[all-commits] [llvm/llvm-project] 671333: [LoopVersioningLICM] Fix noalias metadata emission

[Nikita Popov via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: 6713332fddb796f5b14fcb6a7e5d36979676e4ab
      https://github.com/llvm/llvm-project/commit/6713332fddb796f5b14fcb6a7e5d36979676e4ab
  Author: Nikita Popov <nikita.ppv at gmail.com>
  Date:   2020-10-13 (Tue, 13 Oct 2020)

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

  Log Message:
  -----------
  [LoopVersioningLICM] Fix noalias metadata emission

The previous code added the scope on each iteration, so that the
same scope was represented many times in the same !noalias metadata.
That's legal, and semantically equivalent to only storing the scope
once, but it's also wasteful and may pessimize further optimization
if AATags get intersected naively, as done by the AliasSetTracker.