[all-commits] [llvm/llvm-project] 934211: Add NoOpLoopNestPass and LOOPNEST_PASS macro

[whitneywhtsang via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 93421108d2551f91eb33a8c95bc94661ba953b64
      https://github.com/llvm/llvm-project/commit/93421108d2551f91eb33a8c95bc94661ba953b64
  Author: Whitney Tsang <whitneyt at ca.ibm.com>
  Date:   2021-11-05 (Fri, 05 Nov 2021)

  Changed paths:
    M llvm/lib/Passes/PassBuilder.cpp
    M llvm/lib/Passes/PassRegistry.def
    A llvm/test/Other/loopnest-pass-ordering.ll
    M llvm/test/Other/print-passes.ll

  Log Message:
  -----------
  Add NoOpLoopNestPass and LOOPNEST_PASS macro

Having a NoOpLoopNestPass can ensure that only outermost loop is invoked
for a LoopNestPass with a lit test.

There are some existing passes that are implemented as LoopNestPass, but
they are still using LOOP_PASS macro.
It would be easier to identify LoopNestPasses with a LOOPNEST_PASS
macro.

Differential Revision: https://reviews.llvm.org/D113185