mirror of
https://github.com/RPCS3/llvm-mirror.git
synced 2024-11-24 11:42:57 +01:00
[InstCombine] add helper function for icmp+zext/sext; NFC
llvm-svn: 369421
This commit is contained in:
Sanjay Patel
parent
5d5f9fbb0b
commit
f7eabb0a58
@ -4026,6 +4026,87 @@ Instruction *InstCombiner::foldICmpEquality(ICmpInst &I) {
|
||||
return nullptr;
|
||||
}
|
||||
|
||||
static Instruction *foldICmpWithZextOrSext(ICmpInst &ICmp) {
|
||||
assert(isa<CastInst>(ICmp.getOperand(0)) && "Expected cast for operand 0");
|
||||
auto *CastOp0 = cast<CastInst>(ICmp.getOperand(0));
|
||||
Value *X;
|
||||
if (!match(CastOp0, m_ZExtOrSExt(m_Value(X))))
|
||||
return nullptr;
|
||||
|
||||
bool IsSignedExt = CastOp0->getOpcode() == Instruction::SExt;
|
||||
bool IsSignedCmp = ICmp.isSigned();
|
||||
if (auto *CastOp1 = dyn_cast<CastInst>(ICmp.getOperand(1))) {
|
||||
// If the signedness of the two casts doesn't agree (i.e. one is a sext
|
||||
// and the other is a zext), then we can't handle this.
|
||||
if (CastOp0->getOpcode() != CastOp1->getOpcode())
|
||||
return nullptr;
|
||||
|
||||
// Not an extension from the same type?
|
||||
// TODO: Handle this by extending the narrower operand to the type of
|
||||
// the wider operand.
|
||||
Value *Y = CastOp1->getOperand(0);
|
||||
if (X->getType() != Y->getType())
|
||||
return nullptr;
|
||||
|
||||
// (zext X) == (zext Y) --> X == Y
|
||||
// (sext X) == (sext Y) --> X == Y
|
||||
if (ICmp.isEquality())
|
||||
return new ICmpInst(ICmp.getPredicate(), X, Y);
|
||||
|
||||
// A signed comparison of sign extended values simplifies into a
|
||||
// signed comparison.
|
||||
if (IsSignedCmp && IsSignedExt)
|
||||
return new ICmpInst(ICmp.getPredicate(), X, Y);
|
||||
|
||||
// The other three cases all fold into an unsigned comparison.
|
||||
return new ICmpInst(ICmp.getUnsignedPredicate(), X, Y);
|
||||
}
|
||||
|
||||
// Below here, we are only folding a compare with constant.
|
||||
auto *C = dyn_cast<Constant>(ICmp.getOperand(1));
|
||||
if (!C)
|
||||
return nullptr;
|
||||
|
||||
// Compute the constant that would happen if we truncated to SrcTy then
|
||||
// re-extended to DestTy.
|
||||
Type *SrcTy = CastOp0->getSrcTy();
|
||||
Type *DestTy = CastOp0->getDestTy();
|
||||
Constant *Res1 = ConstantExpr::getTrunc(C, SrcTy);
|
||||
Constant *Res2 = ConstantExpr::getCast(CastOp0->getOpcode(), Res1, DestTy);
|
||||
|
||||
// If the re-extended constant didn't change...
|
||||
if (Res2 == C) {
|
||||
if (ICmp.isEquality())
|
||||
return new ICmpInst(ICmp.getPredicate(), X, Res1);
|
||||
|
||||
// A signed comparison of sign extended values simplifies into a
|
||||
// signed comparison.
|
||||
if (IsSignedExt && IsSignedCmp)
|
||||
return new ICmpInst(ICmp.getPredicate(), X, Res1);
|
||||
|
||||
// The other three cases all fold into an unsigned comparison.
|
||||
return new ICmpInst(ICmp.getUnsignedPredicate(), X, Res1);
|
||||
}
|
||||
|
||||
// The re-extended constant changed, partly changed (in the case of a vector),
|
||||
// or could not be determined to be equal (in the case of a constant
|
||||
// expression), so the constant cannot be represented in the shorter type.
|
||||
// All the cases that fold to true or false will have already been handled
|
||||
// by SimplifyICmpInst, so only deal with the tricky case.
|
||||
if (IsSignedCmp || !IsSignedExt || !isa<ConstantInt>(C))
|
||||
return nullptr;
|
||||
|
||||
// Is source op positive?
|
||||
// icmp ult (sext X), C --> icmp sgt X, -1
|
||||
if (ICmp.getPredicate() == ICmpInst::ICMP_ULT)
|
||||
return new ICmpInst(CmpInst::ICMP_SGT, X, Constant::getAllOnesValue(SrcTy));
|
||||
|
||||
// Is source op negative?
|
||||
// icmp ugt (sext X), C --> icmp slt X, 0
|
||||
assert(ICmp.getPredicate() == ICmpInst::ICMP_UGT && "ICmp should be folded!");
|
||||
return new ICmpInst(CmpInst::ICMP_SLT, X, Constant::getNullValue(SrcTy));
|
||||
}
|
||||
|
||||
/// Handle icmp (cast x), (cast or constant).
