[all-commits] [llvm/llvm-project] 41f13f: reland: [DAG] Fix PR45049: LegalizeTypes crash

[Jon Roelofs via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: 41f13f1f64d2074ae7512fb23656c22585e912bd
      https://github.com/llvm/llvm-project/commit/41f13f1f64d2074ae7512fb23656c22585e912bd
  Author: Jonathan Roelofs <jroelofs at jroelofs.com>
  Date:   2020-04-12 (Sun, 12 Apr 2020)

  Changed paths:
    M llvm/lib/CodeGen/SelectionDAG/LegalizeTypes.cpp
    M llvm/lib/CodeGen/SelectionDAG/LegalizeTypes.h
    M llvm/test/CodeGen/X86/legalize-types-remapid.ll

  Log Message:
  -----------
  reland: [DAG] Fix PR45049: LegalizeTypes crash

Sometimes LegalizeTypes knows about common subexpressions before SelectionDAG
does, leading to accidental SDValue removal before its reference count was
truly zero.

Differential Revision: https://reviews.llvm.org/D76994

Reviewed-By: bjope

Fixes: https://bugs.llvm.org/show_bug.cgi?id=45049

Reverted in 3ce77142a6452d76d6f97c9a6c2da193e78841ba because the previous patch
broke the expensive-checks bots. The new patch removes the broken check.