[PATCH] D17279: [Sink] Don't move calls to readonly functions across stores

[Nicolai Hähnle via llvm-commits]

nhaehnle updated this revision to Diff 55294.
nhaehnle added a comment.

Update and change to deal with argmemonly.

This required a subtle change to getModRefInfo(Instruction, ImmutableCallSite)
to ensure that the semantics are equal to that of getModRefInfo(CS1, CS2) when
the Instruction is a call-site.

I would consider the old behavior to be a bug, which seems to not have surfaced
because it seems the only user of that particular getModRefInfo overload is in
MemorySSA, and that user only checks the return value for != MR_NoModRef.

While the relation is non-commutative, changing the order of the call-sites
may change the result from MR_Ref to MR_Mod and vice versa, but never to
MR_NoModRef.


http://reviews.llvm.org/D17279

Files:
  lib/Analysis/AliasAnalysis.cpp
  lib/Transforms/Scalar/Sink.cpp
  test/Transforms/Sink/call.ll

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