[all-commits] [llvm/llvm-project] 7e2f1a: Reapply [CHR] Fix up phi nodes with unreachable pr...

[Nikita Popov via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 7e2f1ae7e0ebc7e71ffaa865175aef27fae3b034
      https://github.com/llvm/llvm-project/commit/7e2f1ae7e0ebc7e71ffaa865175aef27fae3b034
  Author: Nikita Popov <npopov at redhat.com>
  Date:   2023-08-16 (Wed, 16 Aug 2023)

  Changed paths:
    M llvm/include/llvm/Analysis/RegionInfoImpl.h
    M llvm/lib/Transforms/Instrumentation/ControlHeightReduction.cpp
    A llvm/test/Transforms/PGOProfile/chr-dead-pred.ll
    R llvm/test/Transforms/StructurizeCFG/AMDGPU/backedge-id-bug-xfail.ll
    M llvm/test/Transforms/StructurizeCFG/AMDGPU/backedge-id-bug.ll

  Log Message:
  -----------
  Reapply [CHR] Fix up phi nodes with unreachable predecessors (PR64594)

Relative to the previous attempt, this also adjusts RegionInfo
verification to allow unreachable predecessors.

-----

If a block in the CHR region has an unreachable predecessor, then
there will be no edge from that predecessor to the newly cloned
block. However, a phi node entry for it will be left behind. Make
sure that these incoming blocks get dropped as well.

Fixes https://github.com/llvm/llvm-project/issues/64594.

Differential Revision: https://reviews.llvm.org/D157621