[all-commits] [llvm/llvm-project] 05b44f: [LCSSA] Provide option for caller to clean up unus...

[Florian Hahn via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: 05b44f7eaebfbca19999fde149c4c586fc965015
      https://github.com/llvm/llvm-project/commit/05b44f7eaebfbca19999fde149c4c586fc965015
  Author: Florian Hahn <flo at fhahn.com>
  Date:   2020-08-01 (Sat, 01 Aug 2020)

  Changed paths:
    M llvm/include/llvm/Transforms/Utils/LoopUtils.h
    M llvm/lib/Transforms/Utils/LCSSA.cpp
    M llvm/lib/Transforms/Utils/ScalarEvolutionExpander.cpp
    A llvm/test/CodeGen/PowerPC/hardware-loops-crash.ll

  Log Message:
  -----------
  [LCSSA] Provide option for caller to clean up unused PHIs.

formLCSSAForInstructions is used by SCEVExpander, which tracks all
inserted instructions including LCSSA phis using asserting value
handles. This means cleanup needs to happen in the caller.

Extend formLCSSAForInstructions  to take an optional pointer to a
vector. If this argument is non-nullptr, instead of directly deleting
the phis, add them to the vector, so the caller can process them.

This should address various PPC buildbot failures, including
http://lab.llvm.org:8011/builders/clang-ppc64be-linux-lnt/builds/40567