[PATCH v14 26/26] libstdc++: Optimize std::is_nothrow_invocable compilation performance

[Ken Matsui]

This patch optimizes the compilation performance of
std::is_nothrow_invocable by dispatching to the new
__is_nothrow_invocable built-in trait.

libstdc++-v3/ChangeLog:

        * include/std/type_traits (is_nothrow_invocable): Use
        __is_nothrow_invocable built-in trait.
        * testsuite/20_util/is_nothrow_invocable/incomplete_args_neg.cc:
        Handle the new error from __is_nothrow_invocable.
        * testsuite/20_util/is_nothrow_invocable/incomplete_neg.cc:
        Likewise.

Signed-off-by: Ken Matsui <kmat...@gcc.gnu.org>
---
 libstdc++-v3/include/std/type_traits                          | 4 ++++
 .../20_util/is_nothrow_invocable/incomplete_args_neg.cc       | 1 +
 .../testsuite/20_util/is_nothrow_invocable/incomplete_neg.cc  | 1 +
 3 files changed, 6 insertions(+)

diff --git a/libstdc++-v3/include/std/type_traits 
b/libstdc++-v3/include/std/type_traits
index 9af233bcc75..093d85a51a8 100644
--- a/libstdc++-v3/include/std/type_traits
+++ b/libstdc++-v3/include/std/type_traits
@@ -3265,8 +3265,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
   /// std::is_nothrow_invocable
   template<typename _Fn, typename... _ArgTypes>
     struct is_nothrow_invocable
+#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_nothrow_invocable)
+    : public __bool_constant<__is_nothrow_invocable(_Fn, _ArgTypes...)>
+#else
     : __and_<__is_invocable_impl<__invoke_result<_Fn, _ArgTypes...>, void>,
             __call_is_nothrow_<_Fn, _ArgTypes...>>::type
+#endif
     {
       static_assert(std::__is_complete_or_unbounded(__type_identity<_Fn>{}),
        "_Fn must be a complete class or an unbounded array");
diff --git 
a/libstdc++-v3/testsuite/20_util/is_nothrow_invocable/incomplete_args_neg.cc 
b/libstdc++-v3/testsuite/20_util/is_nothrow_invocable/incomplete_args_neg.cc
index 3c225883eaf..3f8542dd366 100644
--- a/libstdc++-v3/testsuite/20_util/is_nothrow_invocable/incomplete_args_neg.cc
+++ b/libstdc++-v3/testsuite/20_util/is_nothrow_invocable/incomplete_args_neg.cc
@@ -18,6 +18,7 @@
 // <http://www.gnu.org/licenses/>.
 
 // { dg-error "must be a complete class" "" { target *-*-* } 0 }
+// { dg-prune-output "invalid use of incomplete type" }
 
 #include <type_traits>
 
diff --git 
a/libstdc++-v3/testsuite/20_util/is_nothrow_invocable/incomplete_neg.cc 
b/libstdc++-v3/testsuite/20_util/is_nothrow_invocable/incomplete_neg.cc
index 5a728bfa03b..d3bdf08448b 100644
--- a/libstdc++-v3/testsuite/20_util/is_nothrow_invocable/incomplete_neg.cc
+++ b/libstdc++-v3/testsuite/20_util/is_nothrow_invocable/incomplete_neg.cc
@@ -18,6 +18,7 @@
 // <http://www.gnu.org/licenses/>.
 
 // { dg-error "must be a complete class" "" { target *-*-* } 0 }
+// { dg-prune-output "invalid use of incomplete type" }
 
 #include <type_traits>
 
-- 
2.44.0