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| author | Sanjay Patel <spatel@rotateright.com> | 2014-12-31 22:14:05 +0000 |
|---|---|---|
| committer | Sanjay Patel <spatel@rotateright.com> | 2014-12-31 22:14:05 +0000 |
| commit | e68f71574f9c61f72d1aca2811d85da9e4bc0a69 (patch) | |
| tree | 542273ea5e87168e9ec96a46f80efb3c267b688c /llvm/test | |
| parent | 0dfd2400688266e688c00b62b38491d4a297c20c (diff) | |
| download | bcm5719-llvm-e68f71574f9c61f72d1aca2811d85da9e4bc0a69.tar.gz bcm5719-llvm-e68f71574f9c61f72d1aca2811d85da9e4bc0a69.zip | |
InstCombine: fsub nsz 0, X ==> fsub nsz -0.0, X
Some day the backend may handle instruction-level fast math flags and make
this transform unnecessary, but it's still better practice to use the canonical
representation of fneg when possible (use a -0.0).
This is a partial fix for PR20870 ( http://llvm.org/bugs/show_bug.cgi?id=20870 ).
See also http://reviews.llvm.org/D6723.
Differential Revision: http://reviews.llvm.org/D6731
llvm-svn: 225050
Diffstat (limited to 'llvm/test')
| -rw-r--r-- | llvm/test/Transforms/InstCombine/fast-math.ll | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/llvm/test/Transforms/InstCombine/fast-math.ll b/llvm/test/Transforms/InstCombine/fast-math.ll index f39adba6560..c6081c39925 100644 --- a/llvm/test/Transforms/InstCombine/fast-math.ll +++ b/llvm/test/Transforms/InstCombine/fast-math.ll @@ -322,6 +322,14 @@ define float @fneg1(float %f1, float %f2) { ; CHECK: fmul float %f1, %f2 } +define float @fneg2(float %x) { + %sub = fsub nsz float 0.0, %x + ret float %sub +; CHECK-LABEL: @fneg2( +; CHECK-NEXT: fsub nsz float -0.000000e+00, %x +; CHECK-NEXT: ret float +} + ; ========================================================================= ; ; Testing-cases about div |
