[clang] Emit constrained atan2 intrinsic for clang builtin (PR #113636)

[Farzon Lotfi via cfe-commits]

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@@ -13,7 +13,7 @@ using size_t = unsigned long;
 #endif // SPIR
 } // namespace std
 
-float __builtin_atan2f(float, float);
+float __builtin_erff(float);
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farzonl wrote:

Just want to put a note here we are doing this because atan2 would no longer test the calling convention intended.

https://github.com/llvm/llvm-project/pull/113636