https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99768
Bug ID: 99768
Summary: [11 Regression] Bogus -Wuninitialized diagnostic with
type punning
Product: gcc
Version: 11.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: acoplan at gcc dot gnu.org
Target Milestone: ---
For the following code (which has a strict aliasing violation):
float foo(unsigned v)
{
unsigned tmp = v;
float *f = (float *)(&tmp);
return *f;
}
at -O2 -Wall we warn that tmp is used uninitialized:
test.c: In function ‘foo’:
test.c:5:12: warning: ‘tmp’ is used uninitialized [-Wuninitialized]
5 | return *f;
| ^~
test.c:3:14: note: ‘tmp’ declared here
3 | unsigned tmp = v;
| ^~~
but this is clearly bogus. Not sure if this is strictly considered a bug given
the strict aliasing problem, but thought it might be worth checking in any
case.
