[llvm] [DAGCombine] Count leading ones: refine post DAG/Type Legalisation if promotion (PR #102877)

[Min-Yih Hsu via llvm-commits]

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@@ -464,7 +467,7 @@ struct TernaryOpc_match {
   bool match(const MatchContext &Ctx, SDValue N) {
     if (sd_context_match(N, Ctx, m_Opc(Opcode))) {
       EffectiveOperands<ExcludeChain> EO(N);
-      assert(EO.Size == 3);
+      assert(EO.Size == 3U + 2 * N->isVPOpcode());
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mshockwave wrote:

would it be better if we put this into `EffectiveOperands`? `EffectiveOperands` was invented to abstract away "don't care" operands, like input chain, under certain circumstances so I feel like it fits well with what you're doing here.

https://github.com/llvm/llvm-project/pull/102877