From mboxrd@z Thu Jan  1 00:00:00 1970
From: john@feith.com (John Wehle)
To: burley@gnu.org
Cc: law@cygnus.com, d.love@dl.ac.uk, egcs@cygnus.com, davem@dm.cobaltmicro.com
Subject: Re: ix86 double alignment (was Re: egcs-1.1 release schedule)
Date: Tue, 23 Jun 1998 03:32:00 -0000
Message-id: <199806230448.AAA10658@jwlab.FEITH.COM>
X-SW-Source: 1998-06/msg00780.html

> [...]
> The latter uses automatic arrays (which gcc and g77 support), it'd
> be great to get those 64-bit aligned as well.  The former is the
> most important thing we *aren't* aligning, currently, even with
> `-malign-double'.  (It should be aligned especially if `a' is an
> array, of course.)
> [...]
> Note that I suggested the gcc architecture (machine descriptions,
> etc.) be modified to include a more fine-grained expression of
> alignment requirements.  E.g. distinguishing hardware requirements
> (even instruction requirements, such as `ld' vs. `ldd' on SPARCv8)
> from ABI requirements from ideal performance settings.  But this
> suggestion was turned down at the time -- some seven years ago!

Though it's not as fine-grain as what's mentioned above it may be
worth while to consider using the DATA_ALIGNMENT macro when laying
out variables for the stack.  On the i386 it currently returns the
Intel recommended alignment for doubles, long doubles, arrays, etc.
(the recommended alignment for long doubles is different from doubles).

-- John
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