From: Matthias Kretz <m.kretz@gsi.de>
Date: Wed, 17 Apr 2024 08:35:47 +0000 (+0200)
Subject: libstdc++: Silence irrelevant warnings in <experimental/simd>
X-Git-Tag: releases/gcc-11.5.0~151
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=6679ea120ee06355ba309c53604b23909d325b98;p=thirdparty%2Fgcc.git

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 248237731268..56ec9dd4a84d 100644
--- 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 9703012a6d95..42e894ac3b0b 100644
--- 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);
   }