http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59223
Bug ID: 59223
Summary: -Wmaybe-uninitialized and -Wuninitialized
relationships
Product: gcc
Version: 4.9.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: middle-end
Assignee: unassigned at gcc dot gnu.org
Reporter: vincent-gcc at vinc17 dot net
With:
* gcc-4.8 (Debian 4.8.2-5) 4.8.2
* gcc (Debian 20131021-1) 4.9.0 20131021 (experimental) [trunk revision 203899]
It seems that -Wmaybe-uninitialized works only if -Wuninitialized is enabled.
Moreover -Wmaybe-uninitialized is enabled by -Wuninitialized. I wonder whether
this is intended or something is missing in the man page (the gcc 4.8.2 one
doesn't say anything about these relationships).
xvii:~> cat tst2.c
int foo (int x)
{
int y;
if (x == 0)
y = 1;
else if (x == 1)
y = 2;
return y;
}
First test:
xvii:~> gcc-snapshot -O2 -Wmaybe-uninitialized -c tst2.c
No warning here; -Wuninitialized is needed to trigger the
[-Wmaybe-uninitialized] warning (see below).
Second test:
xvii:~> gcc-snapshot -O2 -Wuninitialized -c tst2.c
tst2.c: In function 'foo':
tst2.c:8:3: warning: 'y' may be used uninitialized in this function
[-Wmaybe-uninitialized]
return y;
^
The use of -Wuninitialized alone has enabled -Wmaybe-uninitialized.
