From: Alexandre Oliva <oliva@adacore.com>
Date: Mon, 23 Mar 2026 01:32:55 +0000 (-0300)
Subject: libstdc++: simd: allow x86 -mlong-double-64
X-Git-Tag: basepoints/gcc-17~490
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=35bd360eedefe761435a85a2867ff9859720e398;p=thirdparty%2Fgcc.git

libstdc++: simd: allow x86 -mlong-double-64

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.


for  libstdc++-v3/ChangeLog

	* include/experimental/bits/simd.h (__intrinsic_type): Accept
	64-bit long doubles on x86 SSE.
---

diff --git a/libstdc++-v3/include/experimental/bits/simd.h b/libstdc++-v3/include/experimental/bits/simd.h
index c2ac5adedac..b96818af6e6 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;