[all-commits] [llvm/llvm-project] 764d9a: Recommit "[SCEV] Look through single value PHIs." ...

[Florian Hahn via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 764d9aa97905f202385b4f25f8d234630b4feef3
      https://github.com/llvm/llvm-project/commit/764d9aa97905f202385b4f25f8d234630b4feef3
  Author: Florian Hahn <flo at fhahn.com>
  Date:   2021-09-28 (Tue, 28 Sep 2021)

  Changed paths:
    M llvm/lib/Analysis/ScalarEvolution.cpp
    M llvm/test/Analysis/DependenceAnalysis/lcssa.ll
    M llvm/test/Analysis/ScalarEvolution/incorrect-exit-count.ll
    M llvm/test/Analysis/ScalarEvolution/solve-quadratic-i1.ll
    M llvm/test/Analysis/ScalarEvolution/solve-quadratic-overflow.ll
    M llvm/test/Transforms/LoopStrengthReduce/funclet.ll
    M llvm/test/Transforms/LoopVectorize/pr45259.ll

  Log Message:
  -----------
  Recommit "[SCEV] Look through single value PHIs." (take 2)

This reverts commit 8fdac7cb7abbeeaed016ef9eb7a087458e41e33f.

The issue causing the revert has been fixed a while ago in 60b852092c98.

Original message:

    Now that SCEVExpander can preserve LCSSA form,
    we do not have to worry about LCSSA form when
    trying to look through PHIs. SCEVExpander will take
    care of inserting LCSSA PHI nodes as required.

    This increases precision of the analysis in some cases.

    Reviewed By: mkazantsev, bmahjour

    Differential Revision: https://reviews.llvm.org/D71539