-malign-double

[kelley.r.cook@gm.com]

Jan could you please add this back into 3.1.1 too?  Technically, it is a
regression.

Kelley Cook





Jan Hubicka <jh@suse.cz> on 05/15/2002 04:37:20 AM

To:    Kelley Cook <kelley.r.cook@gm.com>
cc:    Jan Hubicka <jh@suse.cz>, gcc@gcc.gnu.org, David Ronis
       <ronis@ronispc.chem.mcgill.ca>, gcc-patches@gcc.gnu.org
Subject:    Re: -malign-double


> >Sorry to be a pest, but nobody answered this the last time I asked:
> >
> >I've just noticed that the 3.1 documentation for the -malign-double
> >flag no longer contain the warning about structures; i.e., it used to
> >read:
> >
> >
> >-malign-double'
> >`-mno-align-double'
> > Control whether GCC aligns `double', `long double', and `long
> > long' variables on a two word boundary or a one word boundary.
> > Aligning `double' variables on a two word boundary will produce
> > code that runs somewhat faster on a `Pentium' at the expense of
> > more memory.
> >
> > *Warning:* if you use the `-malign-double' switch, structures
> > containing the above types will be aligned differently than the
> > published application binary interface specifications for the 386.
> >
> >I'd been burned badly by not paying attention to this in the past.
> >
> >What is the current situation?
> >
> >David
>
> It disappeared during the checkin of this patch
>
>
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/Attic/invoke.texi.diff?r1=1.252&r2=1.253

>
> But the corresponding patch posted to gcc-patches
>
> http://gcc.gnu.org/ml/gcc-patches/2000-12/msg00719.html
>
> doesn't mention this.
I am installing the attached patch to the mainline as obvious.

Wed May 15 10:33:54 CEST 2002  Jan Hubicka  <jh@suse.cz>

 * invoke.texi (-malign-double): Re-add lost warning.

Index: doc/invoke.texi
===================================================================
RCS file: /cvs/gcc/egcs/gcc/doc/invoke.texi,v
retrieving revision 1.100
diff -c -3 -p -r1.100 invoke.texi
*** doc/invoke.texi     8 Jan 2002 19:59:50 -0000     1.100
--- doc/invoke.texi     15 May 2002 08:33:43 -0000
*************** boundary.  Aligning @code{double} variab
*** 7596,7601 ****
--- 7596,7605 ----
  produce code that runs somewhat faster on a @samp{Pentium} at the
  expense of more memory.

+ @strong{Warning:} if you use the @samp{-malign-double} switch,
+ structures containing the above types will be aligned differently than
+ the published application binary interface specifications for the 386.
+
  @item -m128bit-long-double
  @opindex m128bit-long-double
  Control the size of @code{long double} type. i386 application binary
  interface