https://gcc.gnu.org/bugzilla/show_bug.cgi?id=128465
Bug ID: 128465
Summary: Wrong -Wmaybe-uninitialized on an empty struct
Product: gcc
Version: 16.2.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: Laurent.Rineau__gcc at normalesup dot org
Target Milestone: ---
Created attachment 66090
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=66090&action=edit
test case
With the following code
```c++
struct Empty {};
struct S { char c; Empty empty; S() : c(0), empty() {} };
void g(const Empty&);
void f()
{
S s;
g(s.empty);
}
```
g++ version 16.2.1 (from Linux Fedora 45) triggers a -Wmaybe-uninitialized
warning with -O1:
```
$ g++ -Wmaybe-uninitialized -O1 -c go.cpp
go.cpp: In function ‘void f()’:
go.cpp:7:4: warning: ‘s’ may be used uninitialized [-Wmaybe-uninitialized]
7 | g(s.empty);
| ~^~~~~~~~~
go.cpp:3:6: note: by argument 1 of type ‘const Empty&’ to ‘void g(const
Empty&)’ declared here
3 | void g(const Empty&);
| ^
go.cpp:6:5: note: ‘s’ declared here
6 | S s;
| ^
```
I think it should not, because:
- the member `s.empty` was initialized
- that member is an empty struct anyway.
