libstdc++: Silence irrelevant warnings in <experimental/simd>

Avoid
-Wnarrowing in C code;
-Wtautological-compare in unconditional static_assert (necessary for
faking a dependency on a template parameter)

Signed-off-by: Matthias Kretz <m.kretz@gsi.de>
libstdc++-v3/ChangeLog:

	* include/experimental/bits/simd.h: Ignore -Wnarrowing for
	arm_neon.h.
	(__int_for_sizeof): Replace tautological compare with checking
	for invalid template parameter value.
	* include/experimental/bits/simd_builtin.h (__extract_part):
	Remove tautological compare by combining two static_assert.

(cherry picked from commit e7a3ad29c9c832b6ae999cbfb0af89e121959030)

diff --git a/libstdc++-v3/include/experimental/bits/simd.h b/libstdc++-v3/include/experimental/bits/simd.h
index 2482377312685dfe32233bb26b7313033dc5bbd6..56ec9dd4a84d230c9f42598e4c1d09c8168cf2d6 100644 (file)
--- a/libstdc++-v3/include/experimental/bits/simd.h
+++ b/libstdc++-v3/include/experimental/bits/simd.h
@@ -42,7 +42,12 @@
 #if _GLIBCXX_SIMD_X86INTRIN
 #include <x86intrin.h>
 #elif _GLIBCXX_SIMD_HAVE_NEON
+#pragma GCC diagnostic push
+// narrowing conversion of '__a' from 'uint64_t' {aka 'long long unsigned int'} to
+//   'int64x1_t' {aka 'long long int'} [-Wnarrowing]
+#pragma GCC diagnostic ignored "-Wnarrowing"
 #include <arm_neon.h>
+#pragma GCC diagnostic pop
 #endif
 
 /** @ingroup ts_simd
@@ -385,6 +390,7 @@ template <size_t _Bytes>
   constexpr auto
   __int_for_sizeof()
   {
+    static_assert(_Bytes > 0);
     if constexpr (_Bytes == sizeof(int))
       return int();
   #ifdef __clang__
@@ -450,7 +456,7 @@ template <size_t _Bytes>
        return _Ip{};
       }
     else
-      static_assert(_Bytes != _Bytes, "this should be unreachable");
+      static_assert(_Bytes == 0, "this should be unreachable");
   }
 #pragma GCC diagnostic pop
 

diff --git a/libstdc++-v3/include/experimental/bits/simd_builtin.h b/libstdc++-v3/include/experimental/bits/simd_builtin.h
index 9703012a6d952dce2cefaf1b83510cfdfb0aaf42..42e894ac3b0bf20474d63a83e5fceff24266b61a 100644 (file)
--- a/libstdc++-v3/include/experimental/bits/simd_builtin.h
+++ b/libstdc++-v3/include/experimental/bits/simd_builtin.h
@@ -276,8 +276,7 @@ template <int _Index, int _Total, int _Combine = 1, size_t _Np>
   __extract_part(const _SimdWrapper<bool, _Np> __x)
   {
     static_assert(_Combine == 1, "_Combine != 1 not implemented");
-    static_assert(__have_avx512f && _Np == _Np);
-    static_assert(_Total >= 2 && _Index + _Combine <= _Total && _Index >= 0);
+    static_assert(__have_avx512f && _Total >= 2 && _Index + _Combine <= _Total && _Index >= 0);
     return __x._M_data >> (_Index * _Np / _Total);
   }