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Revert r314017 '[InstCombine] Simplify check for RHS being a splat constant in foldICmpUsingKnownBits by just checking Op1Min==Op1Max rather than going through m_APInt.'

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This reverts r314017 and similar code added in later commits. It seems to not work for pointer compares and is causing a bot failure for the last several days.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@314360 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Craig Topper 2017-09-27 22:57:18 +00:00
parent 27f9857973
commit f1654930d1
1 changed files with 22 additions and 16 deletions
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38
lib/Transforms/InstCombine/InstCombineCompares.cpp
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@ -4200,14 +4200,15 @@ Instruction *InstCombiner::foldICmpUsingKnownBits(ICmpInst &I) {
if (Op1Min == Op0Max) // A <u B -> A != B if max(A) == min(B)
return new ICmpInst(ICmpInst::ICMP_NE, Op0, Op1);
if (Op1Min == Op1Max) {
const APInt *CmpC;
if (match(Op1, m_APInt(CmpC))) {
// A <u C -> A == C-1 if min(A)+1 == C
if (Op1Min == Op0Min + 1)
if (*CmpC == Op0Min + 1)
return new ICmpInst(ICmpInst::ICMP_EQ, Op0,
ConstantInt::get(Op0->getType(), Op1Min - 1));
ConstantInt::get(Op1->getType(), *CmpC - 1));
// X <u C --> X == 0, if the number of zero bits in the bottom of X
// exceeds the log2 of C.
if (Op0Known.countMinTrailingZeros() >= Op1Min.ceilLogBase2())
if (Op0Known.countMinTrailingZeros() >= CmpC->ceilLogBase2())
return new ICmpInst(ICmpInst::ICMP_EQ, Op0,
Constant::getNullValue(Op1->getType()));
}
@ -4221,45 +4222,50 @@ Instruction *InstCombiner::foldICmpUsingKnownBits(ICmpInst &I) {
if (Op1Max == Op0Min) // A >u B -> A != B if min(A) == max(B)
return new ICmpInst(ICmpInst::ICMP_NE, Op0, Op1);
if (Op1Min == Op1Max) {
const APInt *CmpC;
if (match(Op1, m_APInt(CmpC))) {
// A >u C -> A == C+1 if max(a)-1 == C
if (Op1Min == Op0Max - 1)
if (*CmpC == Op0Max - 1)
return new ICmpInst(ICmpInst::ICMP_EQ, Op0,
ConstantInt::get(Op1->getType(), Op1Min + 1));
ConstantInt::get(Op1->getType(), *CmpC + 1));
// X >u C --> X != 0, if the number of zero bits in the bottom of X
// exceeds the log2 of C.
if (Op0Known.countMinTrailingZeros() >= Op1Min.getActiveBits())
if (Op0Known.countMinTrailingZeros() >= CmpC->getActiveBits())
return new ICmpInst(ICmpInst::ICMP_NE, Op0,
Constant::getNullValue(Op1->getType()));
}
break;
}
case ICmpInst::ICMP_SLT:
case ICmpInst::ICMP_SLT: {
if (Op0Max.slt(Op1Min)) // A <s B -> true if max(A) < min(C)
return replaceInstUsesWith(I, ConstantInt::getTrue(I.getType()));
if (Op0Min.sge(Op1Max)) // A <s B -> false if min(A) >= max(C)
return replaceInstUsesWith(I, ConstantInt::getFalse(I.getType()));
if (Op1Min == Op0Max) // A <s B -> A != B if max(A) == min(B)
return new ICmpInst(ICmpInst::ICMP_NE, Op0, Op1);
if (Op1Min == Op1Max) { // Constant RHS
if (Op1Min == Op0Min + 1) // A <s C -> A == C-1 if min(A)+1 == C
const APInt *CmpC;
if (match(Op1, m_APInt(CmpC))) {
if (*CmpC == Op0Min + 1) // A <s C -> A == C-1 if min(A)+1 == C
return new ICmpInst(ICmpInst::ICMP_EQ, Op0,
ConstantInt::get(Op1->getType(), Op1Min - 1));
ConstantInt::get(Op1->getType(), *CmpC - 1));
}
break;
case ICmpInst::ICMP_SGT:
}
case ICmpInst::ICMP_SGT: {
if (Op0Min.sgt(Op1Max)) // A >s B -> true if min(A) > max(B)
return replaceInstUsesWith(I, ConstantInt::getTrue(I.getType()));
if (Op0Max.sle(Op1Min)) // A >s B -> false if max(A) <= min(B)
return replaceInstUsesWith(I, ConstantInt::getFalse(I.getType()));
if (Op1Max == Op0Min) // A >s B -> A != B if min(A) == max(B)
return new ICmpInst(ICmpInst::ICMP_NE, Op0, Op1);
if (Op1Min == Op1Max) { // Constant RHS
if (Op1Min == Op0Max - 1) // A >s C -> A == C+1 if max(A)-1 == C
const APInt *CmpC;
if (match(Op1, m_APInt(CmpC))) {
if (*CmpC == Op0Max - 1) // A >s C -> A == C+1 if max(A)-1 == C
return new ICmpInst(ICmpInst::ICMP_EQ, Op0,
ConstantInt::get(Op1->getType(), Op1Min + 1));
ConstantInt::get(Op1->getType(), *CmpC + 1));
}
break;
}
case ICmpInst::ICMP_SGE:
assert(!isa<ConstantInt>(Op1) && "ICMP_SGE with ConstantInt not folded!");
if (Op0Min.sge(Op1Max)) // A >=s B -> true if min(A) >= max(B)