[clang] [Clang] Improve concept performance 1/N (PR #188421)

[Younan Zhang via cfe-commits]

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@@ -1611,13 +1618,28 @@ namespace {
       }
       return Type;
     }
+
     // Override the default version to handle a rewrite-template-arg-pack case
     // for building a deduction guide.
     bool TransformTemplateArgument(const TemplateArgumentLoc &Input,
                                    TemplateArgumentLoc &Output,
                                    bool Uneval = false) {
       const TemplateArgument &Arg = Input.getArgument();
       std::vector<TemplateArgument> TArgs;
+      if (auto *Cache = SemaRef.CurrentCachedTemplateArgs;
+          TemplateArgsHashValue && Cache) {
+        llvm::FoldingSetNodeID ID = *TemplateArgsHashValue;
+        ID.AddInteger(SemaRef.ArgPackSubstIndex.toInternalRepresentation());
+        Input.getArgument().Profile(ID, SemaRef.Context);
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zyn0217 wrote:

No I don't. All is based on my analysis..

https://github.com/llvm/llvm-project/pull/188421