https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91423
Bug ID: 91423
Summary: address-of-packed-member when taking packed struct
member by value
Product: gcc
Version: 9.1.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: anders at knatten dot org
Target Milestone: ---
Compiling this with `-std=c++17 -Wall` on gcc 9.1.0:
```
#include <array>
struct __attribute__((__packed__)) Vec : std::array<std::size_t, 2>
{};
struct __attribute__((__packed__)) S
{
Vec size;
};
void g()
{
S s{};
Vec size = s.size;
}
```
gives:
```
<source>:14:18: warning: taking address of packed member of 'S' may result in
an unaligned pointer value [-Waddress-of-packed-member]
14 | Vec size = s.size;
```
However, I'm not taking the address of the packed member, I'm taking it by
value. I think gcc shouldn't warn in this case.
Godbolt: https://godbolt.org/z/v4GZ6f
