From: Eric Botcazou <ebotcazou@adacore.com>
To: Richard Guenther <richard.guenther@gmail.com>
Cc: Michael Matz <matz@suse.de>, gcc@gcc.gnu.org
Subject: Re: Do BLKmode bit-fields still exist?
Date: Fri, 06 Nov 2009 11:29:00 -0000 [thread overview]
Message-ID: <200911061228.38766.ebotcazou@adacore.com> (raw)
In-Reply-To: <84fc9c000911060153m4fbd86efqaa823c71d15543b6@mail.gmail.com>
> Isn't it enough to specify DECL_PACKED here? The tree.h docs
> about DECL_BIT_FIELD are a bit unspecific compared to
> DECL_PACKED.
>
> /* Nonzero in a FIELD_DECL means it is a bit field, and must be
> accessed specially. */
>
> vs.
>
> /* In a FIELD_DECL, indicates this field should be bit-packed. */
>
> where it seems, as your field isn't a bitfield, using DECL_PACKED
> looks more appropriate?
No, DECL_PACKED is an "input" flag for stor-layout.c, it isn't used in the
middle-end (except in the recently added contains_packed_reference but this
is wrong and should be fixed), the "output" flag that drives the middle-end
is DECL_BIT_FIELD. stor-layout.c attempts to clear the latter to improve the
code, it never changes the former.
--
Eric Botcazou
next prev parent reply other threads:[~2009-11-06 11:29 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-11-05 17:03 Michael Matz
2009-11-05 17:42 ` Jeff Law
2009-11-06 9:47 ` Eric Botcazou
2009-11-06 9:54 ` Richard Guenther
2009-11-06 11:29 ` Eric Botcazou [this message]
2009-11-06 16:24 ` Michael Matz
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