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From: Michael Marks <Michael.Marks@internetmachines.com>
To: nobody@gcc.gnu.org
Cc: gcc-prs@gcc.gnu.org,
Subject: RE: c/10226: unsigned short promotion with bitwise inversion
Date: Wed, 26 Mar 2003 22:06:00 -0000 [thread overview]
Message-ID: <20030326215601.15620.qmail@sources.redhat.com> (raw)
The following reply was made to PR c/10226; it has been noted by GNATS.
From: Michael Marks <Michael.Marks@internetmachines.com>
To: 'Glen Nakamura' <glen@imodulo.com>, Falk Hueffner
<falk.hueffner@student.uni-tuebingen.de>
Cc: Michael Marks <Michael.Marks@internetmachines.com>,
gcc-gnats@gcc.gnu.org
Subject: RE: c/10226: unsigned short promotion with bitwise inversion
Date: Wed, 26 Mar 2003 13:50:29 -0800
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Either is far clearer than the original.
I like the second one better.
Just one other comment, are both promoted, and are both unsigned after the
promotion.
I thought they are promoted to int. As per you earlier...
The ~ operator is subject to integer promotion,
so with the implicit conversions the expression becomes:
if ((int) B == ~((int) A))
which is indeed false in the example above.
But like I said earlier, either message below is far clearer.
Thanks,
Michael.
-----Original Message-----
From: Glen Nakamura [mailto:glen@imodulo.com]
Sent: Wednesday, March 26, 2003 1:49 PM
To: Falk Hueffner
Cc: Michael Marks; gcc-gnats@gcc.gnu.org
Subject: Re: c/10226: unsigned short promotion with bitwise inversion
On Wed, Mar 26, 2003 at 10:39:43PM +0100, Falk Hueffner wrote:
> Indeed. Currently, it says:
> warning: comparison of promoted ~unsigned with unsigned
> Suggestion:
> warning: comparison of ~(promoted unsigned) with unsigned
How about one of these:
warning: comparison of promoted ~unsigned with unsigned is always false
warning: comparison of ~(promoted unsigned) with unsigned is always false
- glen
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<P><FONT SIZE=2>Either is far clearer than the original. </FONT>
<BR><FONT SIZE=2>I like the second one better.</FONT>
</P>
<P><FONT SIZE=2>Just one other comment, are both promoted, and are both unsigned after the promotion.</FONT>
<BR><FONT SIZE=2>I thought they are promoted to int. As per you earlier...</FONT>
</P>
<P><FONT SIZE=2>The ~ operator is subject to integer promotion,</FONT>
<BR><FONT SIZE=2>so with the implicit conversions the expression becomes:</FONT>
<BR><FONT SIZE=2> if ((int) B == ~((int) A))</FONT>
<BR><FONT SIZE=2>which is indeed false in the example above.</FONT>
</P>
<P><FONT SIZE=2>But like I said earlier, either message below is far clearer.</FONT>
</P>
<P><FONT SIZE=2>Thanks,</FONT>
<BR><FONT SIZE=2>Michael.</FONT>
</P>
<P><FONT SIZE=2>-----Original Message-----</FONT>
<BR><FONT SIZE=2>From: Glen Nakamura [<A HREF="mailto:glen@imodulo.com">mailto:glen@imodulo.com</A>]</FONT>
<BR><FONT SIZE=2>Sent: Wednesday, March 26, 2003 1:49 PM</FONT>
<BR><FONT SIZE=2>To: Falk Hueffner</FONT>
<BR><FONT SIZE=2>Cc: Michael Marks; gcc-gnats@gcc.gnu.org</FONT>
<BR><FONT SIZE=2>Subject: Re: c/10226: unsigned short promotion with bitwise inversion</FONT>
</P>
<BR>
<P><FONT SIZE=2>On Wed, Mar 26, 2003 at 10:39:43PM +0100, Falk Hueffner wrote:</FONT>
<BR><FONT SIZE=2>> Indeed. Currently, it says:</FONT>
<BR><FONT SIZE=2>> warning: comparison of promoted ~unsigned with unsigned</FONT>
<BR><FONT SIZE=2>> Suggestion:</FONT>
<BR><FONT SIZE=2>> warning: comparison of ~(promoted unsigned) with unsigned</FONT>
</P>
<P><FONT SIZE=2>How about one of these:</FONT>
<BR><FONT SIZE=2>warning: comparison of promoted ~unsigned with unsigned is always false</FONT>
<BR><FONT SIZE=2>warning: comparison of ~(promoted unsigned) with unsigned is always false</FONT>
</P>
<P><FONT SIZE=2>- glen</FONT>
</P>
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next reply other threads:[~2003-03-26 21:56 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-03-26 22:06 Michael Marks [this message]
-- strict thread matches above, loose matches on Subject: below --
2003-03-27 0:16 Michael Marks
2003-03-26 23:06 Falk Hueffner
2003-03-26 22:36 Glen Nakamura
2003-03-26 22:26 Glen Nakamura
2003-03-26 22:26 Falk Hueffner
2003-03-26 21:56 Glen Nakamura
2003-03-26 21:56 Falk Hueffner
2003-03-26 21:16 ebotcazou
2003-03-26 21:16 Michael Marks
2003-03-26 20:36 Glen Nakamura
2003-03-26 19:56 Michael Marks
2003-03-26 18:26 Falk Hueffner
2003-03-26 18:16 mmarks
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