[PATCH] D43425: [DSE] Don't DSE stores that subsequent memmove calls read from

[Sanjoy Das via Phabricator via llvm-commits]

sanjoy created this revision.
sanjoy added a reviewer: rsmith.
Herald added subscribers: jlebar, mcrosier.

We used to remove the first memmove in cases like this:

  memmove(p, p+2, 8);
  memmove(p, p+2, 8);

which is incorrect.  Fix this by changing isPossibleSelfRead to what was most
likely the intended behavior.

Historical note: the buggy code was added in https://reviews.llvm.org/rL120974
to address PR8728.


Repository:
  rL LLVM

https://reviews.llvm.org/D43425

Files:
  lib/Transforms/Scalar/DeadStoreElimination.cpp
  test/Transforms/DeadStoreElimination/simple.ll

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