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| author | Benjamin Kramer <benny.kra@googlemail.com> | 2011-03-11 14:46:49 +0000 |
|---|---|---|
| committer | Benjamin Kramer <benny.kra@googlemail.com> | 2011-03-11 14:46:49 +0000 |
| commit | 2715a581494ef0c7f7403f9f7dbe4c0d052d61a5 (patch) | |
| tree | 7f38e96b0239c201408a83a0b4c2b20b579d921b /lib/Analysis/ValueTracking.cpp | |
| parent | 6b4972518cff5b0f76ec63fc8b93b74ae64c3f3d (diff) | |
ComputeMaskedBits: sub falls through to add, and sub doesn't have the same overflow semantics as add.
Should fix the selfhost failures that started with r127463.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127465 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/Analysis/ValueTracking.cpp')
| -rw-r--r-- | lib/Analysis/ValueTracking.cpp | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/lib/Analysis/ValueTracking.cpp b/lib/Analysis/ValueTracking.cpp index 33fb1e8cdc..6c33d2d508 100644 --- a/lib/Analysis/ValueTracking.cpp +++ b/lib/Analysis/ValueTracking.cpp @@ -431,7 +431,8 @@ void llvm::ComputeMaskedBits(Value *V, const APInt &Mask, } // Are we still trying to solve for the sign bit? - if (Mask.isNegative() && !KnownZero.isNegative() && !KnownOne.isNegative()){ + if (I->getOpcode() == Instruction::Add && + Mask.isNegative() && !KnownZero.isNegative() && !KnownOne.isNegative()){ OverflowingBinaryOperator *OBO = cast<OverflowingBinaryOperator>(I); if (OBO->hasNoSignedWrap()) { // Adding two positive numbers can't wrap into negative ... |