https://gcc.gnu.org/bugzilla/show_bug.cgi?id=118593
Bug ID: 118593
Summary: False-positive warning about applying bitwise
operation to a boolean expression
Product: gcc
Version: 14.2.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: kristoimenov at gmail dot com
Target Milestone: ---
The following code produces three warnings about applying ‘~’ on a boolean
expression. Clearly, the first bitwise NOT is applied to an unsigned integer;
the second is also applied to an unsigned integer, as ~ and type cast are
right-associative and with the same precedence; whereas the third bitwise NOT
is actually applied to a boolean expression. However, all three initialisers
produce the same warning.
```
int main()
{
unsigned s=42, r1=~((unsigned)(s==42)), r2=~(unsigned)(s==42), r3=~(s==42);
}
```
```
$ gcc -Wbool-operation a.c
a.c: In function ‘main’:
a.c:3:22: warning: ‘~’ on a boolean expression [-Wbool-operation]
3 | unsigned s=42, r=~(unsigned)(s==42);
| ^
a.c:3:22: note: did you mean to use logical not?
3 | unsigned s=42, r=~(unsigned)(s==42);
| ^
| !
```
