f97b29be88
Summary: The DAGCombiner is rewriting (canonicalizing) an ISD::ADD with no common bits set in the operands as an ISD::OR node. This could sometimes result in "missing out" on some combines that normally are performed for ADD. To be more specific this could happen if we already have rewritten an ADD into OR, and later (after legalizations or combines) we expose patterns that could have been optimized if we had seen the OR as an ADD (e.g. reassociations based on ADD). To make the DAG combiner less sensitive to if ADD or OR is used for these "no common bits set" ADD/OR operations we now apply most of the ADD combines also to an OR operation, when value tracking indicates that the operands have no common bits set. Reviewers: spatel, RKSimon, craig.topper, kparzysz Reviewed By: spatel Subscribers: arsenm, rampitec, lebedev.ri, jvesely, nhaehnle, hiraditya, javed.absar, llvm-commits Tags: #llvm Differential Revision: https://reviews.llvm.org/D59758 llvm-svn: 358965
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