[clang] [llvm] [CodeGen][LLVM] Make the `va_list` related intrinsics generic. (PR #85460)

[Matt Arsenault via llvm-commits]

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@@ -700,10 +700,13 @@ class MSBuiltin<string name> {
 //===--------------- Variable Argument Handling Intrinsics ----------------===//
 //
 
-def int_vastart : DefaultAttrsIntrinsic<[], [llvm_ptr_ty], [], "llvm.va_start">;
-def int_vacopy  : DefaultAttrsIntrinsic<[], [llvm_ptr_ty, llvm_ptr_ty], [],
-                            "llvm.va_copy">;
-def int_vaend   : DefaultAttrsIntrinsic<[], [llvm_ptr_ty], [], "llvm.va_end">;
+def int_vastart : DefaultAttrsIntrinsic<[],
+                                        [llvm_anyptr_ty], [], "llvm.va_start">;
+def int_vacopy  : DefaultAttrsIntrinsic<[],
+                                        [llvm_anyptr_ty, llvm_anyptr_ty], [],
+                                        "llvm.va_copy">;
----------------
arsenm wrote:

Would it make sense to emit these as p5.p0 pairs, such that we're assuming it's writing to the stack from an arbitrary pointer an optimize down to stack-to-stack copies? 

https://github.com/llvm/llvm-project/pull/85460