From: Pavel Roskin <proski@gnu.org>
To: linux-sparse@vger.kernel.org
Subject: Bogus warning when comparing nocast short variables
Date: Wed, 21 Jul 2010 12:51:02 -0400 [thread overview]
Message-ID: <1279731062.9003.15.camel@mj> (raw)
Hello!
This test file causes a warning:
typedef short __attribute__((nocast)) u16;
int main(int argc, char **argv)
{
u16 i = (u16)argc;
u16 j = (u16)2;
return (i == j);
}
$ sparse test1.c
test1.c:6:17: warning: implicit cast from nocast type
test1.c:6:22: warning: implicit cast from nocast type
But this file doesn't cause any warning:
typedef short __attribute__((nocast)) u16;
int main(int argc, char **argv)
{
u16 i = (u16)argc;
u16 j = (u16)2;
switch (i) {
case j: return 1;;
default: return 0;;
}
}
I think the warnings are bogus. No cast should be needed to compare
variables of the same type.
The warning was actually found in the current Linux kernel, driver
zd1121rw. A fix was proposed, but I thing the fix belongs to the sparse
code.
--
Regards,
Pavel Roskin
next reply other threads:[~2010-07-21 16:51 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-07-21 16:51 Pavel Roskin [this message]
2010-07-22 22:35 ` Bogus warning when comparing nocast short variables Chris Li
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1279731062.9003.15.camel@mj \
--to=proski@gnu.org \
--cc=linux-sparse@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).