[llvm] [DXIL] Model DXIL Class and Shader Model association of DXIL Ops in DXIL.td (PR #87803)

[S. Bharadwaj Yadavalli via llvm-commits]

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@@ -172,9 +176,34 @@ DXILOperationDesc::DXILOperationDesc(const Record *R) {
   if (!OverloadParamIndices.empty()) {
     if (OverloadParamIndices.size() > 1)
       report_fatal_error("Multiple overload type specification not supported",
-                         false);
+                         /*gen_crash_diag*/ false);
     OverloadParamIndex = OverloadParamIndices[0];
   }
+
+  // Get valid overload types of the Operation
+  std::vector<Record *> OverloadTypeRecs =
+      R->getValueAsListOfDefs("OpOverloadTypes");
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bharadwajy wrote:

> Usually better to use `SmallVector` rather than a `std::vector` on the stack, especially for something that we wouldn't expect very many elements in.

Type of `OverloadTypeRecs` is declared to be same as the return type of `Record::getValueAsListOfDefs(StringRef FieldName)` viz., `std::vector<Record*> `. 

https://github.com/llvm/llvm-project/pull/87803