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| author | Yingwei Zheng <dtcxzyw2333@gmail.com> | 2024-05-20 21:52:38 +0800 |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2024-05-20 21:52:38 +0800 |
| commit | 04ae6e600a3090ccc1f80d0110a1108aa73a54f8 (patch) | |
| tree | 67341424cec4d0387b277cbf3c27fbe6f88c38b8 /llvm/lib/Analysis/ValueTracking.cpp | |
| parent | 36899d693d91719e7e6cd0f0ee4cf579111b8509 (diff) | |
| download | llvm-04ae6e600a3090ccc1f80d0110a1108aa73a54f8.zip llvm-04ae6e600a3090ccc1f80d0110a1108aa73a54f8.tar.gz llvm-04ae6e600a3090ccc1f80d0110a1108aa73a54f8.tar.bz2 | |
[ValueTracking] Fix incorrect inferrence about the signbit of sqrt (#92510)
According to IEEE Std 754-2019, `sqrt` returns nan when the input is
negative (except for -0). In this case, we cannot make assumptions about
sign bit of the result.
Fixes https://github.com/llvm/llvm-project/issues/92217
Diffstat (limited to 'llvm/lib/Analysis/ValueTracking.cpp')
| -rw-r--r-- | llvm/lib/Analysis/ValueTracking.cpp | 5 |
1 files changed, 1 insertions, 4 deletions
diff --git a/llvm/lib/Analysis/ValueTracking.cpp b/llvm/lib/Analysis/ValueTracking.cpp index 2d1486d..063162e 100644 --- a/llvm/lib/Analysis/ValueTracking.cpp +++ b/llvm/lib/Analysis/ValueTracking.cpp @@ -4940,11 +4940,8 @@ void computeKnownFPClass(const Value *V, const APInt &DemandedElts, // subnormal input could produce a negative zero output. const Function *F = II->getFunction(); if (Q.IIQ.hasNoSignedZeros(II) || - (F && KnownSrc.isKnownNeverLogicalNegZero(*F, II->getType()))) { + (F && KnownSrc.isKnownNeverLogicalNegZero(*F, II->getType()))) Known.knownNot(fcNegZero); - if (KnownSrc.isKnownNeverNaN()) - Known.signBitMustBeZero(); - } break; } |