[clang] [AMDGPU] Programmatically port old `.def` clang builtins to `.td` (PR #175873)

[Shilei Tian via cfe-commits]

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@@ -200,7 +200,18 @@ class PrototypeParser {
       // we cannot have nested _ExtVector.
       if (Current.starts_with("_ExtVector<") ||
           Current.starts_with("_Vector<")) {
-        const size_t EndTemplate = Current.find('>', 0);
+        size_t Pos = Current.find('<');
+        int Depth = 1;
+
+        // There may be a nested address_space<...> modifier on the type.
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shiltian wrote:

Hmm, did I misunderstand it? There are plenty of tests under `clang/test/TableGen/`.

https://github.com/llvm/llvm-project/pull/175873