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

Mon Jul 8 09:56:54 PDT 2019

hliao added a comment.

In D64353#1573837 <https://reviews.llvm.org/D64353#1573837>, @arsenm wrote:

> I don't follow how eliminating unreachable blocks fixes this.
>
> In general expecting code placement with the block "prolog" instructions isn't reliable. I had fixed this in rL357634 <https://reviews.llvm.org/rL357634>, except it was reverted

LCSSA created PHI of flow used by cf.end. These PHIs (due to LCSSA) are unnecessary. `unreachable-mbb-elimination` could remove them.

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D64353/new/

https://reviews.llvm.org/D64353