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| author | Hal Finkel <hfinkel@anl.gov> | 2013-07-09 18:16:16 +0000 |
|---|---|---|
| committer | Hal Finkel <hfinkel@anl.gov> | 2013-07-09 18:16:16 +0000 |
| commit | ff666bd962a4446d80955fe75619201c29795501 (patch) | |
| tree | 3d97fd8d78031aa12d48ffc0e00578b97d242b99 /llvm/lib/Analysis/ScalarEvolution.cpp | |
| parent | a92b3c914ebb356aec22c978eae9fa9543fa62e6 (diff) | |
| download | bcm5719-llvm-ff666bd962a4446d80955fe75619201c29795501.tar.gz bcm5719-llvm-ff666bd962a4446d80955fe75619201c29795501.zip | |
Don't crash in SE dealing with ashr x, -1
ScalarEvolution::getSignedRange uses ComputeNumSignBits from ValueTracking on
ashr instructions. ComputeNumSignBits can return zero, but this case was not
handled correctly by the code in getSignedRange which was calling:
APInt::getSignedMinValue(BitWidth).ashr(NS - 1)
with NS = 0, resulting in an assertion failure in APInt::ashr.
Now, we just return the conservative result (as with NS == 1).
Another bug found by llvm-stress.
llvm-svn: 185955
Diffstat (limited to 'llvm/lib/Analysis/ScalarEvolution.cpp')
| -rw-r--r-- | llvm/lib/Analysis/ScalarEvolution.cpp | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/llvm/lib/Analysis/ScalarEvolution.cpp b/llvm/lib/Analysis/ScalarEvolution.cpp index 0bff21e7c3e..af5051650ee 100644 --- a/llvm/lib/Analysis/ScalarEvolution.cpp +++ b/llvm/lib/Analysis/ScalarEvolution.cpp @@ -3589,7 +3589,7 @@ ScalarEvolution::getSignedRange(const SCEV *S) { if (!U->getValue()->getType()->isIntegerTy() && !TD) return setSignedRange(U, ConservativeResult); unsigned NS = ComputeNumSignBits(U->getValue(), TD); - if (NS == 1) + if (NS <= 1) return setSignedRange(U, ConservativeResult); return setSignedRange(U, ConservativeResult.intersectWith( ConstantRange(APInt::getSignedMinValue(BitWidth).ashr(NS - 1), |
