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Per Chris' suggestion, get rid of the select canonicalization and just add

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the corresponding or-icmp-and pattern.  This has the added benefit of doing
the matching earlier, and thus being less susceptible to being confused by
earlier transforms.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@108429 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Owen Anderson 2010-07-15 17:24:23 +00:00
parent 2722dfa75d
commit 40bf5e7a68
2 changed files with 19 additions and 28 deletions
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19
lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
View File

@ -1177,6 +1177,25 @@ Value *InstCombiner::FoldOrOfICmps(ICmpInst *LHS, ICmpInst *RHS) {
return Builder->CreateICmp(LHSCC, NewOr, LHSCst);
}
// (icmp eq (A & C1), 0) | (icmp eq (A & C2), 0) -->
// (icmp ne (A & (C1|C2)), (C1|C2))
if (LHSCC == ICmpInst::ICMP_EQ && LHSCst->isZero()) {
Instruction *I1 = dyn_cast<Instruction>(Val);
Instruction *I2 = dyn_cast<Instruction>(Val2);
if (I1 && I1->getOpcode() == Instruction::And &&
I2 && I2->getOpcode() == Instruction::And &&
I1->getOperand(0) == I1->getOperand(0)) {
ConstantInt *CI1 = dyn_cast<ConstantInt>(I1->getOperand(1));
ConstantInt *CI2 = dyn_cast<ConstantInt>(I2->getOperand(1));
if (CI1 && !CI1->isZero() && CI2 && !CI2->isZero() &&
CI1->getValue().operator&(CI2->getValue()) == 0) {
Constant *ConstOr = ConstantExpr::getOr(CI1, CI2);
Value *NewAnd = Builder->CreateAnd(I1->getOperand(0), ConstOr);
return Builder->CreateICmp(ICmpInst::ICMP_NE, NewAnd, ConstOr);
}
}
}
// From here on, we only handle:
// (icmp1 A, C1) | (icmp2 A, C2) --> something simpler.
if (Val != Val2) return 0;

28
lib/Transforms/InstCombine/InstCombineSelect.cpp
View File

@ -699,34 +699,6 @@ Instruction *InstCombiner::visitSelectInst(SelectInst &SI) {
SI.setOperand(2, TrueVal);
return &SI;
}
// select (A == 0 | B == 0), T, F--> select (A != 0 & B != 0), F, T
// Note: This is a canonicalization rather than an optimization, and is used
// to expose opportunities to other instcombine transforms.
Instruction* CondInst = dyn_cast<Instruction>(CondVal);
if (CondInst && CondInst->hasOneUse() &&
CondInst->getOpcode() == Instruction::Or) {
ICmpInst *LHSCmp = dyn_cast<ICmpInst>(CondInst->getOperand(0));
ICmpInst *RHSCmp = dyn_cast<ICmpInst>(CondInst->getOperand(1));
if (LHSCmp && LHSCmp->hasOneUse() &&
LHSCmp->getPredicate() == ICmpInst::ICMP_EQ &&
RHSCmp && RHSCmp->hasOneUse() &&
RHSCmp->getPredicate() == ICmpInst::ICMP_EQ) {
ConstantInt* C1 = dyn_cast<ConstantInt>(LHSCmp->getOperand(1));
ConstantInt* C2 = dyn_cast<ConstantInt>(RHSCmp->getOperand(1));
if (C1 && C1->isZero() && C2 && C2->isZero()) {
LHSCmp->setPredicate(ICmpInst::ICMP_NE);
RHSCmp->setPredicate(ICmpInst::ICMP_NE);
Value *And =
InsertNewInstBefore(BinaryOperator::CreateAnd(LHSCmp, RHSCmp,
"and."+CondVal->getName()), SI);
SI.setOperand(0, And);
SI.setOperand(1, FalseVal);
SI.setOperand(2, TrueVal);
return &SI;
}
}
}
return 0;
}