[all-commits] [llvm/llvm-project] 17673a: [DAG] Fix PR45049: LegalizeTypes crash

[Jon Roelofs via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: 17673ae0b2cbf8d48973b673d413fb8591d8aae7
      https://github.com/llvm/llvm-project/commit/17673ae0b2cbf8d48973b673d413fb8591d8aae7
  Author: Jonathan Roelofs <jroelofs at jroelofs.com>
  Date:   2020-04-04 (Sat, 04 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:
  -----------
  [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.

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

https://reviews.llvm.org/D76994