[PATCH] D92219: [AMDGPU][GlobalISel] Avoid selecting S_PACK with constants

[Mirko Brkusanin via Phabricator via llvm-commits]

mbrkusanin updated this revision to Diff 308027.
mbrkusanin retitled this revision from "[AMDGPU] Constant fold S_PACK instructions" to "[AMDGPU][GlobalISel] Avoid selecting S_PACK with constants".
mbrkusanin edited the summary of this revision.
mbrkusanin added a comment.
Herald added a subscriber: rovka.

Specific case from one of the tests:

  %5:sgpr(s16) = G_FCONSTANT half 0xH4000
  %7:sgpr(s32) = G_ANYEXT %5:sgpr(s16)
  %4:sreg_32(<2 x s16>) = G_BUILD_VECTOR_TRUNC %7:sgpr(s32), %7:sgpr(s32)

will now be:

  %4:sreg_32 = S_MOV_B32 1073758208

instead of:

  %5:sreg_32 = S_MOV_B32 16384
  %4:sreg_32 = S_PACK_LL_B32_B16 %5:sreg_32, %5:sreg_32


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D92219/new/

https://reviews.llvm.org/D92219

Files:
  llvm/include/llvm/CodeGen/GlobalISel/Utils.h
  llvm/lib/CodeGen/GlobalISel/Utils.cpp
  llvm/lib/Target/AMDGPU/AMDGPUInstructionSelector.cpp
  llvm/test/CodeGen/AMDGPU/GlobalISel/inst-select-build-vector-trunc.v2s16.mir
  llvm/test/CodeGen/AMDGPU/GlobalISel/llvm.amdgcn.fdot2.ll

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