[all-commits] [llvm/llvm-project] f8a42b: [ADCE] Fix incorrect reporting of CFG changes

[max-azul via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: f8a42bca2812fb602b0f2f24ce60f8216f6ddf87
      https://github.com/llvm/llvm-project/commit/f8a42bca2812fb602b0f2f24ce60f8216f6ddf87
  Author: Max Kazantsev <mkazantsev at azul.com>
  Date:   2020-04-14 (Tue, 14 Apr 2020)

  Changed paths:
    M llvm/lib/Transforms/Scalar/ADCE.cpp
    M llvm/test/Transforms/ADCE/broken-loop-info.ll

  Log Message:
  -----------
  [ADCE] Fix incorrect reporting of CFG changes

This patch fixes 2 related bugs in ADCE:
- `performDeadCodeElimination` does not report changes if it did ONLY
  CFG changes (affects both old and new pass managers);
- When control flow removal is enabled, new pass manager does not
  drop CFG analyses.

Both can lead to incorrect loop info after ADCE that does only CFG changes.

Differential Revision: https://reviews.llvm.org/D78103
Reviewed By: Denis Antrushin