[PATCH] D51737: DAG: Combine extract_vector_elt of concat_vectors

Simon Pilgrim via Phabricator via llvm-commits llvm-commits at lists.llvm.org
Wed Sep 12 03:53:55 PDT 2018


RKSimon added inline comments.


================
Comment at: lib/CodeGen/SelectionDAG/DAGCombiner.cpp:15493
+    } else if (InVec.getOpcode() == ISD::CONCAT_VECTORS &&
+               !BCNumEltsChanged) {
+      // extract_vector_elt (concat_vectors v2i16:a, v2i16:b), 0
----------------
Do we need a TLI.isOperationLegal(ISD::EXTRACT_VECTOR_ELT, ConcatVT) check?


https://reviews.llvm.org/D51737





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