[all-commits] [llvm/llvm-project] 4a8dbc: [SSAUpdater] Don't call ValueIsRAUWd upon single u...

[Daniil Suchkov via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: 4a8dbc617d0b28ce2ce3e6856376b3802409554e
      https://github.com/llvm/llvm-project/commit/4a8dbc617d0b28ce2ce3e6856376b3802409554e
  Author: Daniil Suchkov <suc-daniil at yandex.ru>
  Date:   2020-01-23 (Thu, 23 Jan 2020)

  Changed paths:
    M llvm/lib/Transforms/Utils/SSAUpdater.cpp
    M llvm/test/Transforms/LCSSA/pr44320.ll

  Log Message:
  -----------
  [SSAUpdater] Don't call ValueIsRAUWd upon single use replacement

It is incorrect to call ValueHandleBase::ValueIsRAUWd when only one use
is replaced since it simply violates semantics of the callback and leads
to bugs like PR44320.

Previously this call was used specifically to keep LICM's cache of
AliasSetTrackers up to date across passes (as PR36801 showed, even for
that purpose it didn't work properly), but since LICM doesn't have that
cache anymore, we can safely remove this incorrect call with no
repercussions.

This patch fixes https://bugs.llvm.org/show_bug.cgi?id=44320

Reviewers: asbirlea, fhahn, efriedma, reames

Reviewed-By: asbirlea

Differential Revision: https://reviews.llvm.org/D73089