https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110283
--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
As an aside, Eigen has some maybe wrong code in it:
```
# 55 "../../eigen-3.3.4/Eigen/src/Core/arch/SSE/PacketMath.h" 3 4
typedef __m128 Packet4f;
typedef __m128i Packet4i;
typedef __m128d Packet2d;
template<> struct is_arithmetic<__m128> { enum { value = true }; };
template<> struct is_arithmetic<__m128i> { enum { value = true }; };
template<> struct is_arithmetic<__m128d> { enum { value = true }; };
...
template<> struct unpacket_traits<Packet4f> { typedef float type; enum {size=4,
alignment=Aligned16}; typedef Packet4f half; };
template<> struct unpacket_traits<Packet2d> { typedef double type; enum
{size=2, alignment=Aligned16}; typedef Packet2d half; };
template<> struct unpacket_traits<Packet4i> { typedef int type; enum {size=4,
alignment=Aligned16}; typedef Packet4i half; };
```
Because __m128/__m128i/__m128d are all declared as may_alias but the template
will lose that attribute.
