[all-commits] [llvm/llvm-project] 952ad4: [ValueTracking] Let isGuaranteedNotToBeUndefOrPois...

[Juneyoung Lee via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: 952ad4701cf0d8da79789f6b83ddaa386c60d535
      https://github.com/llvm/llvm-project/commit/952ad4701cf0d8da79789f6b83ddaa386c60d535
  Author: Juneyoung Lee <aqjune at gmail.com>
  Date:   2020-03-04 (Wed, 04 Mar 2020)

  Changed paths:
    M llvm/include/llvm/Analysis/ValueTracking.h
    M llvm/lib/Analysis/InstructionSimplify.cpp
    M llvm/lib/Analysis/ValueTracking.cpp
    M llvm/test/Transforms/InstSimplify/freeze.ll

  Log Message:
  -----------
  [ValueTracking] Let isGuaranteedNotToBeUndefOrPoison look into branch conditions of dominating blocks' terminators

Summary:
```
  br i1 c, BB1, BB2:
BB1:
  use1(c)
BB2:
  use2(c)
```

In BB1 and BB2, c is never undef or poison because otherwise the branch would have triggered UB.

Checked with Alive2

Reviewers: xbolva00, spatel, lebedev.ri, reames, jdoerfert, nlopes, sanjoy

Reviewed By: reames

Subscribers: jdoerfert, hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D75401