[PATCH v23 33/33] libstdc++: Optimize std::is_invocable compilation performance

[Ken Matsui]

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

libstdc++-v3/ChangeLog:

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

Signed-off-by: Ken Matsui <kmat...@gcc.gnu.org>
---
 libstdc++-v3/include/std/type_traits                        | 6 ++++++
 .../testsuite/20_util/is_invocable/incomplete_args_neg.cc   | 1 +
 .../testsuite/20_util/is_invocable/incomplete_neg.cc        | 1 +
 3 files changed, 8 insertions(+)

diff --git a/libstdc++-v3/include/std/type_traits 
b/libstdc++-v3/include/std/type_traits
index 75a94cb8d7e..91851b78c7e 100644
--- a/libstdc++-v3/include/std/type_traits
+++ b/libstdc++-v3/include/std/type_traits
@@ -3167,9 +3167,15 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     using invoke_result_t = typename invoke_result<_Fn, _Args...>::type;
 
   /// std::is_invocable
+#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_invocable)
+  template<typename _Fn, typename... _ArgTypes>
+    struct is_invocable
+    : public __bool_constant<__is_invocable(_Fn, _ArgTypes...)>
+#else
   template<typename _Fn, typename... _ArgTypes>
     struct is_invocable
     : __is_invocable_impl<__invoke_result<_Fn, _ArgTypes...>, void>::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_invocable/incomplete_args_neg.cc 
b/libstdc++-v3/testsuite/20_util/is_invocable/incomplete_args_neg.cc
index 34d1d9431d1..6db004bdc43 100644
--- a/libstdc++-v3/testsuite/20_util/is_invocable/incomplete_args_neg.cc
+++ b/libstdc++-v3/testsuite/20_util/is_invocable/incomplete_args_neg.cc
@@ -18,6 +18,7 @@
 // <http://www.gnu.org/licenses/>.
 
 // { dg-error "must be a complete class" "" { target *-*-* } 0 }
+// { dg-error "incomplete type" "" { target *-*-* } 0 }
 
 #include <type_traits>
 
diff --git a/libstdc++-v3/testsuite/20_util/is_invocable/incomplete_neg.cc 
b/libstdc++-v3/testsuite/20_util/is_invocable/incomplete_neg.cc
index e1e54d25ee5..608218b533c 100644
--- a/libstdc++-v3/testsuite/20_util/is_invocable/incomplete_neg.cc
+++ b/libstdc++-v3/testsuite/20_util/is_invocable/incomplete_neg.cc
@@ -18,6 +18,7 @@
 // <http://www.gnu.org/licenses/>.
 
 // { dg-error "must be a complete class" "" { target *-*-* } 0 }
+// { dg-error "incomplete type" "" { target *-*-* } 0 }
 
 #include <type_traits>
 
-- 
2.42.0