[PATCH] D107068: [DAG] DAGCombiner::visitVECTOR_SHUFFLE - recognise INSERT_SUBVECTOR patterns.

[Simon Pilgrim via Phabricator via llvm-commits]

RKSimon added inline comments.


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Comment at: llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp:21342
+          if (0 <= RHSStartIdx && i == (NumSubElts - 1))
+            return DAG.getNode(ISD::INSERT_SUBVECTOR, SDLoc(N), VT, LHS,
+                               RHS.getOperand(RHSStartIdx / NumSubElts),
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craig.topper wrote:
> Why can't this be after the loop and all of the breaks replaced with return SDValue()?
Because we have an outer loop at the top trying all possible positions for SubIdx


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https://reviews.llvm.org/D107068