[src/trunk]: src/sys/netinet6 Some fun in trying to work out what was broken ...

[abs <abs%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/42c0df25fe8a
branches:  trunk
changeset: 779891:42c0df25fe8a
user:      abs <abs%NetBSD.org@localhost>
date:      Mon Jun 25 17:25:29 2012 +0000

description:
Some fun in trying to work out what was broken with gcc-4.1 to
trigger the following warning when gcc-4.5 was silent:
  nd6_rtr.c: In function 'nd6_ra_input':
  nd6_rtr.c:788: warning: 'ext' may be used uninitialized in this function
Eventually determined that it was not unreasonable for gcc-4.1 to
bleat in this case as there is a nasty 'goto insert' which could
indeed have resulted in an uninitialised variable use. Yay gcc 4.1.

diffstat:

 sys/netinet6/nd6_rtr.c |  6 +++---
 1 files changed, 3 insertions(+), 3 deletions(-)

diffs (34 lines):

diff -r efd5637fa72e -r 42c0df25fe8a sys/netinet6/nd6_rtr.c
--- a/sys/netinet6/nd6_rtr.c    Mon Jun 25 16:48:55 2012 +0000
+++ b/sys/netinet6/nd6_rtr.c    Mon Jun 25 17:25:29 2012 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: nd6_rtr.c,v 1.83 2012/06/23 03:14:04 christos Exp $    */
+/*     $NetBSD: nd6_rtr.c,v 1.84 2012/06/25 17:25:29 abs Exp $ */
 /*     $KAME: nd6_rtr.c,v 1.95 2001/02/07 08:09:47 itojun Exp $        */
 
 /*
@@ -31,7 +31,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: nd6_rtr.c,v 1.83 2012/06/23 03:14:04 christos Exp $");
+__KERNEL_RCSID(0, "$NetBSD: nd6_rtr.c,v 1.84 2012/06/25 17:25:29 abs Exp $");
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -744,6 +744,7 @@
 defrtrlist_update(struct nd_defrouter *new)
 {
        struct nd_defrouter *dr, *n;
+       struct in6_ifextra *ext = new->ifp->if_afdata[AF_INET6];
        int s = splsoftnet();
 
        if ((dr = defrouter_lookup(&new->rtaddr, new->ifp)) != NULL) {
@@ -785,7 +786,6 @@
                return (dr);
        }
 
-       struct in6_ifextra *ext = new->ifp->if_afdata[AF_INET6];
        if (ip6_maxifdefrouters >= 0 &&
            ext->ndefrouters >= ip6_maxifdefrouters) {
                splx(s);