[Bug middle-end/82504] Optimize away exception allocation and throws handled by catch(...){}

[antoshkka at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82504

--- Comment #4 from Antony Polukhin <antoshkka at gmail dot com> ---
This ticket is a subset of PR53294. PR53294 about any catch expression
optimizations, which could be harder than optimizing away catch(...) {} and
catch(...) { return X; }