[all-commits] [llvm/llvm-project] bc1088: DomTree: Make PostDomTree indifferent to block suc...

[Yevgeny Rouban via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: bc10888dcdda1fe80a983029bc50eec4b248cc77
      https://github.com/llvm/llvm-project/commit/bc10888dcdda1fe80a983029bc50eec4b248cc77
  Author: Yevgeny Rouban <yrouban at azul.com>
  Date:   2020-08-05 (Wed, 05 Aug 2020)

  Changed paths:
    M llvm/include/llvm/Support/GenericDomTreeConstruction.h
    A llvm/test/Transforms/InstCombine/infinite-loop-postdom.ll

  Log Message:
  -----------
  DomTree: Make PostDomTree indifferent to block successors swap

Fixed the commit c35585e209efe69e2233bdc5ecd23bed7b735ba3.

This is a fix for the bug 46098 where PostDominatorTree
is unexpectedly changed by InstCombine's branch swapping
transformation.
This patch fixes PostDomTree builder. While looking for
the furthest away node in a reverse unreachable subgraph
this patch runs DFS with successors in their function order.
This order is indifferent to the order of successors, so is
the furthest away node.

Reviewers: kuhar, nikic, lebedev.ri
Differential Revision: https://reviews.llvm.org/D84763