> > if (!single_succ_p (bb))
> > - return;
> > + {
> > + int num_eh, num_other;
> > + bb_get_succ_edge_count (bb, num_eh, num_other);
> > + /* Allow EH edges so that we can give a better
> > + error message later. */
>
> Please instead use has_abnormal_or_eh_outgoing_edge_p (bb) instead
That's not equivalent, need a num_other == 1 check too.
Do you want me to move the function to a generic place?
> to avoid adding another function like this. Also only continue searching
> for a musttail call if cfun->has_musttail
Done (although I must say I liked the better dump messages even for non
tailcall)
> > if (gimple_references_memory_p (stmt)
> > || gimple_has_volatile_ops (stmt))
> > - return;
> > + {
> > + bad_stmt = true;
>
> break here when !cfun->has_musttail?
Done.
> > if (ass_var
> > && !is_gimple_reg (ass_var)
> > && !auto_var_in_fn_p (ass_var, cfun->decl))
> > - return;
> > + {
> > + maybe_error_musttail (call, _("return value in memory"));
> > + return;
> > + }
> > +
> > + if (cfun->calls_setjmp)
> > + {
> > + maybe_error_musttail (call, _("caller uses setjmp"));
> > + return;
> > + }
> >
> > /* If the call might throw an exception that wouldn't propagate out of
> > cfun, we can't transform to a tail or sibling call (82081). */
> > - if (stmt_could_throw_p (cfun, stmt)
> > - && !stmt_can_throw_external (cfun, stmt))
> > + if ((stmt_could_throw_p (cfun, stmt)
> > + && !stmt_can_throw_external (cfun, stmt)) || !single_succ_p (bb))
>
> This reports for the found stmt while above we reject any intermediate
> non-fallthru control flow. I would suggest to, in the above BB check,
> record a gimple *last = last_stmt (bb) and if last == stmt report this reason
> but otherwise "control altering statement between call and return"?
Ok. I reported "code between call and return". I don't think there
since "control" would imply control flow.
Also there is no last_stmt () or did I miss it? It couldn't be used
anyways because it still needs to skip the nops etc. But the backwards
loop can easily discover it.
BTW I suspect some of the checks are redundant but it is hard to really
prove it, so I left everything in place.
> > + maybe_error_musttail (call,
> > + _("call may throw exception that does not
> > propagate"));
> > return;
> > + }
> >
> > /* If the function returns a value, then at present, the tail call
> > must return the same type of value. There is conceptually a copy
> > @@ -524,7 +593,10 @@ find_tail_calls (basic_block bb, struct tailcall
> > **ret, bool only_musttail)
> > if (result_decl
> > && may_be_aliased (result_decl)
> > && ref_maybe_used_by_stmt_p (call, result_decl, false))
> > - return;
> > + {
> > + maybe_error_musttail (call, _("tail call must be same type"));
>
> ? "call uses the return slot"?
>
> Otherwise looks OK.
Done. Although I'm not sure what a return slot is, but maybe the users
can figure it out)
-Andi
