https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111728
Bug ID: 111728
Summary: C++ 20 coroutine segmentation fault in generic lambda
Product: gcc
Version: 13.2.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: yunus at ayar dot eu
Target Milestone: ---
Created attachment 56074
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=56074&action=edit
Compressed version of main.cpp.ii (~ 5.5 MB) from g++ -save-temps
The following code causes a segmentation fault with ASIO 1.28, C++ 20's
coroutines and evaluating of expressions inside a generic coroutine lambda. I
tried to strip the test case as much as possible:
```cpp
#include <asio.hpp>
#include <cstddef>
inline asio::awaitable<std::size_t> write_fields()
{
std::byte static_buffer[10];
co_await [&](auto field) -> asio::awaitable<int> {
// Next line is not ok.
if (0 == sizeof(static_buffer));
co_return 0;
}(0);
co_return 0;
}
int main() { static_cast<void>(write_fields()); }
```
My exact version:
```txt
Using built-in specs.
COLLECT_GCC=g++
COLLECT_LTO_WRAPPER=/usr/libexec/gcc/x86_64-redhat-linux/13/lto-wrapper
OFFLOAD_TARGET_NAMES=nvptx-none
OFFLOAD_TARGET_DEFAULT=1
Target: x86_64-redhat-linux
Configured with: ../configure --enable-bootstrap
--enable-languages=c,c++,fortran,objc,obj-c++,ada,go,d,m2,lto --prefix=/usr
--mandir=/usr/share/man --infodir=/usr/share/info
--with-bugurl=http://bugzilla.redhat.com/bugzilla --enable-shared
--enable-threads=posix --enable-checking=release --enable-multilib
--with-system-zlib --enable-__cxa_atexit --disable-libunwind-exceptions
--enable-gnu-unique-object --enable-linker-build-id
--with-gcc-major-version-only --enable-libstdcxx-backtrace
--with-libstdcxx-zoneinfo=/usr/share/zoneinfo --with-linker-hash-style=gnu
--enable-plugin --enable-initfini-array
--with-isl=/builddir/build/BUILD/gcc-13.2.1-20230728/obj-x86_64-redhat-linux/isl-install
--enable-offload-targets=nvptx-none --without-cuda-driver
--enable-offload-defaulted --enable-gnu-indirect-function --enable-cet
--with-tune=generic --with-arch_32=i686 --build=x86_64-redhat-linux
--with-build-config=bootstrap-lto --enable-link-serialization=1
Thread model: posix
Supported LTO compression algorithms: zlib zstd
gcc version 13.2.1 20230728 (Red Hat 13.2.1-1) (GCC)
```
I compiled the attached (main.cpp.ii) with: g++ main.cpp.ii -std=gnu++20
The following output was generated:
```txt
/home/yunus/Projects/terraqtt/examples/main.cpp: In instantiation of
‘write_fields(write_fields()::_Z12write_fieldsv.Frame*)::<lambda(auto:50)>
[with auto:50 = int]’:
/home/yunus/Projects/terraqtt/examples/main.cpp:12:4: required from here
/home/yunus/Projects/terraqtt/examples/main.cpp:12:3: internal compiler error:
Segmentation fault
12 | }(0);
| ^
Please submit a full bug report, with preprocessed source.
See <http://bugzilla.redhat.com/bugzilla> for instructions.
Preprocessed source stored into /tmp/cchUnOPu.out file, please attach this to
your bugreport.
```
