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path: root/test/CodeGen/PowerPC/merge-st-chain-op.ll
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2015-09-28[DAGCombine] Fix getStoreMergeAndAliasCandidates's AA-enabled chain walkingHal Finkel
When AA is being used, non-aliasing stores are canonicalized to use the same chain, and DAGCombiner::getStoreMergeAndAliasCandidates can take advantage of this by looking only as users of a store's chain operand. However, user iteration is not result-number specific, we need to check that the use is as a chain operand, and not via some other operand. It is certainly possible to have another potentially-aliasing store, which shares the first's base pointer, and uses the first's chain's node via some other operand. Failure to catch this situation caused, at least in the included test case, an assert later because the relative sequence-number ordering caused later replacement to create a cycle in the DAG. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@248698 91177308-0d34-0410-b5e6-96231b3b80d8