[PATCH] DAGCombiner: Assume invariant load cannot alias a store

[Matt Arsenault]

> Now that the store is known to not alias the load, GatherAllAliases decides that the best chain for the store at chain F is the CopyFromReg chain, putting it on the same chain as the load. This seems broken, but I don't think it will cause any actual problems.


This patch seems to solve the problem of moving the store’s chain to the CopyFromReg’s chain by not continuing the chain search unless the chained node is a MemSDNode. This seems only break 2 tests (PPC/ppc64-align-long-double.ll and SystemZ/spill-01.ll)

- F593783: 0001-Don-t-search-up-chain-through-non-memory-dependencie.patch <http://reviews.llvm.org/F593783>
- F593782: msg-12037-195.html <http://reviews.llvm.org/F593782>


http://reviews.llvm.org/D10749

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