[PATCH] D28004: AMDGPU: Invert cmp + select with constant

[Matt Arsenault via Phabricator via llvm-commits]

arsenm created this revision.
arsenm added a subscriber: llvm-commits.
Herald added a reviewer: tstellarAMD.
Herald added subscribers: tony-tye, yaxunl, nhaehnle, wdng, kzhuravl.

Canonicalize a select with a constant to the false side. This
enables more instruction shrinking opportunities since an
inline immediate can be used for the false side of v_cndmask_b32_e32.

      

This seems to usually be better but causes some code size regressions
in some tests.


https://reviews.llvm.org/D28004

Files:
  lib/Target/AMDGPU/AMDGPUISelLowering.cpp
  test/CodeGen/AMDGPU/ctlz.ll
  test/CodeGen/AMDGPU/select-fabs-fneg-extract.ll
  test/CodeGen/AMDGPU/select.f16.ll
  test/CodeGen/AMDGPU/v_cndmask.ll

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