[all-commits] [llvm/llvm-project] d46d96: [BBUtils] Don't add 'then' block to a loop if it's...

[Dmitry Makogon via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: d46d9689f7c3fe16010cd07761858a6392239b3f
      https://github.com/llvm/llvm-project/commit/d46d9689f7c3fe16010cd07761858a6392239b3f
  Author: Dmitry Makogon <d.makogon at g.nsu.ru>
  Date:   2023-06-19 (Mon, 19 Jun 2023)

  Changed paths:
    M llvm/lib/Transforms/Utils/BasicBlockUtils.cpp
    M llvm/test/Transforms/SimpleLoopUnswitch/guards.ll
    M llvm/test/Transforms/SimpleLoopUnswitch/nontrivial-unswitch-skip-selects-in-guards.ll

  Log Message:
  -----------
  [BBUtils] Don't add 'then' block to a loop if it's terminated with unreachable

SplitBlockAndInsertIfThen utility creates two new blocks,
they're called ThenBlock and Tail (true and false destinations of a conditional
branch correspondingly). The function has a bool parameter Unreachable,
and if it's set, then ThenBlock is terminated with an unreachable.
At the end of the function the new blocks are added to the loop of the split
block. However, in case ThenBlock is terminated with an unreachable,
it cannot belong to any loop.

Differential Revision: https://reviews.llvm.org/D152434