http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56726
H.J. Lu <hjl.tools at gmail dot com> changed:
What |Removed |Added
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CC| |hjl.tools at gmail dot com
--- Comment #1 from H.J. Lu <hjl.tools at gmail dot com> 2013-03-25 20:04:44
UTC ---
(In reply to comment #0)
> Observed malloc alignment for the i386 ABI is double POINTER_SIZE.
> BITS_PER_WORD, the current default, is usually too small. (It's right only on
> X32.)
>
> Proposed patch:
>
> --- gcc/config/i386/i386.h (revision 197055)
> +++ gcc/config/i386/i386.h (working copy)
> @@ -815,6 +815,14 @@
> x86_field_alignment (FIELD, COMPUTED)
> #endif
>
> +/* The maximum alignment 'malloc' honors.
> +
> + This value is taken from glibc documentation for memalign(). It may
> + be up to double the very conservative GCC default. This should be safe,
> + since even the GCC 4.8 default of BIGGEST_ALIGNMENT usually worked. */
> +
> +#define MALLOC_ABI_ALIGNMENT (POINTER_SIZE * 2)
> +
This isn't correct for x32, whose pointer size is 4 bytes with malloc
aligned to 16 bytes.
