https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102508
Bug ID: 102508
Summary: ICE on coroutine when awaiting inside a statement
expression (in transform_local_var_uses, at
cp/coroutines.cc:2102)
Product: gcc
Version: 11.2.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: delleyves at gmx dot ch
Target Milestone: ---
Created attachment 51513
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=51513&action=edit
Preprocessed source.
The following code ICEs with a segmentation fault (release-checking) / assert
(all-checking):
```
#include <coroutine>
#include <stdexcept>
#include <outcome-experimental.hpp>
namespace outcome = OUTCOME_V2_NAMESPACE;
template <typename T>
using result = outcome::experimental::status_result<T>;
template <typename result_type>
struct CoroAwaiter {
template <typename LazyAsync>
explicit CoroAwaiter(LazyAsync &&lazy_async) {
(void)std::forward<LazyAsync>(lazy_async)();
}
bool await_ready() noexcept;
void await_suspend(std::coroutine_handle<> awaiting_coroutine) noexcept;
result_type &&await_resume() noexcept;
};
template <typename R>
struct CoroBase {
using result_type = R;
struct promise_type {
template <typename LazyAsync>
auto await_transform(
LazyAsync &&lazy_async) {
using nested_result_type = typename std::invoke_result_t<LazyAsync
&&>::result_type;
return
CoroAwaiter<nested_result_type>(std::forward<LazyAsync>(lazy_async));
}
#ifdef __cpp_exceptions
void unhandled_exception() noexcept;
#endif
template <typename V>
void return_value(V &&value) noexcept;
std::suspend_never initial_suspend() noexcept;
std::suspend_always final_suspend() noexcept;
static CoroBase get_return_object_on_allocation_failure() noexcept;
CoroBase get_return_object() noexcept;
};
CoroBase() = default;
CoroBase(CoroBase &&) = default;
CoroBase(const CoroBase &) = delete;
};
template <typename T>
using Coro = CoroBase<result<T>>;
[[nodiscard]] Coro<bool> bar() noexcept;
[[nodiscard]] Coro<void> foo() noexcept {
#if true
bool ok = OUTCOME_CO_TRYX(co_await [&]() { return bar(); });
#else
auto res = co_await [&]() { return bar(); };
if(!res.has_value()) {
co_return outcome::failure(std::move(res).error());
}
bool ok = res.value();
#endif
(void)ok;
co_return outcome::success();
}
```
Replace the `#if true` with `#if false` and the code compiles fine - despite
the two branches roughly having the same effect, though `OUTCOME_CO_TRYX`
utilises a Statement Expression (GCC / Clang extension).
Unfortunately, I haven't been able to reproduce the ICE without involving the
outcome library.
This issue seems to exist since as long as coroutines are available in GCC. In
particular, the code provided above ICEs on godbolt.org with a segfault on all
GCC 10.1 through 11.2 as well as (trunk) and (coroutines), when compiled with
"--std=c++20 -fcoroutines" and the outcome library enabled. The preprocessed
sources are from a local, checking GCC build of current master (11.2.1), where
instead of segfaulting it ICEs in an assert at `in transform_local_var_uses, at
cp/coroutines.cc:2102`.
The full compilation output is:
```
Using built-in specs.
COLLECT_GCC=/Users/yves/SDKs/gcc-11-20210926/bin/g++-11-20210926
Target: x86_64-apple-darwin20.6.0
Configured with: /var/tmp/yves/gcc-11-20210926_source/configure
--prefix=/Users/yves/SDKs/gcc-11-20210926 --enable-bootstrap
--enable-checking=yes --enable-languages=c,c++,lto
--with-default-libstdcxx-abi=new --enable-libstdcxx-debug --enable-plugin
--disable-multilib
--with-sysroot=/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk
--with-pkgversion=yves-Yves-MBookPro15 --program-suffix=-11-20210926
Thread model: posix
Supported LTO compression algorithms: zlib
gcc version 11.2.1 20210926 (yves-Yves-MBookPro15)
COLLECT_GCC_OPTIONS='-v' '-save-temps' '-D' 'EMBCPP_OUTCOME_SINGLE_HEADER' '-D'
