[llvm] [IR] Add llvm `clmul` intrinsic (PR #140301)

[Matt Arsenault via llvm-commits]

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@@ -3907,6 +3907,10 @@ bool SelectionDAGLegalize::ExpandNode(SDNode *Node) {
     if (SDValue Expanded = TLI.expandFunnelShift(Node, DAG))
       Results.push_back(Expanded);
     break;
+  case ISD::CLMUL:
+    if (SDValue Expanded = TLI.expandCLMUL(Node, DAG))
+      Results.push_back(Expanded);
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arsenm wrote:

This should be a never-fail return 

https://github.com/llvm/llvm-project/pull/140301