[all-commits] [llvm/llvm-project] f75564: Reland "[SCEVExpander] Add option to preserve LCSS...

[Florian Hahn via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: f75564ad4e4799465cf14b96f761e3fae13f6976
      https://github.com/llvm/llvm-project/commit/f75564ad4e4799465cf14b96f761e3fae13f6976
  Author: Florian Hahn <flo at fhahn.com>
  Date:   2020-07-29 (Wed, 29 Jul 2020)

  Changed paths:
    M llvm/include/llvm/Transforms/Utils/ScalarEvolutionExpander.h
    M llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp
    M llvm/lib/Transforms/Utils/ScalarEvolutionExpander.cpp
    M llvm/unittests/Transforms/Utils/ScalarEvolutionExpanderTest.cpp
    M polly/lib/Support/ScopHelper.cpp

  Log Message:
  -----------
  Reland "[SCEVExpander] Add option to preserve LCSSA directly."

This reverts the revert commit dc2867576886247cbe351e7c63618c09ab6af808.

It includes a fix for Polly, which uses SCEVExpander on IR that is not
in LCSSA form. Set PreserveLCSSA = false in that case, to ensure we do
not introduce LCSSA phis where there were none before.