On Thu, Apr 14, 2011 at 8:26 AM, Michael Matz <[email protected]> wrote:
> Hi,
>
> On Thu, 14 Apr 2011, Richard Guenther wrote:
>
>> > + if (align > DECL_ALIGN (decl))
>> > + DECL_ALIGN (decl) = align;
>>
>> Shouldn't this unconditionally set DECL_ALIGN in case
>> LOCAL_DECL_ALINGMENT returns something smaller?
>
> Decreasing alignment of DECLs points to a problem elsewhere, so perhaps an
> assert that this doesn't happen is better. Decreasing is a problem
> because it's not conservative: there might have been code generated
> already assuming the once larger alignment that then possibly breaks if it
> turns out the alignment is actually smaller.
ia32 may decrease local variable alignment:
/* Don't do dynamic stack realignment for long long objects with
-mpreferred-stack-boundary=2. */
if (!TARGET_64BIT
&& align == 64
&& ix86_preferred_stack_boundary < 64
&& (mode == DImode || (type && TYPE_MODE (type) == DImode))
&& (!type || !TYPE_USER_ALIGN (type))
&& (!decl || !DECL_USER_ALIGN (decl)))
align = 32;
I am running bootstrap/test on Linux/x86-64 and Linux/ia32.
--
H.J.
