[Bug c++/120243] [15/16 Regression] Exception rethrown from coroutine promise type unhandled_exception not caught under -O1

[iains at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120243

--- Comment #5 from Iain Sandoe <iains at gcc dot gnu.org> ---
we synthesise the same code, but the revised builder uses
start_preparsed_function()/finish_function() and the latter introduces an extra
try block.  Investigating.