[llvm] [GlobalISel] Add `GITypeOf` special type (PR #66079)

[Matt Arsenault via llvm-commits]

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@@ -92,6 +92,14 @@ bool GIMatchTableExecutor::executeMatchTable(
     return true;
   };
 
+  // If the index is >= 0, it's an index in the type objects generated by
+  // TableGen. If the index is <0, it's an index in the recorded types object.
+  auto getTypeFromIdx = [&](int64_t Idx) -> const LLT & {
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arsenm wrote:

return LLT by value 

https://github.com/llvm/llvm-project/pull/66079