[PATCH][X86] Unsafe copysign xform in DAGCombiner

[Cameron McInally via llvm-commits]

Created D16532 for anyone interested...

On Fri, Sep 9, 2016 at 3:07 PM, Demikhovsky, Elena
<elena.demikhovsky at intel.com> wrote:
> 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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