[PATCH] D128919: [DAG] Teach isConstOrConstSplat about SPLAT_VECTORs

[Simon Pilgrim via Phabricator via llvm-commits]

RKSimon added a comment.

I've no objections, but the experts on SVE targets need to have final say.



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Comment at: llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp:10646
     // AllowTruncation is set.
     if (CN && (UndefElements.none() || AllowUndefs)) {
       EVT CVT = CN->getValueType(0);
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Please can you add a TODO - about whether we should allow UndefElements in non-DemandedElts?


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Comment at: llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp:10676
         BV->getConstantFPSplatNode(DemandedElts, &UndefElements);
     if (CN && (UndefElements.none() || AllowUndefs))
       return CN;
----------------
Please can you add a TODO - about whether we should allow UndefElements in non-DemandedElts?


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  https://reviews.llvm.org/D128919/new/

https://reviews.llvm.org/D128919