libstdc++: Make <experimental/simd> depend on C++17

Signed-off-by: Jonathan Wakely <jwakely@redhat.com>
libstdc++-v3/ChangeLog:

	* include/experimental/simd: Do not define anything pre-C++17.

(cherry picked from commit 36adced3b6b7cae17d7b42e4573bd0f4194b1f70)

diff --git a/libstdc++-v3/include/experimental/simd b/libstdc++-v3/include/experimental/simd
index da2d0479cf3bb2050249ccbc7e10e612dcda6dc7..beccbc14fa54820395329a9a977601c16351ed5f 100644 (file)
--- a/libstdc++-v3/include/experimental/simd
+++ b/libstdc++-v3/include/experimental/simd
@@ -33,6 +33,8 @@
 #ifndef _GLIBCXX_EXPERIMENTAL_SIMD
 #define _GLIBCXX_EXPERIMENTAL_SIMD
 
+#if __cplusplus >= 201703L
+
 #define __cpp_lib_experimental_parallel_simd 201803
 
 #pragma GCC diagnostic push
@@ -66,5 +68,6 @@
 
 #pragma GCC diagnostic pop
 
+#endif // C++17
 #endif // _GLIBCXX_EXPERIMENTAL_SIMD
 // vim: ft=cpp