[libcxx-commits] [libcxx] [libc++] Simplify the implementation of conditional a bit (PR #199916)

[via libcxx-commits]

llvmorg-github-actions[bot] wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-libcxx

Author: Nikolas Klauser (philnik777)

<details>
<summary>Changes</summary>

We can use our internal `_If` instead of specializing `conditional` for selecting the appropriate type.


---
Full diff: https://github.com/llvm/llvm-project/pull/199916.diff


1 Files Affected:

- (modified) libcxx/include/__type_traits/conditional.h (+2-12) 


``````````diff
diff --git a/libcxx/include/__type_traits/conditional.h b/libcxx/include/__type_traits/conditional.h
index 71882fb1917b1..0daa7737bed06 100644
--- a/libcxx/include/__type_traits/conditional.h
+++ b/libcxx/include/__type_traits/conditional.h
@@ -35,20 +35,10 @@ struct _IfImpl<false> {
 template <bool _Cond, class _IfRes, class _ElseRes>
 using _If _LIBCPP_NODEBUG = typename _IfImpl<_Cond>::template _Select<_IfRes, _ElseRes>;
 
-template <bool _Bp, class _If, class _Then>
+template <bool _Bp, class _IfRes, class _ElseRes>
 struct _LIBCPP_NO_SPECIALIZATIONS conditional {
-  using type _LIBCPP_NODEBUG = _If;
-};
-
-_LIBCPP_DIAGNOSTIC_PUSH
-#if __has_warning("-Winvalid-specialization")
-_LIBCPP_CLANG_DIAGNOSTIC_IGNORED("-Winvalid-specialization")
-#endif
-template <class _If, class _Then>
-struct conditional<false, _If, _Then> {
-  using type _LIBCPP_NODEBUG = _Then;
+  using type _LIBCPP_NODEBUG = _If<_Bp, _IfRes, _ElseRes>;
 };
-_LIBCPP_DIAGNOSTIC_POP
 
 #if _LIBCPP_STD_VER >= 14
 template <bool _Bp, class _IfRes, class _ElseRes>

``````````

</details>


https://github.com/llvm/llvm-project/pull/199916