[all-commits] [llvm/llvm-project] def15c: [SCEV] Support negative values in signed/unsigned ...

[Max Kazantsev via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: def15c5fb6a117c1b6d8b2835f6760f814410582
      https://github.com/llvm/llvm-project/commit/def15c5fb6a117c1b6d8b2835f6760f814410582
  Author: Max Kazantsev <mkazantsev at azul.com>
  Date:   2021-09-20 (Mon, 20 Sep 2021)

  Changed paths:
    M llvm/lib/Analysis/ScalarEvolution.cpp
    M llvm/test/Transforms/IndVarSimplify/negative_ranges.ll

  Log Message:
  -----------
  [SCEV] Support negative values in signed/unsigned predicate reasoning

There is a piece of logic that uses the fact that signed and unsigned
versions of the same predicate are equivalent when both values are
non-negative. It's also true when both of them are negative.

Differential Revision: https://reviews.llvm.org/D109957
Reviewed By: nikic