From b0884f3f13ca6e5d83e3232d8390a4d58739d57c Mon Sep 17 00:00:00 2001 From: Benjamin Kramer Date: Thu, 28 Apr 2011 21:38:51 +0000 Subject: [PATCH] We require threse bits to be zero, too. This shouldn't happen in practice because the icmp would be a constant. Add a check so we don't miscompile code if something goes wrong. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@130446 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Transforms/InstCombine/InstCombineAndOrXor.cpp | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp b/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp index 75e93127e7e..a08446e5d51 100644 --- a/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp +++ b/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp @@ -772,7 +772,7 @@ Value *InstCombiner::FoldAndOfICmps(ICmpInst *LHS, ICmpInst *RHS) { // (trunc x) == C1 & (and x, CA) == C2 -> (and x, CA|CMAX) == C1|C2 // where CMAX is the all ones value for the truncated type, - // iff the lower bits of CA are zero. + // iff the lower bits of C2 and CA are zero. if (LHSCC == RHSCC && ICmpInst::isEquality(LHSCC) && LHS->hasOneUse() && RHS->hasOneUse()) { Value *V; @@ -797,7 +797,7 @@ Value *InstCombiner::FoldAndOfICmps(ICmpInst *LHS, ICmpInst *RHS) { // Check that the low bits are zero. APInt Low = APInt::getLowBitsSet(BigBitSize, SmallBitSize); - if ((Low & AndCst->getValue()) == 0) { + if ((Low & AndCst->getValue()) == 0 && (Low & BigCst->getValue()) == 0) { Value *NewAnd = Builder->CreateAnd(V, Low | AndCst->getValue()); APInt N = SmallCst->getValue().zext(BigBitSize) | BigCst->getValue(); Value *NewVal = ConstantInt::get(AndCst->getType()->getContext(), N); -- 2.34.1