[all-commits] [llvm/llvm-project] 22ebbc: LoopUnrollAndJam] Only allow loops with single exi...

[Sidharth Baveja via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 22ebbc47655737eb543c8641b2e8491846b3aefb
      https://github.com/llvm/llvm-project/commit/22ebbc47655737eb543c8641b2e8491846b3aefb
  Author: Sidharth Baveja <sidharth.baveja at ibm.com>
  Date:   2021-02-05 (Fri, 05 Feb 2021)

  Changed paths:
    M llvm/lib/Transforms/Utils/LoopUnrollAndJam.cpp
    A llvm/test/Transforms/LoopUnrollAndJam/multiple_exit_blocks.ll

  Log Message:
  -----------
  LoopUnrollAndJam] Only allow loops with single exit(ing) blocks

Summary:
This resolves an issue posted on Bugzilla. https://bugs.llvm.org/show_bug.cgi?id=48764
In this issue, the loop had  multiple exit blocks, which resulted in the
function getExitBlock to return a nullptr, which resulted in hitting the assert.
This patch ensures that loops which only have one exit block as allowed to be
unrolled and jammed.

Reviewed By: Whitney, Meinersbur, dmgreen

Differential Revision: https://reviews.llvm.org/D95806