[all-commits] [llvm/llvm-project] d605a1: [Intrinsics] Added writeonly attribute to the firs...

[Dávid Bolvanský via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: d605a119939a91477c0eb223d3a5d7d912825daa
      https://github.com/llvm/llvm-project/commit/d605a119939a91477c0eb223d3a5d7d912825daa
  Author: Dávid Bolvanský <david.bolvansky at gmail.com>
  Date:   2020-10-19 (Mon, 19 Oct 2020)

  Changed paths:
    M llvm/include/llvm/IR/Intrinsics.td
    M llvm/test/Bitcode/upgrade-memory-intrinsics.ll
    M llvm/test/Transforms/DeadStoreElimination/MSSA/memintrinsics.ll

  Log Message:
  -----------
  [Intrinsics] Added writeonly attribute to the first arg of llvm.memmove

D18714 introduced writeonly attribute:

"Also start using the attribute for memset, memcpy, and memmove intrinsics,
and remove their special-casing in BasicAliasAnalysis."

But actually, writeonly was not attached to memmove - oversight, it seems.

So let's add it. As we can see, this helps DSE to eliminate redundant stores.

Reviewed By: jdoerfert

Differential Revision: https://reviews.llvm.org/D89724