[PATCH] D96980: [amdgpu] Revert agnostic SGPR spill.

[Michael Liao via Phabricator via llvm-commits]

hliao added inline comments.


================
Comment at: llvm/lib/Target/AMDGPU/SIInstrInfo.cpp:3316
+  }
+
   return false;
----------------
critson wrote:
> This seems reasonable.
> It avoids the case where an EXEC=0 region attempts to restore an SGPR for immediate use in the same region.
> I guess we are assuring ourselves that semantically an EXEC=0 region never restores an SGPR expecting it to be live beyond that region?
> (And that EXEC=0 regions will never save SGPRs expecting them to have meaningful effects elsewhere.)
> This seems reasonable.
> It avoids the case where an EXEC=0 region attempts to restore an SGPR for immediate use in the same region.
> I guess we are assuring ourselves that semantically an EXEC=0 region never restores an SGPR expecting it to be live beyond that region?
> (And that EXEC=0 regions will never save SGPRs expecting them to have meaningful effects elsewhere.)

So that, it means technically, we won't have EXEC = 0 case at all, right?


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  https://reviews.llvm.org/D96980/new/

https://reviews.llvm.org/D96980