[dragonegg PATCH] Use the preferred alignment when deciding whether to use an explicit alignment

[Peter Collingbourne]

On Tue, Apr 02, 2013 at 11:23:09PM +0200, Duncan Sands wrote:
> Hi Peter,
>
>> Use the preferred alignment when deciding whether to use an explicit
>> alignment.
>>
>> OK to commit?
>
> I don't like it.  An alignment of 0 for a global variable guarantess it gets
> at least the ABI alignment, but maybe no more.  The optimizers may increase it
> in cases where that seems safe and profitable to them, usually to the preferred
> alignment, but they may not always do so.  In such cases (where the global only
> gets the ABI alignment) your patch would decrease the alignment from what the
> user requested (the preferred alignment) to the ABI alignment, which would be
> wrong.

That makes sense.  What about this, where we always use an explicit
alignment if DECL_USER_ALIGN holds?

Thanks,
-- 
Peter
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