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author | Duncan Sands <baldrick@free.fr> | 2012-11-16 18:55:49 +0000 |
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committer | Duncan Sands <baldrick@free.fr> | 2012-11-16 18:55:49 +0000 |
commit | afe4539f8ea9e12404dce0d67b421d8decb2f0fb (patch) | |
tree | 1fc36cae1e9dc425262cf6075b6465baa9bb8d87 /lib/Transforms | |
parent | 661dfdc9b7e8ea9f65f4af0dca677adc96889773 (diff) | |
download | external_llvm-afe4539f8ea9e12404dce0d67b421d8decb2f0fb.zip external_llvm-afe4539f8ea9e12404dce0d67b421d8decb2f0fb.tar.gz external_llvm-afe4539f8ea9e12404dce0d67b421d8decb2f0fb.tar.bz2 |
Fix PR14361: wrong simplification of A+B==B+A. You may think that the old logic
replaced by this patch is equivalent to the new logic, but you'd be wrong, and
that's exactly where the bug was. There's a similar bug in instsimplify which
manifests itself as instsimplify failing to simplify this, rather than doing it
wrong, see next commit.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168181 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/Transforms')
-rw-r--r-- | lib/Transforms/InstCombine/InstCombineCompares.cpp | 16 |
1 files changed, 14 insertions, 2 deletions
diff --git a/lib/Transforms/InstCombine/InstCombineCompares.cpp b/lib/Transforms/InstCombine/InstCombineCompares.cpp index 8cb4a59..e223a04 100644 --- a/lib/Transforms/InstCombine/InstCombineCompares.cpp +++ b/lib/Transforms/InstCombine/InstCombineCompares.cpp @@ -2356,8 +2356,20 @@ Instruction *InstCombiner::visitICmpInst(ICmpInst &I) { // Try not to increase register pressure. BO0->hasOneUse() && BO1->hasOneUse()) { // Determine Y and Z in the form icmp (X+Y), (X+Z). - Value *Y = (A == C || A == D) ? B : A; - Value *Z = (C == A || C == B) ? D : C; + Value *Y, *Z; + if (A == C) { + Y = B; + Z = D; + } else if (A == D) { + Y = B; + Z = C; + } else if (B == C) { + Y = A; + Z = D; + } else if (B == D) { + Y = A; + Z = C; + } return new ICmpInst(Pred, Y, Z); } |