diff options
| author | David Green <david.green@arm.com> | 2019-11-30 14:20:55 +0000 |
|---|---|---|
| committer | David Green <david.green@arm.com> | 2019-11-30 16:58:00 +0000 |
| commit | 3a1bef5616c3eb466b5f8a076385ee09e5a9ad9a (patch) | |
| tree | 8679997f135350af218461b587b98a58961ea8c5 /llvm/lib/Transforms | |
| parent | a46b959ebd605e9dc4bc0e041dac3bdf2f3d8989 (diff) | |
| download | bcm5719-llvm-3a1bef5616c3eb466b5f8a076385ee09e5a9ad9a.tar.gz bcm5719-llvm-3a1bef5616c3eb466b5f8a076385ee09e5a9ad9a.zip | |
[InstCombine] Adjust usub_sat fold one use checks
This adjusts the one use checks in the the usub_sat fold code to not
increase instruction count, but otherwise do the fold. Reviewed as a
part of D69514.
Diffstat (limited to 'llvm/lib/Transforms')
| -rw-r--r-- | llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp b/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp index bdfbd75d31a..0b6b7c3c66d 100644 --- a/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp +++ b/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp @@ -711,9 +711,9 @@ static Value *canonicalizeSaturatedSubtract(const ICmpInst *ICI, else if (!match(TrueVal, m_Sub(m_Specific(A), m_Specific(B)))) return nullptr; - // If sub is used anywhere else, we wouldn't be able to eliminate it - // afterwards. - if (!TrueVal->hasOneUse()) + // If we are adding a negate and the sub and icmp are used anywhere else, we + // would end up with more instructions. + if (IsNegative && !TrueVal->hasOneUse() && !ICI->hasOneUse()) return nullptr; // (a > b) ? a - b : 0 -> usub.sat(a, b) |
