[all-commits] [llvm/llvm-project] bc4307: [LoopFlatten] Fix bug where SCEVCouldNotCompute ob...

[sjoerdmeijer via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: bc43078fe835e19782a90ad2f464ebdc150911de
      https://github.com/llvm/llvm-project/commit/bc43078fe835e19782a90ad2f464ebdc150911de
  Author: Sjoerd Meijer <sjoerd.meijer at arm.com>
  Date:   2021-07-28 (Wed, 28 Jul 2021)

  Changed paths:
    M llvm/lib/Transforms/Scalar/LoopFlatten.cpp
    M llvm/test/Transforms/LoopFlatten/loop-flatten-negative.ll

  Log Message:
  -----------
  [LoopFlatten] Fix bug where SCEVCouldNotCompute object is used

The SCEV method getBackedgeTakenCount() returns a SCEVCouldNotCompute
object if the backedge-taken count is unpredictable. This fix ensures
there is no longer an attempt to use such an object to find the trip
count.

Patch by: Rosie Sumpter.

Differential Revision: https://reviews.llvm.org/D106970