[all-commits] [llvm/llvm-project] ae14fa: [SCEVExpander] Use stable_sort to sort loop Phis i...

[Dmitry Makogon via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: ae14fae0ff4304022beda5ab484f84ac0fdda807
      https://github.com/llvm/llvm-project/commit/ae14fae0ff4304022beda5ab484f84ac0fdda807
  Author: Dmitry Makogon <d.makogon at g.nsu.ru>
  Date:   2021-11-09 (Tue, 09 Nov 2021)

  Changed paths:
    M llvm/lib/Transforms/Utils/ScalarEvolutionExpander.cpp

  Log Message:
  -----------
  [SCEVExpander] Use stable_sort to sort loop Phis in SCEVExpander::replaceCongruentIVs

This is a fix for test failures on expensive checks build caused by db289340c841990055a164e8eb2a3b5ff25677bf.

With LLVM_ENABLE_EXPENSIVE_CHECKS enabled the llvm::sort shuffles the given container.
However, the sort is only called when the TTI is passed to replaceCongruentIVs.
In the mentioned patch we pass it TTI, so the sort happens. But due to shuffling
equivalent Phis may appear in different order from run to run.
With the stable_sort instead of sort this is impossible - the order of sorted Phis
is preserved.