[PATCH] [x86] Add a ZERO_EXTEND_VECTOR_INREG DAG node and use it when widening vector types to be legal and a ZERO_EXTEND node is encountered.

[Benjamin Kramer]

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Comment at: lib/CodeGen/SelectionDAG/LegalizeVectorOps.cpp:750
@@ +749,3 @@
+  return DAG.getNode(ISD::BITCAST, DL, VT,
+                     DAG.getVectorShuffle(SrcVT, DL, Zero, Src, ShuffleMask));
+}
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Can we get away with creating illegal shuffles here or should we ask the backend if the mask is legal first?

http://reviews.llvm.org/D4405