[PATCH] D143762: [AMDGPU] Enable whole wave register copy

[Matt Arsenault via Phabricator via llvm-commits]

arsenm added inline comments.


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Comment at: llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.cpp:1356
+
+  addPass(&SILowerWWMCopiesID);
   return true;
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cdevadas wrote:
> I'm still not convinced why this is needed in the -O0 flow?
> By now, the VGPR allocation is done in the -O0 flow, and we no longer have any virtual registers. This pass act on virtual registers to see if wwm copies needed exec manipulation.
It's conceptually needed and it's an implementation detail of current regalloc fast that these aren't introduced. Plus I think in general we should have other WWM copies for general WWM support in the future


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  https://reviews.llvm.org/D143762/new/

https://reviews.llvm.org/D143762