https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105524
Bug ID: 105524
Summary: -Wmaybe-uninitialized false-positive with switch of
enum with more than 2 elements
Product: gcc
Version: 12.1.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: nunoplopes at sapo dot pt
Target Milestone: ---
The following program gets a false-positive when compiled with `-Wall -O3
-fstrict-enums`:
// switch to 0 to make false-positive go away
#define DEF_C 1
enum foo { A, B
#if DEF_C
, C
#endif
};
void g(const char*);
void f(foo x) {
const char *str;
switch (x) {
case A: str = "a"; break;
case B: str = "b"; break;
#if DEF_C
case C: str = "c"; break;
#endif
}
g(str);
}
https://gcc.godbolt.org/z/h1rWqezY3
<source>: In function 'void f(foo)':
<source>:19:4: error: 'str' may be used uninitialized
[-Werror=maybe-uninitialized]
19 | g(str);
| ~^~~~~
<source>:11:15: note: 'str' was declared here
11 | const char *str;
| ^~~
cc1plus: all warnings being treated as errors
Compiler returned: 1
The error only repros with enums with more than 2 elements.
