[tree-ssa] Fun with exceptions -- opinions needed

[Andrew Haley]

Diego Novillo writes:
 > On Fri, 2003-06-13 at 19:47, law@redhat.com wrote:
 > 
 > >             i = get (strm.5)
 > >
 > Huh, I thought the gimplifier was already gimplifying expressions that
 > may throw into
 > 
 > 		tmp = <expr>;
 > 		i = tmp;
 > 
 > I don't really see a clean way around creating a new temporary.  I don't
 > think we want to have MAY_MODIFY_EXPR in GIMPLE :)
 > 
 > The flow graph builder is already handling calls and indirect refs. 
 > Shouldn't we have an EXPR_MAY_THROW_P attribute?  Java, can throw just
 > about anywhere, IIRC.

In Java we always know which expressions may throw; it would be good
if the front end could communicate this through to the back end.  An
EXPR_MAY_THROW_P attribute is an excellent idea.

Andrew.