fix: bind swizzle shuffle mask to constexpr for gcc-15

g++-15 rejects a constexpr helper call passed inline to _mm_permute_ps/
_mm_permute_pd ('the last argument must be an 8-bit immediate'). Bind the
mod_shuffle result to a constexpr local first, matching the convention used
at every other call site in the codebase.

Author: DiamonDinoia

include/xsimd/arch/xsimd_avx_128.hpp

@@ -210,13 +210,15 @@ namespace xsimd
         template <class A, uint32_t V0, uint32_t V1, uint32_t V2, uint32_t V3>
         XSIMD_INLINE batch<float, A> swizzle(batch<float, A> const& self, batch_constant<uint32_t, A, V0, V1, V2, V3>, requires_arch<avx_128>) noexcept
         {
-            return _mm_permute_ps(self, detail::mod_shuffle(V0, V1, V2, V3));
+            constexpr auto mask = detail::mod_shuffle(V0, V1, V2, V3);
+            return _mm_permute_ps(self, mask);
         }
 
         template <class A, uint32_t V0, uint32_t V1>
         XSIMD_INLINE batch<double, A> swizzle(batch<double, A> const& self, batch_constant<uint64_t, A, V0, V1>, requires_arch<avx_128>) noexcept
         {
-            return _mm_permute_pd(self, detail::mod_shuffle(V0, V1));
+            constexpr auto mask = detail::mod_shuffle(V0, V1);
+            return _mm_permute_pd(self, mask);
         }
 
     }