[PATCH][X86] Unsafe copysign xform in DAGCombiner

[Demikhovsky, Elena via llvm-commits]

Hi Cameron,

Are you familiar with the review board https://reviews.llvm.org ?
I suggest to upload the patch there.

-  Elena


  |-----Original Message-----
  |From: Cameron McInally [mailto:cameron.mcinally at nyu.edu]
  |Sent: Friday, September 09, 2016 19:25
  |To: llvm-commits at lists.llvm.org
  |Cc: Demikhovsky, Elena <elena.demikhovsky at intel.com>; Breger,
  |Igor <igor.breger at intel.com>; Craig Topper
  |<craig.topper at gmail.com>
  |Subject: [PATCH][X86] Unsafe copysign xform in DAGCombiner
  |
  |Hey guys,
  |
  |There's a copysign xform in the DAGCombiner that replaces safe FP
  |code with unsafe code. Attached is a patch to guard this xform.
  |
  |The issue here (see test case) is the first copysign is removed before
  |the cvt is performed. If the input to the cvt is unordered, it will raise
  |an exception. The purpose of the first copysign is to create a safe
  |value (i.e. 1.0 or -1.0) to feed the cvt.
  |
  |Also, I'm not the most versed in FileCheck. I'd appreciate any critiques
  |on the test case I've added.
  |
  |Thanks,
  |Cam
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