[PATCH] D36774: DAG: Allow creating extract_vector_elt post-legalize

[Simon Pilgrim via Phabricator via llvm-commits]

RKSimon added inline comments.


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Comment at: lib/CodeGen/SelectionDAG/DAGCombiner.cpp:13886
+        TLI.isOperationLegal(ISD::EXTRACT_VECTOR_ELT, VT) ||
+        TLI.isOperationExpand(ISD::VECTOR_SHUFFLE, VT)) {
       EVT IndexTy = TLI.getVectorIdxTy(DAG.getDataLayout());
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I wonder if it'd be safe to test for TLI.isOperationLegalOrCustom(ISD::EXTRACT_VECTOR_ELT, VT) if the extract is from the same vector type and the same index (constant or variable) as the original? Would that cover the cases you have?


https://reviews.llvm.org/D36774