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simplify some code now that types are signless

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@33232 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2007-01-15 07:02:54 +00:00
parent 836692dd8a
commit 76b7a06a75
1 changed files with 12 additions and 46 deletions
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52
lib/Transforms/Scalar/InstructionCombining.cpp
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@ -1927,21 +1927,6 @@ static bool isSignBit(ConstantInt *CI) {
return (CI->getZExtValue() & (~0ULL >> (64-NumBits))) == (1ULL << (NumBits-1));
}
/// RemoveNoopCast - Strip off nonconverting casts from the value.
///
static Value *RemoveNoopCast(Value *V) {
if (CastInst *CI = dyn_cast<CastInst>(V)) {
const Type *CTy = CI->getType();
const Type *OpTy = CI->getOperand(0)->getType();
if (CTy->isInteger() && OpTy->isInteger()) {
if (CTy->getPrimitiveSizeInBits() == OpTy->getPrimitiveSizeInBits())
return RemoveNoopCast(CI->getOperand(0));
} else if (isa<PointerType>(CTy) && isa<PointerType>(OpTy))
return RemoveNoopCast(CI->getOperand(0));
}
return V;
}
Instruction *InstCombiner::visitSub(BinaryOperator &I) {
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
@ -1967,21 +1952,17 @@ Instruction *InstCombiner::visitSub(BinaryOperator &I) {
if (match(Op1, m_Not(m_Value(X))))
return BinaryOperator::createAdd(X,
ConstantExpr::getAdd(C, ConstantInt::get(I.getType(), 1)));
// -((uint)X >> 31) -> ((int)X >> 31)
// -((int)X >> 31) -> ((uint)X >> 31)
// -(X >>u 31) -> (X >>s 31)
// -(X >>s 31) -> (X >>u 31)
if (C->isNullValue()) {
Value *NoopCastedRHS = RemoveNoopCast(Op1);
if (ShiftInst *SI = dyn_cast<ShiftInst>(NoopCastedRHS))
if (ShiftInst *SI = dyn_cast<ShiftInst>(Op1))
if (SI->getOpcode() == Instruction::LShr) {
if (ConstantInt *CU = dyn_cast<ConstantInt>(SI->getOperand(1))) {
// Check to see if we are shifting out everything but the sign bit.
if (CU->getZExtValue() ==
SI->getType()->getPrimitiveSizeInBits()-1) {
// Ok, the transformation is safe. Insert AShr.
// FIXME: Once integer types are signless, this cast should be
// removed.
Value *ShiftOp = SI->getOperand(0);
return new ShiftInst(Instruction::AShr, ShiftOp, CU,
return new ShiftInst(Instruction::AShr, SI->getOperand(0), CU,
SI->getName());
}
}
@ -1991,7 +1972,6 @@ Instruction *InstCombiner::visitSub(BinaryOperator &I) {
// Check to see if we are shifting out everything but the sign bit.
if (CU->getZExtValue() ==
SI->getType()->getPrimitiveSizeInBits()-1) {
// Ok, the transformation is safe. Insert LShr.
return new ShiftInst(Instruction::LShr, SI->getOperand(0), CU,
SI->getName());
@ -7664,28 +7644,14 @@ Instruction *InstCombiner::visitGetElementPtrInst(GetElementPtrInst &GEP) {
for (unsigned i = 1, e = GEP.getNumOperands(); i != e; ++i, ++GTI)
if (isa<SequentialType>(*GTI)) {
if (CastInst *CI = dyn_cast<CastInst>(GEP.getOperand(i))) {
Value *Src = CI->getOperand(0);
const Type *SrcTy = Src->getType();
const Type *DestTy = CI->getType();
if (Src->getType()->isInteger()) {
if (SrcTy->getPrimitiveSizeInBits() ==
DestTy->getPrimitiveSizeInBits()) {
// We can always eliminate a cast from ulong or long to the other.
// We can always eliminate a cast from uint to int or the other on
// 32-bit pointer platforms.
if (DestTy->getPrimitiveSizeInBits() >= TD->getPointerSizeInBits()){
MadeChange = true;
GEP.setOperand(i, Src);
}
} else if (SrcTy->getPrimitiveSizeInBits() <
DestTy->getPrimitiveSizeInBits() &&
SrcTy->getPrimitiveSizeInBits() == 32) {
// We can eliminate a cast from [u]int to [u]long iff the target
if (CI->getOpcode() == Instruction::ZExt ||
CI->getOpcode() == Instruction::SExt) {
const Type *SrcTy = CI->getOperand(0)->getType();
// We can eliminate a cast from i32 to i64 iff the target
// is a 32-bit pointer target.
if (SrcTy->getPrimitiveSizeInBits() >= TD->getPointerSizeInBits()) {
MadeChange = true;
GEP.setOperand(i, Src);
}
GEP.setOperand(i, CI->getOperand(0));
}
}
}