05.06.2015 13:02, Ondřej Bílka writes:
> Also as I mentioned bugs before gcc now doesn't handle alignment well so
> it doesn't optimize following to zero for aligned code.
>
> align = ((uintptr_t) x) % 16;
>
That is because GCC is conservative and supports some non-ABI-compliant
memory allocators which only guarantee 8-byte alignment, but
char *bar()
{
char *data = __builtin_malloc(64);
return data + ((unsigned long)data) % 8;
}
does get optimized to
bar:
.LFB1:
.cfi_startproc
movl $64, %edi
jmp malloc
.cfi_endproc
--
Regards,
Mikhail Maltsev
