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[InstCombine] Extract code for or of icmp eq zero and icmp fold (NFC) 

To make it easier to extend this to the congruent and case.
This commit is contained in:
Nikita Popov 2022-04-22 15:07:10 +02:00
parent 7ba702644b
commit 369ef9bf60
1 changed files with 32 additions and 25 deletions
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57
llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
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@ -2381,6 +2381,34 @@ Value *InstCombinerImpl::matchSelectFromAndOr(Value *A, Value *C, Value *B,
return nullptr;
}
// (icmp eq X, 0) | (icmp ult Other, X) -> (icmp ule Other, X-1)
Value *foldAndOrOfICmpEqZeroAndICmp(ICmpInst *LHS, ICmpInst *RHS, bool IsAnd,
IRBuilderBase &Builder) {
if (IsAnd)
return nullptr;
ICmpInst::Predicate LPred = LHS->getPredicate();
ICmpInst::Predicate RPred = RHS->getPredicate();
Value *LHS0 = LHS->getOperand(0);
if (LPred != ICmpInst::ICMP_EQ || !match(LHS->getOperand(1), m_Zero()) ||
!LHS0->getType()->isIntOrIntVectorTy() ||
!(LHS->hasOneUse() || RHS->hasOneUse()))
return nullptr;
Value *Other;
if (RPred == ICmpInst::ICMP_ULT && RHS->getOperand(1) == LHS0)
Other = RHS->getOperand(0);
else if (RPred == ICmpInst::ICMP_UGT && RHS->getOperand(0) == LHS0)
Other = RHS->getOperand(1);
else
return nullptr;
return Builder.CreateICmp(
ICmpInst::ICMP_UGE,
Builder.CreateAdd(LHS0, Constant::getAllOnesValue(LHS0->getType())),
Other);
}
/// Fold (icmp)&(icmp) or (icmp)|(icmp) if possible.
Value *InstCombinerImpl::foldAndOrOfICmps(ICmpInst *LHS, ICmpInst *RHS,
BinaryOperator &BO, bool IsAnd) {
@ -2472,31 +2500,10 @@ Value *InstCombinerImpl::foldAndOrOfICmps(ICmpInst *LHS, ICmpInst *RHS,
if (Value *V = foldLogOpOfMaskedICmps(LHS, RHS, IsAnd, Builder))
return V;
if (!IsAnd && (LHS->hasOneUse() || RHS->hasOneUse())) {
// (icmp eq B, 0) | (icmp ult A, B) -> (icmp ule A, B-1)
// (icmp eq B, 0) | (icmp ugt B, A) -> (icmp ule A, B-1)
Value *A = nullptr, *B = nullptr;
if (PredL == ICmpInst::ICMP_EQ && match(LHS1, m_Zero())) {
B = LHS0;
if (PredR == ICmpInst::ICMP_ULT && LHS0 == RHS1)
A = RHS0;
else if (PredR == ICmpInst::ICMP_UGT && LHS0 == RHS0)
A = RHS1;
}
// (icmp ult A, B) | (icmp eq B, 0) -> (icmp ule A, B-1)
// (icmp ugt B, A) | (icmp eq B, 0) -> (icmp ule A, B-1)
else if (PredR == ICmpInst::ICMP_EQ && match(RHS1, m_Zero())) {
B = RHS0;
if (PredL == ICmpInst::ICMP_ULT && RHS0 == LHS1)
A = LHS0;
else if (PredL == ICmpInst::ICMP_UGT && RHS0 == LHS0)
A = LHS1;
}
if (A && B && B->getType()->isIntOrIntVectorTy())
return Builder.CreateICmp(
ICmpInst::ICMP_UGE,
Builder.CreateAdd(B, Constant::getAllOnesValue(B->getType())), A);
}
if (Value *V = foldAndOrOfICmpEqZeroAndICmp(LHS, RHS, IsAnd, Builder))
return V;
if (Value *V = foldAndOrOfICmpEqZeroAndICmp(RHS, LHS, IsAnd, Builder))
return V;
if (Value *V = foldAndOrOfICmpsWithConstEq(LHS, RHS, BO, Builder, Q))
return V;