[Bug c++/126884] New: [coroutine] incorrect coroutine promise lifetime when unhandled_exception() rethrows

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=126884

            Bug ID: 126884
           Summary: [coroutine] incorrect coroutine promise lifetime when
                    unhandled_exception()  rethrows
           Product: gcc
           Version: 14.3.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: bootmgr at 163 dot com
  Target Milestone: ---

This is an additional issue found while investigating the example from
https://github.com/cplusplus/CWG/issues/574.
Godbolt reproducer:  
https://godbolt.org/z/E75zs44cd
Starting with GCC 14.3, when  promise_type::unhandled_exception()  rethrows the
current exception, the coroutine appears to construct the promise twice but
destroy it only once. The generated behavior differs from GCC 14.2 and from
Clang/MSVC.
This looks like a regression in coroutine frame or promise lifetime handling,
specifically when an exception escapes from unhandled_exception().