[all-commits] [llvm/llvm-project] a1c05f: [InstCombine] exclude bitcast of ppc_fp128 in icmp...

[RotateRight via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: a1c05fe20f3def1f1be9f50d2adefc6b6f1578ad
      https://github.com/llvm/llvm-project/commit/a1c05fe20f3def1f1be9f50d2adefc6b6f1578ad
  Author: Sanjay Patel <spatel at rotateright.com>
  Date:   2020-04-08 (Wed, 08 Apr 2020)

  Changed paths:
    M llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
    M llvm/test/Transforms/InstCombine/icmp.ll

  Log Message:
  -----------
  [InstCombine] exclude bitcast of ppc_fp128 in icmp signbit fold

Based on the post-commit comments for rG0f56bbc, there might
be a problem with this transform:

(bitcast (fpext/fptrunc X)) to iX) < 0 --> (bitcast X to iY) < 0

...and the ppc_fp128 data type, so conservatively bypass if we
are bitcasting a ppc_fp128.

We might be able to account for endian or other differences to
enable this for PowerPC again if that is useful.

Differential Revision: https://reviews.llvm.org/D77642