[PATCH] D101992: AMDGPU/GlobalISel: Use destination register bank in applyMappingLoad

Fri May 7 03:20:02 PDT 2021

Petar.Avramovic added inline comments.

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Comment at: llvm/test/CodeGen/AMDGPU/GlobalISel/load-constant.96.ll:449-452
+; GFX7-UNALIGNED-NEXT:    s_mov_b32 s2, -1
+; GFX7-UNALIGNED-NEXT:    s_mov_b32 s3, 0xf000
+; GFX7-UNALIGNED-NEXT:    buffer_load_dwordx3 v[0:2], off, s[0:3], 0
+; GFX7-UNALIGNED-NEXT:    s_waitcnt vmcnt(0)
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foad wrote:
> arsenm wrote:
> > This looks like an accidental bug fix
> Why is it a bug fix? Isn't it better to use a scalar load when possible, cos it's less memory traffic?
It is a silent bug, that load was marked as vgpr dest, and then split into two sgpr dest loads (was meant to be one buffer load according to banks assigned before applyMapping)

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  https://reviews.llvm.org/D101992/new/

https://reviews.llvm.org/D101992