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[Bug c/35973] New: Incorrect warning: will never be executed
- From: "dot at dotat dot at" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 18 Apr 2008 16:05:31 -0000
- Subject: [Bug c/35973] New: Incorrect warning: will never be executed
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
This bug exists in various forms in multiple versions of gcc:
$ cat gccbug.c
struct sel {
const char *name;
unsigned int enabled;
};
int selog_on(struct sel *);
#define selog_on(sel) \
(sel.enabled == 0 \
? selog_on(&sel) \
: sel.enabled != 42)
void dostuff(int *);
void gccbug1(void) {
struct sel sel = { "test", 0 };
if(selog_on(sel)) {
dostuff(0);
}
}
void gccbug2(void) {
struct sel sel = { "test", 0 };
if(selog_on(sel)) {
int i;
dostuff(&i);
}
}
$ gcc -O -Wunreachable-code -c gccbug.c
gccbug.c: In function `gccbug2':
gccbug.c:25: warning: will never be executed
$ gcc --version
gcc --version
gcc (GCC) 3.4.4 [FreeBSD] 20050518
$ gcc -O -Wunreachable-code -c gccbug.c
gccbug.c: In function â??gccbug2â??:
gccbug.c:24: warning: will never be executed
gccbug.c: In function â??gccbug1â??:
gccbug.c:17: warning: will never be executed
$ gcc -O -Werror -Wunreachable-code -c gccbug.c
cc1: warnings being treated as errors
gccbug.c: In function â??gccbug2â??:
gccbug.c:24: warning: will never be executed
$ gcc --version
gcc (GCC) 4.1.2 20070115 (prerelease) (SUSE Linux)
$ gcc -O -Wunreachable-code -c gccbug.c
gccbug.c: In function 'gccbug2':
gccbug.c:24: warning: will never be executed
gccbug.c: In function 'gccbug1':
gccbug.c:17: warning: will never be executed
$ gcc -O -Werror -Wunreachable-code -c gccbug.c
cc1: warnings being treated as errors
gccbug.c: In function 'gccbug2':
gccbug.c:24: warning: will never be executed
$ gcc --version
gcc (GCC) 4.2.1 20070719 [FreeBSD]
--
Summary: Incorrect warning: will never be executed
Product: gcc
Version: 4.2.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: dot at dotat dot at
GCC host triplet: i386-undermydesk-freebsd
GCC target triplet: i386-undermydesk-freebsd
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35973