOpcode(), Op1, DestTy,TD) ||
!ValueRequiresCast(CI.getOpcode(), Op0, DestTy, TD)) { !ValueRequiresCast(CI.getOpcode(), Op0, DestTy, TD)) {
Instruction::CastOps opcode = CI.getOpcode(); Instruction::CastOps opcode = CI.getOpcode();
Value *Op0c = InsertOperandCastBefore(opcode, Op0, DestTy, SrcI); Value *Op0c = InsertCastBefore(opcode, Op0, DestTy, *SrcI);
Value *Op1c = InsertOperandCastBefore(opcode, Op1, DestTy, SrcI); Value *Op1c = InsertCastBefore(opcode, Op1, DestTy, *SrcI);
return BinaryOperator::Create( return BinaryOperator::Create(
cast<BinaryOperator>(SrcI)->getOpcode(), Op0c, Op1c); cast<BinaryOperator>(SrcI)->getOpcode(), Op0c, Op1c);
} }
@ -7905,7 +7876,7 @@ Instruction *InstCombiner::commonIntCastTransforms(CastInst &CI) {
SrcI->getOpcode() == Instruction::Xor && SrcI->getOpcode() == Instruction::Xor &&
Op1 == ConstantInt::getTrue() && Op1 == ConstantInt::getTrue() &&
(!Op0->hasOneUse() || !isa<CmpInst>(Op0))) { (!Op0->hasOneUse() || !isa<CmpInst>(Op0))) {
Value *New = InsertOperandCastBefore(Instruction::ZExt, Op0, DestTy, &CI); Value *New = InsertCastBefore(Instruction::ZExt, Op0, DestTy, CI);
return BinaryOperator::CreateXor(New, ConstantInt::get(CI.getType(), 1)); return BinaryOperator::CreateXor(New, ConstantInt::get(CI.getType(), 1));
} }
break; break;
@ -7920,10 +7891,10 @@ Instruction *InstCombiner::commonIntCastTransforms(CastInst &CI) {
// only be converting signedness, which is a noop. // only be converting signedness, which is a noop.
if (!ValueRequiresCast(CI.getOpcode(), Op1, DestTy, TD) || if (!ValueRequiresCast(CI.getOpcode(), Op1, DestTy, TD) ||
!ValueRequiresCast(CI.getOpcode(), Op0, DestTy, TD)) { !ValueRequiresCast(CI.getOpcode(), Op0, DestTy, TD)) {
Value *Op0c = InsertOperandCastBefore(Instruction::BitCast, Value *Op0c = InsertCastBefore(Instruction::BitCast,
Op0, DestTy, SrcI); Op0, DestTy, *SrcI);
Value *Op1c = InsertOperandCastBefore(Instruction::BitCast, Value *Op1c = InsertCastBefore(Instruction::BitCast,
Op1, DestTy, SrcI); Op1, DestTy, *SrcI);
return BinaryOperator::Create( return BinaryOperator::Create(
cast<BinaryOperator>(SrcI)->getOpcode(), Op0c, Op1c); cast<BinaryOperator>(SrcI)->getOpcode(), Op0c, Op1c);
} }
@ -7940,8 +7911,8 @@ Instruction *InstCombiner::commonIntCastTransforms(CastInst &CI) {
(DestBitSize < SrcBitSize && isa<Constant>(Op1))) { (DestBitSize < SrcBitSize && isa<Constant>(Op1))) {
Instruction::CastOps opcode = (DestBitSize == SrcBitSize ? Instruction::CastOps opcode = (DestBitSize == SrcBitSize ?
Instruction::BitCast : Instruction::Trunc); Instruction::BitCast : Instruction::Trunc);
Value *Op0c = InsertOperandCastBefore(opcode, Op0, DestTy, SrcI); Value *Op0c = InsertCastBefore(opcode, Op0, DestTy, *SrcI);
Value *Op1c = InsertOperandCastBefore(opcode, Op1, DestTy, SrcI); Value *Op1c = InsertCastBefore(opcode, Op1, DestTy, *SrcI);
return BinaryOperator::CreateShl(Op0c, Op1c); return BinaryOperator::CreateShl(Op0c, Op1c);
} }
break; break;
@ -8507,10 +8478,10 @@ Instruction *InstCombiner::visitBitCast(BitCastInst &CI) {
Tmp->getOperand(0)->getType() == DestTy) || Tmp->getOperand(0)->getType() == DestTy) ||
((Tmp = dyn_cast<CastInst>(SVI->getOperand(1))) && ((Tmp = dyn_cast<CastInst>(SVI->getOperand(1))) &&
Tmp->getOperand(0)->getType() == DestTy)) { Tmp->getOperand(0)->getType() == DestTy)) {
Value *LHS = InsertOperandCastBefore(Instruction::BitCast, Value *LHS = InsertCastBefore(Instruction::BitCast,
SVI->getOperand(0), DestTy, &CI); SVI->getOperand(0), DestTy, CI);
Value *RHS = InsertOperandCastBefore(Instruction::BitCast, Value *RHS = InsertCastBefore(Instruction::BitCast,
SVI->getOperand(1), DestTy, &CI); SVI->getOperand(1), DestTy, CI);
// Return a new shuffle vector. Use the same element ID's, as we // Return a new shuffle vector. Use the same element ID's, as we
// know the vector types match #elts. // know the vector types match #elts.
return new ShuffleVectorInst(LHS, RHS, SVI->getOperand(2)); return new ShuffleVectorInst(LHS, RHS, SVI->getOperand(2));
@ -8836,8 +8807,6 @@ Instruction *InstCombiner::visitSelectInst(SelectInst &SI) {
return CastInst::Create(Instruction::ZExt, NotCond, SI.getType()); return CastInst::Create(Instruction::ZExt, NotCond, SI.getType());
} }
// FIXME: Turn select 0/-1 and -1/0 into sext from condition!
if (ICmpInst *IC = dyn_cast<ICmpInst>(SI.getCondition())) { if (ICmpInst *IC = dyn_cast<ICmpInst>(SI.getCondition())) {
// (x <s 0) ? -1 : 0 -> ashr x, 31 // (x <s 0) ? -1 : 0 -> ashr x, 31
@ -8853,16 +8822,8 @@ Instruction *InstCombiner::visitSelectInst(SelectInst &SI) {
ShAmt, "ones"); ShAmt, "ones");
InsertNewInstBefore(SRA, SI); InsertNewInstBefore(SRA, SI);
// Finally, convert to the type of the select RHS. We figure out // Then cast to the appropriate width.
// if this requires a SExt, Trunc or BitCast based on the sizes. return CastInst::CreateIntegerCast(SRA, SI.getType(), true);
Instruction::CastOps opc = Instruction::BitCast;
uint32_t SRASize = SRA->getType()->getPrimitiveSizeInBits();
uint32_t SISize = SI.getType()->getPrimitiveSizeInBits();
if (SRASize < SISize)
opc = Instruction::SExt;
else if (SRASize > SISize)
opc = Instruction::Trunc;
return CastInst::Create(opc, SRA, SI.getType());
} }
} }