Re: tail call optimizations

[Jason Merrill <jason at cygnus dot com>]

>>>>> Jeffrey A Law <law@cygnus.com> writes:

 >> Is there a problem I don't see where if you have
 >> 
 >> int foo ()  { bar(); }
 >> 
 >> and bar() throws, you can't just pass the exception up to foo's
 >> caller, just as if foo's caller had called bar directly?

 > I'm not sure enough about EH semantics to know if this situation is even
 > possible.

 > If bar can throw, don't we have to assume that foo can throw?

Yes.

 > If so, then no tail call optimization is possible.

Why not?  An exception thrown out of bar would just propagate out to foo's
caller, as if it had been thrown from foo.

It doesn't matter if a call can throw; it only matters if we want to try
to catch the exception.

Jason