[llvm] TableGen: Replace assertion with error for unexpected pattern inputs (PR #159687)

[Sergei Barannikov via llvm-commits]

================
@@ -2795,7 +2795,11 @@ bool TreePatternNode::ApplyTypeConstraints(TreePattern &TP, bool NotRegisters) {
     return MadeChange;
   }
 
-  assert(getOperator()->isSubClassOf("SDNodeXForm") && "Unknown node type!");
+  if (!getOperator()->isSubClassOf("SDNodeXForm")) {
+    TP.error("unknown node type '" + getOperator()->getName() +
+             " in input pattern");
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s-barannikov wrote:

```suggestion
             "' in input pattern");
```

https://github.com/llvm/llvm-project/pull/159687