[PATCH] D109301: [AMDGPU] Enable copy between VGPR and AGPR classes during regalloc
Christudasan Devadasan via Phabricator via llvm-commits
llvm-commits at lists.llvm.org
Tue Nov 16 01:43:46 PST 2021
cdevadas added a comment.
> In fact restoring into av superclass also seems problematic. I believe we have agreed all the code here only work correctly if we have no actual av registers past selection.
The function `getLargestLegalSuperClass` is used mainly during Greedy, coalescer, and spiller.
Restore to AV class is part of the Spiller during regalloc. In this patch, I made a fix in `storeRegToStackSlot` to convert superclass spills into VGPR spills by introducing a copy.
AV classes appear only in COPY instances and they all become either VGPRs or AGPRs after `virtregrewriter`.
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https://reviews.llvm.org/D109301/new/
https://reviews.llvm.org/D109301
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