https://gcc.gnu.org/bugzilla/show_bug.cgi?id=118194
Bug ID: 118194
Summary: spurious warning with -Wmaybe-uninitialized
Product: gcc
Version: 14.2.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: sshannin at gmail dot com
Target Milestone: ---
There are a number of other open bug reports about this warning, but none of
them seemed quite the same. This is different in that:
- doesn't rely on C++ constructs such as lambdas
- occurs at all optimization levels -O0 through -O3
- very simple path with no control flow
#include <stdlib.h>
#include <sys/mman.h>
void *foo(int sz) {
void *p = malloc(sz);
mlock(p, sz);
return p;
}
The above minimal example triggers a maybe-uninitialized warning:
<source>: In function 'foo':
<source>:6:5: warning: 'p' may be used uninitialized [-Wmaybe-uninitialized]
6 | mlock(p, sz);
| ^~~~~~~~~~~~
In file included from <source>:2:
/usr/include/x86_64-linux-gnu/sys/mman.h:103:12: note: by argument 1 of type
'const void *' to 'mlock' declared here
103 | extern int mlock (const void *__addr, size_t __len) __THROW;
| ^~~~~
It looks like this was introduced starting in 11.1 and is present up through
trunk.
