https://gcc.gnu.org/bugzilla/show_bug.cgi?id=43798
Alexander Monakov <amonakov at gcc dot gnu.org> changed:
What |Removed |Added
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CC| |amonakov at gcc dot gnu.org
--- Comment #15 from Alexander Monakov <amonakov at gcc dot gnu.org> ---
Not 100% sure if it's known, the comments don't seem to mention this, so I'll
note for completeness sake:
placement of the attribute makes a difference, here it looks like the attribute
on the type introduced via a typedef leads to weird semantics, while the
attribute on the struct itself leads to logical 32/16 size/align:
typedef struct __attribute__((aligned(16))) {
unsigned long long w[3];
} UINT192;
int a1 = __alignof(UINT192);
int s1 = sizeof(UINT192);
a1:
.long 16
s1:
.long 32
Also one cannot create a 64-bit aligned/128-bit sized typedef to 'long double'
on 32-bit:
typedef long double T __attribute__((aligned(8)));
int a1 = __alignof(T);
int s1 = sizeof(T);
a1:
.long 8
s1:
.long 12
