[all-commits] [llvm/llvm-project] bb3937: [Indvars][NFCI] Remove meaningless restrictive cod...

[max-azul via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: bb39372e5e66e8d36735fa205d48e06c06a8fa00
      https://github.com/llvm/llvm-project/commit/bb39372e5e66e8d36735fa205d48e06c06a8fa00
  Author: Max Kazantsev <mkazantsev at azul.com>
  Date:   2020-10-16 (Fri, 16 Oct 2020)

  Changed paths:
    M llvm/lib/Transforms/Scalar/IndVarSimplify.cpp

  Log Message:
  -----------
  [Indvars][NFCI] Remove meaningless restrictive code in IndVars

Variable ExtendOperExpr only exists to check whether it is a SCEV ext.
We create it as SCEV ext right here, so semantically this check is
trivially true. In theory, it may fail if SCEV is smart enough and can
simplify the expression. However, no matter whether it is an ext or not,
we never use this fact for further reasoning. So this code is currently
useless and in theory may become harmful with SCEV's development.

We do not expect any behavior changes with removing it. If it caused
negative changes, the patch should be reverted.