diff options
| author | Reid Kleckner <reid@kleckner.net> | 2014-03-27 17:49:27 +0000 |
|---|---|---|
| committer | Reid Kleckner <reid@kleckner.net> | 2014-03-27 17:49:27 +0000 |
| commit | 3bdf9bc48b9e2b678882ade29ee1fb4db69f134c (patch) | |
| tree | 1e35dcaee0866c875c48c4de716e7e8df5789f04 /llvm/lib/Transforms | |
| parent | 3a571019c8b17e6f5896c5b2a80e3a854011eb32 (diff) | |
| download | bcm5719-llvm-3bdf9bc48b9e2b678882ade29ee1fb4db69f134c.tar.gz bcm5719-llvm-3bdf9bc48b9e2b678882ade29ee1fb4db69f134c.zip | |
InstCombine: Don't combine constants on unsigned icmps
Fixes a miscompile introduced in r204912. It would miscompile code like
(unsigned)(a + -49) <= 5U. The transform would turn this into
(unsigned)a < 55U, which would return true for values in [0, 49], when
it should not.
llvm-svn: 204948
Diffstat (limited to 'llvm/lib/Transforms')
| -rw-r--r-- | llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp index 9bf38189542..fea0d0245c8 100644 --- a/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp +++ b/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp @@ -3010,7 +3010,8 @@ Instruction *InstCombiner::visitICmpInst(ICmpInst &I) { return FoldICmpAddOpCst(I, X, Cst, I.getSwappedPredicate()); ConstantInt *Cst2; - if (match(Op1, m_ConstantInt(Cst)) && + if (I.isSigned() && + match(Op1, m_ConstantInt(Cst)) && match(Op0, m_Add(m_Value(X), m_ConstantInt(Cst2))) && cast<BinaryOperator>(Op0)->hasNoSignedWrap()) { // icmp X+Cst2, Cst --> icmp X, Cst-Cst2 |
