[all-commits] [llvm/llvm-project] 2431b1: [DSE, MemorySSA] Limit elimination at end of functi...

[Florian Hahn via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: 2431b143aeacda1c92b82fbae3f7121d78048785
      https://github.com/llvm/llvm-project/commit/2431b143aeacda1c92b82fbae3f7121d78048785
  Author: Florian Hahn <flo at fhahn.com>
  Date:   2020-08-24 (Mon, 24 Aug 2020)

  Changed paths:
    M llvm/lib/Transforms/Scalar/DeadStoreElimination.cpp
    M llvm/test/Transforms/DeadStoreElimination/MSSA/simple.ll

  Log Message:
  -----------
  [DSE,MemorySSA] Limit elimination at end of function to single UO.

Limit elimination of stores at the end of a function to MemoryDefs with
a single underlying object, to save compile time.

In practice, the case with multiple underlying objects seems not very
important in practice. For -O3 -flto on MultiSource/SPEC2000/SPEC2006
this results in a total of 2 more stores being eliminated.

We can always re-visit that in the future.