[all-commits] [llvm/llvm-project] 242961: [llvm][fix-irreducible] ensure that loop subtree u...

[Sun Ziping via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 242961f23b4abaca999611fd364e93a8d2186371
      https://github.com/llvm/llvm-project/commit/242961f23b4abaca999611fd364e93a8d2186371
  Author: Sun Ziping <me at szp.io>
  Date:   2022-05-18 (Wed, 18 May 2022)

  Changed paths:
    M llvm/lib/Transforms/Utils/FixIrreducible.cpp

  Log Message:
  -----------
  [llvm][fix-irreducible] ensure that loop subtree under child is correctly reconnected to new loop

The modified function was incorrectly (not unnecessarily) ignoring grandchild
loops, and this change fixes the bug. In particular, this fixes the handling of
the loop { inner, body }. The TODO in the same function is talking about the b1
self loop, which may be "unnecessarily" lost, but that is a different issue.