'OUTCOME_DISABLE_EXECINFO' '-I'
'/Users/yves/epymetrics/core-fw/compiler-crash-evaluation/../deps/outcome/single-header'
'-Wall' '-Wextra' '-fno-rtti' '-fno-exceptions' '-O0' '-g3' '-fcoroutines'
'-std=c++20' '-o' 'test.o' '-c' '-mmacosx-version-min=11.5.0'
'-asm_macosx_version_min=11.5' '-shared-libgcc' '-mtune=core2'
/Users/yves/SDKs/gcc-11-20210926/libexec/gcc/x86_64-apple-darwin20.6.0/11.2.1/cc1plus
-E -quiet -v -I
/Users/yves/epymetrics/core-fw/compiler-crash-evaluation/../deps/outcome/single-header
-dD -D__DYNAMIC__ -D EMBCPP_OUTCOME_SINGLE_HEADER -D OUTCOME_DISABLE_EXECINFO
/Users/yves/epymetrics/core-fw/compiler-crash-evaluation/test-case.cpp -fPIC
-mmacosx-version-min=11.5.0 -mtune=core2 -std=c++20 -Wall -Wextra -fno-rtti
-fno-exceptions -fcoroutines -g3 -fworking-directory -O0 -fpch-preprocess -o
test.ii
ignoring nonexistent directory
"/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/usr/local/include"
ignoring nonexistent directory
"/Users/yves/SDKs/gcc-11-20210926/lib/gcc/x86_64-apple-darwin20.6.0/11.2.1/../../../../x86_64-apple-darwin20.6.0/include"
ignoring nonexistent directory
"/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/Library/Frameworks"
#include "..." search starts here:
#include <...> search starts here:
/Users/yves/epymetrics/core-fw/compiler-crash-evaluation/../deps/outcome/single-header
/Users/yves/SDKs/gcc-11-20210926/lib/gcc/x86_64-apple-darwin20.6.0/11.2.1/../../../../include/c++/11.2.1
/Users/yves/SDKs/gcc-11-20210926/lib/gcc/x86_64-apple-darwin20.6.0/11.2.1/../../../../include/c++/11.2.1/x86_64-apple-darwin20.6.0
/Users/yves/SDKs/gcc-11-20210926/lib/gcc/x86_64-apple-darwin20.6.0/11.2.1/../../../../include/c++/11.2.1/backward
/Users/yves/SDKs/gcc-11-20210926/lib/gcc/x86_64-apple-darwin20.6.0/11.2.1/include
/Users/yves/SDKs/gcc-11-20210926/lib/gcc/x86_64-apple-darwin20.6.0/11.2.1/include-fixed
/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/usr/include
/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/System/Library/Frameworks
End of search list.
COLLECT_GCC_OPTIONS='-v' '-save-temps' '-D' 'EMBCPP_OUTCOME_SINGLE_HEADER' '-D'
'OUTCOME_DISABLE_EXECINFO' '-I'
'/Users/yves/epymetrics/core-fw/compiler-crash-evaluation/../deps/outcome/single-header'
'-Wall' '-Wextra' '-fno-rtti' '-fno-exceptions' '-O0' '-g3' '-fcoroutines'
'-std=c++20' '-o' 'test.o' '-c' '-mmacosx-version-min=11.5.0'
'-asm_macosx_version_min=11.5' '-shared-libgcc' '-mtune=core2'
/Users/yves/SDKs/gcc-11-20210926/libexec/gcc/x86_64-apple-darwin20.6.0/11.2.1/cc1plus
-fpreprocessed test.ii -fPIC -quiet -dumpbase test.cpp -dumpbase-ext .cpp
-mmacosx-version-min=11.5.0 -mtune=core2 -g3 -O0 -Wall -Wextra -std=c++20
-version -fno-rtti -fno-exceptions -fcoroutines -o test.s
GNU C++20 (yves-Yves-MBookPro15) version 11.2.1 20210926
(x86_64-apple-darwin20.6.0)
compiled by GNU C version 11.2.1 20210926, GMP version 6.1.0, MPFR
version 3.1.6, MPC version 1.0.3, isl version isl-0.18-GMP
GGC heuristics: --param ggc-min-expand=30 --param ggc-min-heapsize=4096
GNU C++20 (yves-Yves-MBookPro15) version 11.2.1 20210926
(x86_64-apple-darwin20.6.0)
compiled by GNU C version 11.2.1 20210926, GMP version 6.1.0, MPFR
version 3.1.6, MPC version 1.0.3, isl version isl-0.18-GMP
GGC heuristics: --param ggc-min-expand=30 --param ggc-min-heapsize=4096
Compiler executable checksum: cd23c6af9953d6c303dd89c0d734e2b7
/Users/yves/epymetrics/core-fw/compiler-crash-evaluation/test-case.cpp: In
function ‘Coro<void> foo()’:
/Users/yves/epymetrics/core-fw/compiler-crash-evaluation/test-case.cpp:72:1:
internal compiler error: in transform_local_var_uses, at cp/coroutines.cc:2102
72 | }
| ^
Please submit a full bug report,
with preprocessed source if appropriate.
See <https://gcc.gnu.org/bugs/> for instructions.
```