|
||||
Instruction *InstCombiner::foldICmpWithCastOp(ICmpInst &ICmp) {
|
||||
auto *CastOp0 = dyn_cast<CastInst>(ICmp.getOperand(0));
|
||||
@ -4067,82 +4148,7 @@ Instruction *InstCombiner::foldICmpWithCastOp(ICmpInst &ICmp) {
|
||||
return new ICmpInst(ICmp.getPredicate(), Op0Src, NewOp1);
|
||||
}
|
||||
|
||||
// The code below only handles extension cast instructions, so far.
|
||||
// Enforce this.
|
||||
if (CastOp0->getOpcode() != Instruction::ZExt &&
|
||||
CastOp0->getOpcode() != Instruction::SExt)
|
||||
return nullptr;
|
||||
|
||||
bool isSignedExt = CastOp0->getOpcode() == Instruction::SExt;
|
||||
bool isSignedCmp = ICmp.isSigned();
|
||||
|
||||
if (auto *CastOp1 = dyn_cast<CastInst>(ICmp.getOperand(1))) {
|
||||
// Not an extension from the same type?
|
||||
Value *Op1Src = CastOp1->getOperand(0);
|
||||
if (Op1Src->getType() != Op0Src->getType())
|
||||
return nullptr;
|
||||
|
||||
// If the signedness of the two casts doesn't agree (i.e. one is a sext
|
||||
// and the other is a zext), then we can't handle this.
|
||||
if (CastOp1->getOpcode() != CastOp0->getOpcode())
|
||||
return nullptr;
|
||||
|
||||
// Deal with equality cases early.
|
||||
if (ICmp.isEquality())
|
||||
return new ICmpInst(ICmp.getPredicate(), Op0Src, Op1Src);
|
||||
|
||||
// A signed comparison of sign extended values simplifies into a
|
||||
// signed comparison.
|
||||
if (isSignedCmp && isSignedExt)
|
||||
return new ICmpInst(ICmp.getPredicate(), Op0Src, Op1Src);
|
||||
|
||||
// The other three cases all fold into an unsigned comparison.
|
||||
return new ICmpInst(ICmp.getUnsignedPredicate(), Op0Src, Op1Src);
|
||||
}
|
||||
|
||||
// If we aren't dealing with a constant on the RHS, exit early.
|
||||
auto *C = dyn_cast<Constant>(ICmp.getOperand(1));
|
||||
if (!C)
|
||||
return nullptr;
|
||||
|
||||
// Compute the constant that would happen if we truncated to SrcTy then
|
||||
// re-extended to DestTy.
|
||||
Constant *Res1 = ConstantExpr::getTrunc(C, SrcTy);
|
||||
Constant *Res2 = ConstantExpr::getCast(CastOp0->getOpcode(), Res1, DestTy);
|
||||
|
||||
// If the re-extended constant didn't change...
|
||||
if (Res2 == C) {
|
||||
// Deal with equality cases early.
|
||||
if (ICmp.isEquality())
|
||||
return new ICmpInst(ICmp.getPredicate(), Op0Src, Res1);
|
||||
|
||||
// A signed comparison of sign extended values simplifies into a
|
||||
// signed comparison.
|
||||
if (isSignedExt && isSignedCmp)
|
||||
return new ICmpInst(ICmp.getPredicate(), Op0Src, Res1);
|
||||
|
||||
// The other three cases all fold into an unsigned comparison.
|
||||
return new ICmpInst(ICmp.getUnsignedPredicate(), Op0Src, Res1);
|
||||
}
|
||||
|
||||
// The re-extended constant changed, partly changed (in the case of a vector),
|
||||
// or could not be determined to be equal (in the case of a constant
|
||||
// expression), so the constant cannot be represented in the shorter type.
|
||||
// All the cases that fold to true or false will have already been handled
|
||||
// by SimplifyICmpInst, so only deal with the tricky case.
|
||||
if (isSignedCmp || !isSignedExt || !isa<ConstantInt>(C))
|
||||
return nullptr;
|
||||
|
||||
// Is source op positive?
|
||||
// icmp ult (sext X), C --> icmp sgt X, -1
|
||||
if (ICmp.getPredicate() == ICmpInst::ICMP_ULT)
|
||||
return new ICmpInst(CmpInst::ICMP_SGT, Op0Src,
|
||||
Constant::getAllOnesValue(SrcTy));
|
||||
|
||||
// Is source op negative?
|
||||
// icmp ugt (sext X), C --> icmp slt X, 0
|
||||
assert(ICmp.getPredicate() == ICmpInst::ICMP_UGT && "ICmp should be folded!");
|
||||
return new ICmpInst(CmpInst::ICMP_SLT, Op0Src, Constant::getNullValue(SrcTy));
|
||||
return foldICmpWithZextOrSext(ICmp);
|
||||
}
|
||||
|
||||
static bool isNeutralValue(Instruction::BinaryOps BinaryOp, Value *RHS) {
|
||||
|
||||
Loading…
Reference in New Issue
Block a user