Ahmed Bougacha
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d412c608fc
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[X86] Teach FCOPYSIGN lowering to recognize constant magnitudes.
For code like:
float foo(float x) { return copysign(1.0, x); }
We used to generate:
andps <-0.000000e+00,0,0,0>, %xmm0
movss <1.000000e+00>, %xmm1
andps <nan>, %xmm1
orps %xmm0, %xmm1
Basically doing an abs(1.0f) in the two middle instructions.
We now generate:
andps <-0.000000e+00,0,0,0>, %xmm0
orps <1.000000e+00,0,0,0>, %xmm0
Builds on cleanups r223415, r223542.
rdar://19049548
Differential Revision: http://reviews.llvm.org/D6555
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@225357 91177308-0d34-0410-b5e6-96231b3b80d8
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2015-01-07 17:33:03 +00:00 |
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