[PATCH] D25991: [PPC] Peephole to remove extra fcmp that checks for NaN

[Ehsan Amiri via llvm-commits]

amehsan created this revision.
amehsan added reviewers: kbarton, hfinkel, nemanjai, echristo, jtony, syzaara, sfertile.
amehsan added a subscriber: llvm-commits.
Herald added a subscriber: mehdi_amini.

The functionality is explained in a comment in the patch. So I do not repeat that here.

This problem is exposed after a patch that I recently committed to generate +0.0 using xor, instead of loading it from constant area. Currently this is a targetted fix for this particular pattern. I tried a little to create other testcases with a similar problem, but that was not successful. If you have ideas for generalizing the patch, I can update it.


https://reviews.llvm.org/D25991

Files:
  lib/Target/PowerPC/PPCInstrInfo.cpp
  lib/Target/PowerPC/PPCInstrInfo.h
  test/CodeGen/PowerPC/fast-isel-fcmp-nan.ll

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