https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109543
--- Comment #2 from avieira at gcc dot gnu.org ---
Sorry for the delay. Here's the typedefs with GNU vectors.
typedef struct
{
float __attribute__ ((vector_size(16))) v[2];
} STRUCT;
#ifdef GOOD
typedef STRUCT TYPE;
#else
typedef union
{
STRUCT s;
double d[2];
} TYPE;
#endif
To be fair I suspect you could see similar behaviour with just 16-byte vectors,
but with aarch64 the backend will know to use 64-bit scalar moves for 128-bit
BLKmodes, though even then, picking the vector mode would result in more
optimal (single vector move) code.
