[PATCH] D149651: [UnreachableBlockElim] Don't remove LCSSA phi nodes

[Pierre van Houtryve via Phabricator via llvm-commits]

Pierre-vh added inline comments.


================
Comment at: llvm/lib/Target/AMDGPU/SILowerControlFlow.cpp:430-431
           .add(MI.getOperand(0));
+  if (LV)
+    LV->replaceKillInstruction(MI.getOperand(0).getReg(), MI, *AndN2);
 
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foad wrote:
> I can submit this separately, but I guess I would have to come up with a MIR test case. I am not sure why the change to UnreachableBlockElim exposed this problem.
No strong opinion on leaving this in this patch or splitting it up, but it would be nice to have a MIR testcase just for this fix IMO (with `-run-pass` or `-start-before`). 

Maybe you can quickly get one by using `-stop-before` + `llvm-reduce` & some manual cleanup on the test that was previously failing?


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D149651/new/

https://reviews.llvm.org/D149651