[all-commits] [llvm/llvm-project] 484c62: [SCEV] Do not strengthen nuw/nsw flags during get[...

[Florian Hahn via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 484c622760e2a46aa1b52c7a791ee59543364225
      https://github.com/llvm/llvm-project/commit/484c622760e2a46aa1b52c7a791ee59543364225
  Author: Florian Hahn <flo at fhahn.com>
  Date:   2023-03-15 (Wed, 15 Mar 2023)

  Changed paths:
    M llvm/lib/Analysis/ScalarEvolution.cpp
    M llvm/test/Transforms/IndVarSimplify/lftr-reuse.ll

  Log Message:
  -----------
  [SCEV] Do not strengthen nuw/nsw flags during get[Zero,Sign]ExtendedExpr.

Modifying AddRecs when constructing other expressions can lead to
surprising changes. It also seems like it is not really beneficial i
most cases.

At the moment, there's a single regression, but we still might be able
to improve the flags at AddRec construction.

Might help with the issue discussed in D143409.

Reviewed By: mkazantsev

Differential Revision: https://reviews.llvm.org/D144051