[all-commits] [llvm/llvm-project] bb939e: [BasicAA] Handle known non-zero variable index

[Nikita Popov via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: bb939ebfd7f48a1aa744941d6de86e69d3796b5d
      https://github.com/llvm/llvm-project/commit/bb939ebfd7f48a1aa744941d6de86e69d3796b5d
  Author: Nikita Popov <nikita.ppv at gmail.com>
  Date:   2020-12-13 (Sun, 13 Dec 2020)

  Changed paths:
    M llvm/lib/Analysis/BasicAliasAnalysis.cpp
    M llvm/test/Analysis/BasicAA/bug.23626.ll
    M llvm/test/Analysis/BasicAA/sequential-gep.ll

  Log Message:
  -----------
  [BasicAA] Handle known non-zero variable index

BasicAA currently handles cases like Scale*V0 + (-Scale)*V1 where
V0 != V1, but does not handle the simpler case of Scale*V with
V != 0. Add it based on an isKnownNonZero() call.

I'm not passing a context instruction for now, because the existing
approach of always using GEP1 for context could result in symmetry
issues.

Differential Revision: https://reviews.llvm.org/D93162