[llvm] [TableGen] Add support for emitting new function definition to return a range of results for Primary Key (PR #96174)

[Garvit Gupta via llvm-commits]

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@@ -135,6 +138,12 @@ class SearchIndex {
   //
   // Can only be used when the first field is an integral (non-string) type.
   bit EarlyOut = false;
+
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quic-garvgupt wrote:

The primarykey field in genericTable is an instance of `SearchIndex` and is parsed using `parseSearchIndex` which is also used for parsing non-primary functions. Therefore it is necessary to keep `ReturnRange` in `SearchIndex` even though it will always throw an error.

https://github.com/llvm/llvm-project/pull/96174