libstdc++: Update value of __cpp_lib_constexpr_char_traits for C++20

Although not required by SD-6 or the C++20 draft, we define the macro
__cpp_lib_constexpr_char_traits to indicate support for P0432R1. This
updates the value in C++20 mode for the P1032R1 changes to char_traits.

	* include/bits/char_traits.h (__cpp_lib_constexpr_char_traits):
	Update value for C++20.
	* include/std/version (__cpp_lib_constexpr_char_traits): Likewise.
	* testsuite/21_strings/char_traits/requirements/constexpr_functions_c++17.cc:
	Update expected value.
	* testsuite/21_strings/char_traits/requirements/constexpr_functions_c++20.cc:
	Likewise.

diff --git a/libstdc++-v3/include/bits/char_traits.h b/libstdc++-v3/include/bits/char_traits.h
index c623a6713f62d43c56b54c277e421594de604a3c..84c2d1b7ff2fedda0fe22a8746833bb0af0a07ae 100644 (file)
--- a/libstdc++-v3/include/bits/char_traits.h
+++ b/libstdc++-v3/include/bits/char_traits.h
@@ -236,7 +236,14 @@ namespace std _GLIBCXX_VISIBILITY(default)
 _GLIBCXX_BEGIN_NAMESPACE_VERSION
 
 #if __cplusplus >= 201703L
-#define __cpp_lib_constexpr_char_traits 201611
+
+#if __cplusplus == 201703L
+// Unofficial macro indicating P0426R1 support
+# define __cpp_lib_constexpr_char_traits 201611L
+#else
+// Also support P1032R1 in C++20
+# define __cpp_lib_constexpr_char_traits 201811L
+#endif
 
   /**
    *  @brief Determine whether the characters of a NULL-terminated

diff --git a/libstdc++-v3/include/std/version b/libstdc++-v3/include/std/version
index c6bde2cfbda756257621f2a07b1afb66ee9484da..f64aff4f52016b1394c783da818a7eb114de426b 100644 (file)
--- a/libstdc++-v3/include/std/version
+++ b/libstdc++-v3/include/std/version
@@ -127,7 +127,7 @@
 #define __cpp_lib_boyer_moore_searcher 201603
 #define __cpp_lib_chrono 201611
 #define __cpp_lib_clamp 201603
-#define __cpp_lib_constexpr_char_traits 201611
+#define __cpp_lib_constexpr_char_traits 201611L
 #define __cpp_lib_enable_shared_from_this 201603
 #define __cpp_lib_execution 201902L // FIXME: should be 201603L
 #define __cpp_lib_filesystem 201703
@@ -192,16 +192,18 @@
 
 #if _GLIBCXX_HOSTED
 #undef __cpp_lib_array_constexpr
+#undef __cpp_lib_constexpr_char_traits
 #define __cpp_lib_array_constexpr 201811L
 #define __cpp_lib_assume_aligned 201811L
 #define __cpp_lib_bind_front 201907L
 // FIXME: #define __cpp_lib_execution 201902L
 #define __cpp_lib_integer_comparison_functions 202002L
 #define __cpp_lib_constexpr_algorithms 201806L
+#define __cpp_lib_constexpr_char_traits 201811L
 #define __cpp_lib_constexpr_complex 201711L
 #define __cpp_lib_constexpr_dynamic_alloc 201907L
 #define __cpp_lib_constexpr_functional 201907L
-# define __cpp_lib_constexpr_iterator 201811L
+#define __cpp_lib_constexpr_iterator 201811L
 #define __cpp_lib_constexpr_memory 201811L
 #define __cpp_lib_constexpr_numeric 201911L
 #define __cpp_lib_constexpr_string_view 201811L

diff --git a/libstdc++-v3/testsuite/21_strings/char_traits/requirements/constexpr_functions_c++17.cc b/libstdc++-v3/testsuite/21_strings/char_traits/requirements/constexpr_functions_c++17.cc
index 7cb950b89f5e4918835fd262c0369b519119da7d..55dcba48db65475ee6b7f81dbb948085d0c261c3 100644 (file)
--- a/libstdc++-v3/testsuite/21_strings/char_traits/requirements/constexpr_functions_c++17.cc
+++ b/libstdc++-v3/testsuite/21_strings/char_traits/requirements/constexpr_functions_c++17.cc
@@ -75,8 +75,10 @@ template<typename CT>
 
 #ifndef __cpp_lib_constexpr_char_traits
 # error Feature-test macro for constexpr char_traits is missing
-#elif __cpp_lib_constexpr_char_traits != 201611
+#elif __cpp_lib_constexpr_char_traits < 201611
 # error Feature-test macro for constexpr char_traits has the wrong value
+#elif __cpp_lib_constexpr_char_traits > 201611 && __cplusplus == 201703
+# error Feature-test macro for constexpr char_traits has wrong value for C++17
 #endif
 
 static_assert( test_assign<std::char_traits<char>>() );

diff --git a/libstdc++-v3/testsuite/21_strings/char_traits/requirements/constexpr_functions_c++20.cc b/libstdc++-v3/testsuite/21_strings/char_traits/requirements/constexpr_functions_c++20.cc
index 6358640c1cb7a0f573b79f487c66c527e2bad6c2..63c7c9cbb575f9217578ede19fb50ed819350d92 100644 (file)
--- a/libstdc++-v3/testsuite/21_strings/char_traits/requirements/constexpr_functions_c++20.cc
+++ b/libstdc++-v3/testsuite/21_strings/char_traits/requirements/constexpr_functions_c++20.cc
@@ -32,7 +32,7 @@ template<typename CT>
 
 #ifndef __cpp_lib_constexpr_char_traits
 # error Feature-test macro for constexpr char_traits is missing
-#elif __cpp_lib_constexpr_char_traits != 201611
+#elif __cpp_lib_constexpr_char_traits != 201811
 # error Feature-test macro for constexpr char_traits has the wrong value
 #endif