[PATCH] libstdc++: simd: allow x86 -mlong-double-64

[Alexandre Oliva]

On a target that defaults to -mlong-double-64 -msse,
standard_abi_usable.cc and other tests fail to compile because of the
assert that rejects long double.  As on ppc, we can trivially make
things work for -mlong-double-64.

Regstrapped on x86_64-linux-gnu.  Also tested with -mlong-double-64 on
libstdc++ tests that triggered the static_assert.  Ok to install?


for  libstdc++-v3/ChangeLog

	* include/experimental/bits/simd.h (__intrinsic_type): Accept
	64-bit long doubles on x86 SSE.
---
 libstdc++-v3/include/experimental/bits/simd.h |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/libstdc++-v3/include/experimental/bits/simd.h b/libstdc++-v3/include/experimental/bits/simd.h
index c2ac5adedaccf..b96818af6e6ff 100644
--- a/libstdc++-v3/include/experimental/bits/simd.h
+++ b/libstdc++-v3/include/experimental/bits/simd.h
@@ -2469,7 +2469,9 @@ template <>
 template <typename _Tp, size_t _Bytes>
   struct __intrinsic_type<_Tp, _Bytes, enable_if_t<__is_vectorizable_v<_Tp> && _Bytes <= 64>>
   {
-    static_assert(!is_same_v<_Tp, long double>,
+    // allow _Tp == long double with -mlong-double-64
+    static_assert(!(is_same_v<_Tp, long double>
+		    && sizeof(long double) > sizeof(double)),
 		  "no __intrinsic_type support for long double on x86");
 
     static constexpr size_t _S_VBytes = _Bytes <= 16 ? 16 : _Bytes <= 32 ? 32 : 64;


-- 
Alexandre Oliva, happy hacker            https://blog.lx.oliva.nom.br/
Free Software Activist     FSFLA co-founder     GNU Toolchain Engineer
More tolerance and less prejudice are key for inclusion and diversity.
Excluding neuro-others for not behaving ""normal"" is *not* inclusive!