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

[Craig Topper via Phabricator via llvm-commits]

craig.topper added inline comments.


================
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),
----------------
RKSimon wrote:
> 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
Oh, right forgot we were in a nested loop.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D107068/new/

https://reviews.llvm.org/D107068