[all-commits] [llvm/llvm-project] 161ccf: [MemorySSA] Pass DT to the upward iterator for pro...

[Alina Sbirlea via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: 161ccfe5bad52aba7518034cea4814aea0906c69
      https://github.com/llvm/llvm-project/commit/161ccfe5bad52aba7518034cea4814aea0906c69
  Author: Alina Sbirlea <asbirlea at google.com>
  Date:   2020-04-29 (Wed, 29 Apr 2020)

  Changed paths:
    M llvm/include/llvm/Analysis/MemorySSA.h
    M llvm/lib/Analysis/MemorySSA.cpp
    M llvm/test/Analysis/MemorySSA/phi-translation.ll

  Log Message:
  -----------
  [MemorySSA] Pass DT to the upward iterator for proper PhiTranslation.

Summary:
A valid DominatorTree is needed to do PhiTranslation.
Before this patch, a MemoryUse could be optimized to an access outside a loop, while the address it loads from is modified in the loop.
This can lead to a miscompile.

Reviewers: george.burgess.iv

Subscribers: Prazek, hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D79068