[clang] [CIR] Record the source level identity of functions on cir.func (PR #207261)

[Erich Keane via cfe-commits]

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@@ -4025,6 +4025,7 @@ def CIR_FuncOp : CIR_Op<"func", [
     CIR_OptionalPriorityAttr:$global_ctor_priority,
     CIR_OptionalPriorityAttr:$global_dtor_priority,
     OptionalAttr<CIR_CXXSpecialMemberAttr>:$cxx_special_member,
+    OptionalAttr<CIR_FuncInfoAttr>:$func_info,
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erichkeane wrote:

Oh, huh, I think that is probably a good idea.  I wonder if we should have this info BE a `CXXSpecialMemberAttr` and generalize that name (Special member is a term of art in C++, but something that means similar).

https://github.com/llvm/llvm-project/pull/207261