[all-commits] [llvm/llvm-project] 6a8237: Special case common branch patterns in breakLoopBa...

[Philip Reames via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 6a82376012f519b6ef630a662d7b1e204e638eff
      https://github.com/llvm/llvm-project/commit/6a82376012f519b6ef630a662d7b1e204e638eff
  Author: Philip Reames <listmail at philipreames.com>
  Date:   2021-08-27 (Fri, 27 Aug 2021)

  Changed paths:
    M llvm/lib/Transforms/Utils/LoopUtils.cpp
    M llvm/test/Transforms/IndVarSimplify/exit_value_test2.ll
    M llvm/test/Transforms/LoopDeletion/eval_first_iteration.ll
    M llvm/test/Transforms/LoopDeletion/loops-with-irreducible-subloops.ll
    M llvm/test/Transforms/LoopDeletion/noop-loops-with-subloops.ll
    M llvm/test/Transforms/LoopDeletion/pr49967.ll
    M llvm/test/Transforms/LoopDeletion/unreachable-loops.ll
    M llvm/test/Transforms/LoopDeletion/zero-btc.ll

  Log Message:
  -----------
  Special case common branch patterns in breakLoopBackedge (try 2)

Changes since aec08e:
* Adjust placement of a closing brace so that the general case actually runs.  Turns out we had *no* coverage of the switch case.  I added one in eae90fd.
* Drop .llvm.loop.* metadata from the new branch as there is no longer a loop to annotate.

Original commit message:

This special cases an unconditional latch and a conditional branch latch exit to improve codegen and test readability. I am hoping to reuse this function in the runtime unroll code, but without this change, the test diffs are far too complex to assess.