[PATCH] D64353: [AMDGPU] Run '' after isel to simplify PHIs.

Mon Jul 8 11:05:41 PDT 2019

hliao added a comment.

In D64353#1573922 <https://reviews.llvm.org/D64353#1573922>, @arsenm wrote:

> I think you should probably fix SILowerControlFlow

the misplacement of def/use is not the fault of SILowerControlFlow but PHIEliminate. However, even PHIEliminate should not be blamed as cf.end is part of MBB prologue. cf.end should not take any input from PHI.

In O2 <https://reviews.llvm.org/owners/package/2/> compilation, there won't be such issue as, in optimized RA, livevariable is used to eliminate PHI better. LiveVariables depends on unreachable-mbb-elimin, which remove the PHI to cf.end.

Repository:
  rG LLVM Github Monorepo

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https://reviews.llvm.org/D64353