[PATCH] D58965: [DAGCombiner] Enable UADDO/USUBO vector combine support

Simon Pilgrim via Phabricator via llvm-commits llvm-commits at lists.llvm.org
Tue Mar 5 08:22:19 PST 2019


RKSimon marked an inline comment as done.
RKSimon added inline comments.


================
Comment at: lib/CodeGen/SelectionDAG/DAGCombiner.cpp:2463
   // If Y + 1 cannot overflow.
   if (N1.getOpcode() == ISD::ADDCARRY && isNullConstant(N1.getOperand(1))) {
     SDValue Y = N1.getOperand(0);
----------------
nikic wrote:
> Should this also become isNullorNullSplat? (Does ADDCARRY support vectors?)
AFAICT we don't have ISD::ADDCARRY/SUBCARRY support for vectors - it might be safest to just early-out from visitUADDOLike if VT.isVector()?


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  rL LLVM

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  https://reviews.llvm.org/D58965/new/

https://reviews.llvm.org/D58965





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