[llvm] [SelectionDAG] Expand CTTZ_ELTS[_ZERO_POISON] and handle legalization (PR #188691)

[David Sherwood via llvm-commits]

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@@ -2993,8 +2995,8 @@ SDValue DAGTypeLegalizer::PromoteIntOp_VECTOR_HISTOGRAM(SDNode *N,
   return SDValue(DAG.UpdateNodeOperands(N, NewOps), 0);
 }
 
-SDValue DAGTypeLegalizer::PromoteIntOp_VECTOR_FIND_LAST_ACTIVE(SDNode *N,
-                                                               unsigned OpNo) {
+SDValue DAGTypeLegalizer::PromoteIntOp_VECTOR_FIND_LAST_ACTIVE_CTTZ_ELTS(
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david-arm wrote:

I wonder if it's worth renaming this to something like `PromoteIntOp_UnaryMaskOp` or `PromoteIntOp_UnaryBooleanVectorOp`? I can believe that other opcodes may eventually end up in here too.

https://github.com/llvm/llvm-project/pull/188691