https://gcc.gnu.org/bugzilla/show_bug.cgi?id=117475
Bug ID: 117475
Summary: C++20: Union object with atomic integer cannot be
statically initialized
Product: gcc
Version: 13.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: sebastian.hu...@embedded-brains.de
Target Milestone: ---
The following test program fails to compile with GCC and -std=c++20:
#include <atomic>
typedef std::atomic_int Atomic_Int;
struct S {
Atomic_Int v;
};
union U {
S s;
};
U obj;
For example:
aarch64-rtems6-gcc -Wall -Wextra -std=c++20 -pedantic -S test.cc
test.cc:13:3: error: use of deleted function 'U::U()'
13 | U obj;
| ^~~
test.cc:9:7: note: 'U::U()' is implicitly deleted because the default
definition would be ill-formed:
9 | union U {
| ^
test.cc:10:5: error: union member 'U::s' with non-trivial 'constexpr S::S()'
10 | S s;
| ^
It works with clang 17.0.6:
clang -Wall -Wextra -std=c++20 -pedantic -S test.cc -o -
.text
.file "test.cc"
.type obj,@object # @obj
.bss
.globl obj
.p2align 2, 0x0
obj:
.zero 4
.size obj, 4
.section ".linker-options","e",@llvm_linker_options
.ident "clang version 17.0.6"
.section ".note.GNU-stack","",@progbits
.addrsig
