[all-commits] [llvm/llvm-project] a25b53: [SCEV] Infer known bits from known sign bits

[Philip Reames via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: a25b537bf437864232cb5826539eb4cee7c47b74
      https://github.com/llvm/llvm-project/commit/a25b537bf437864232cb5826539eb4cee7c47b74
  Author: Philip Reames <listmail at philipreames.com>
  Date:   2021-03-09 (Tue, 09 Mar 2021)

  Changed paths:
    M llvm/lib/Analysis/ScalarEvolution.cpp

  Log Message:
  -----------
  [SCEV] Infer known bits from known sign bits

This was suggested by lebedev.ri over on D96534.  You'll note lack of tests.  During review, we weren't actually able to find a case which exercises it, but both I and lebedev.ri feel it's a reasonable change, straight forward, and near free.

Differential Revision: https://reviews.llvm.org/D97064