[Bug middle-end/115859] New: ICE: in lower_stmt, at gimple-low.cc:724 with -g and __attribute__((optimize(3)))

[iamanonymous.cs at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115859

            Bug ID: 115859
           Summary: ICE: in lower_stmt, at gimple-low.cc:724 with -g and
                    __attribute__((optimize(3)))
           Product: gcc
           Version: 15.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: middle-end
          Assignee: unassigned at gcc dot gnu.org
          Reporter: iamanonymous.cs at gmail dot com
  Target Milestone: ---

*******************************************************************************
OS and Platform:
$ uname -a:
Linux 65dac7c84719 4.15.0-213-generic #224-Ubuntu SMP Mon Jun 19 13:30:12 UTC
2023 x86_64 x86_64 x86_64 GNU/Linux
*******************************************************************************
gcc version:
Using built-in specs.
COLLECT_GCC=/home/software/gcc-trunk-3aa004f/bin/gcc
COLLECT_LTO_WRAPPER=/home/software/gcc-trunk-3aa004f/libexec/gcc/x86_64-pc-linux-gnu/15.0.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: ../gcc/configure --disable-multilib --disable-bootstrap
--enable-languages=c,c++ --prefix=/home/software/gcc-trunk-3aa004f
--enable-coverage
Thread model: posix
Supported LTO compression algorithms: zlib
gcc version 15.0.0 20240630 (experimental) (GCC) 

*******************************************************************************
Program:
$ cat mutant.C
namespace std {
template <typename a, typename> struct coroutine_traits {
  using promise_type = a : promise_type;
} template <typename = void> struct coroutine_handle;
struct coroutine_handle<> {
} template <typename> struct coroutine_handle {
} class b {
  get_return_object()
} class c {
  using promise_type = b;
};
__attribute__((optimize(3))) auto d(int awaitable) -> c {
  co_await awaitable

*******************************************************************************
Command Lines:
$ gcc -g -std=c++20 mutant.C
mutant.C:3:26: error: found ':' in nested-name-specifier, expected '::'
    3 |   using promise_type = a : promise_type;
      |                          ^
      |                          ::
mutant.C:4:2: error: expected ';' after struct definition
    4 | } template <typename = void> struct coroutine_handle;
      |  ^
      |  ;
mutant.C:5:1: error: an explicit specialization must be preceded by 'template
<>'
    5 | struct coroutine_handle<> {
      | ^~~~~~~~~~~~~~~~~~~~~~~~~
      | template <> 
mutant.C:6:2: error: expected ';' after struct definition
    6 | } template <typename> struct coroutine_handle {
      |  ^
      |  ;
mutant.C:7:2: error: expected ';' after struct definition
    7 | } class b {
      |  ^
      |  ;
mutant.C:8:3: error: ISO C++ forbids declaration of 'get_return_object' with no
type [-fpermissive]
    8 |   get_return_object()
      |   ^~~~~~~~~~~~~~~~~
mutant.C:8:21: error: expected ';' at end of member declaration
    8 |   get_return_object()
      |                     ^
      |                      ;
mutant.C:9:2: error: expected ';' after class definition
    9 | } class c {
      |  ^
      |  ;
mutant.C: In instantiation of 'struct std::coroutine_traits<std::c, int>':
mutant.C:13:12:   required from here
   13 |   co_await awaitable
      |            ^~~~~~~~~
mutant.C:3:9: error: 'using std::c::promise_type = class std::b' is private
within this context
    3 |   using promise_type = a : promise_type;
      |         ^~~~~~~~~~~~
mutant.C:10:9: note: declared private here
   10 |   using promise_type = b;
      |         ^~~~~~~~~~~~
mutant.C: In function 'std::c std::d(int)':
mutant.C:13:3: error: awaitable type 'int' is not a structure
   13 |   co_await awaitable
      |   ^~~~~~~~
mutant.C:13:21: error: expected '}' at end of input
   13 |   co_await awaitable
      |                     ^
mutant.C:12:57: note: to match this '{'
   12 | __attribute__((optimize(3))) auto d(int awaitable) -> c {
      |                                                         ^
mutant.C:12:35: error: no member named 'initial_suspend' in
'std::coroutine_traits<std::c, int>::promise_type' {aka 'std::b'}
   12 | __attribute__((optimize(3))) auto d(int awaitable) -> c {
      |                                   ^
mutant.C:12:35: error: no member named 'unhandled_exception' in
'std::coroutine_traits<std::c, int>::promise_type' {aka 'std::b'}
mutant.C:12:35: error: no member named 'final_suspend' in
'std::coroutine_traits<std::c, int>::promise_type' {aka 'std::b'}
mutant.C:13:21: error: 'int std::b::get_return_object()' is private within this
context
   13 |   co_await awaitable
      |                     ^
mutant.C:8:3: note: declared private here
    8 |   get_return_object()
      |   ^~~~~~~~~~~~~~~~~
mutant.C:13:21: error: could not convert '_Coro_gro' from 'int' to 'std::c'
   13 |   co_await awaitable
      |                     ^
      |                     |
      |                     int
mutant.C: At global scope:
mutant.C:13:21: error: expected '}' at end of input
mutant.C:1:15: note: to match this '{'
    1 | namespace std {
      |               ^
during GIMPLE pass: lower
mutant.C: In function 'void std::d(d(int)::_ZSt1di.Frame*)':
mutant.C:12:35: internal compiler error: in lower_stmt, at gimple-low.cc:724
   12 | __attribute__((optimize(3))) auto d(int awaitable) -> c {
      |                                   ^
0x576c1eb diagnostic_context::report_diagnostic(diagnostic_info*)
        ???:0
0x576cabd diagnostic_context::diagnostic_impl(rich_location*,
diagnostic_metadata const*, int, char const*, __va_list_tag (*) [1],
diagnostic_t)
        ???:0
0x578c98b internal_error(char const*, ...)
        ???:0
0x576d000 fancy_abort(char const*, int, char const*)
        ???:0
Please submit a full bug report, with preprocessed source (by using
-freport-bug).
Please include the complete backtrace with any bug report.
See <https://gcc.gnu.org/bugs/> for instructions.

Also ICE on trunk.
Compiler Explorer: https://godbolt.org/z/v48f8a4fn