Re: PR middle-end/28779

[Jan Hubicka <hubicka at ucw dot cz>]

> 
> I remember this is somehow "carefuly" crafted to not cause ICEs when due to
> miscounting here we end up with ICE in inliner when inlined size goes
> negative ;)

Yep, the testcase in PR28779 is precisely about inline size getting
negative due to mismatch with what inliner does. This happens because
of what is just declaration at esitmate_num_insns becomes real function
at early inlining time.  This won't happen with unit-at-a-time, since we
analyze after parsing everything unless --combine is used. Non
unit-at-a-time compilation is affected by same problem however.

This version attempts to be crafted just bit more "carefuly" than
former:  The former fix replaced CALL_EXPR arguments walk by walk of
DECL_ARGUMENTS when available and CALL_EXPR as fallback. Due to thinko
it also eliminated the walk completely for functions with prototype but
no definition.  This fix keeps DECL_ARGUMENTS walk but adds TYPE_ARGS
walk that is used when prototype is around keeping CALL_EXPR walk as
fallback for functions with no definition nor prototype.

Honza


> 
> So I prefer that you put this on trunk first once we have branched.
> We can consider
> backporting to 4.3.1 if it turns out to be safe ;)
> 
> Richard.
> 
> >         PR middle-end/28779
> >         * tree-inline.c (estimate_num_insns_1): Fix counting of cost of call_expr.
> > Index: tree-inline.c
> > ===================================================================
> > *** tree-inline.c       (revision 132380)
> > --- tree-inline.c       (working copy)
> > *************** estimate_num_insns_1 (tree *tp, int *wal
> > *** 2434,2439 ****
> > --- 2434,2444 ----
> >       case CALL_EXPR:
> >         {
> >         tree decl = get_callee_fndecl (x);
> > +       tree addr = CALL_EXPR_FN (x);
> > +       tree funtype = TREE_TYPE (addr);
> > +
> > +       gcc_assert (POINTER_TYPE_P (funtype));
> > +       funtype = TREE_TYPE (funtype);
> >
> >         if (decl && DECL_BUILT_IN_CLASS (decl) == BUILT_IN_MD)
> >           cost = d->weights->target_builtin_call_cost;
> > *************** estimate_num_insns_1 (tree *tp, int *wal
> > *** 2456,2476 ****
> >               break;
> >             }
> >
> >         /* Our cost must be kept in sync with cgraph_estimate_size_after_inlining
> > !          that does use function declaration to figure out the arguments.  */
> > !       if (!decl)
> >           {
> >             tree a;
> >             call_expr_arg_iterator iter;
> >             FOR_EACH_CALL_EXPR_ARG (a, iter, x)
> >               d->count += estimate_move_cost (TREE_TYPE (a));
> >           }
> > -       else
> > -         {
> > -           tree arg;
> > -           for (arg = DECL_ARGUMENTS (decl); arg; arg = TREE_CHAIN (arg))
> > -             d->count += estimate_move_cost (TREE_TYPE (arg));
> > -         }
> >
> >         d->count += cost;
> >         break;
> > --- 2461,2494 ----
> >               break;
> >             }
> >
> > +       if (decl)
> > +         funtype = TREE_TYPE (decl);
> > +
> >         /* Our cost must be kept in sync with cgraph_estimate_size_after_inlining
> > !          that does use function declaration to figure out the arguments.
> > !
> > !          When we deal with function with no body nor prototype, base estimates on
> > !          actual parameters of the call expression.  Otherwise use either the actual
> > !          arguments types or function declaration for more precise answer.  */
> > !       if (decl && DECL_ARGUMENTS (decl))
> > !         {
> > !           tree arg;
> > !           for (arg = DECL_ARGUMENTS (decl); arg; arg = TREE_CHAIN (arg))
> > !             d->count += estimate_move_cost (TREE_TYPE (arg));
> > !         }
> > !       else if (funtype && prototype_p (funtype))
> > !         {
> > !           tree t;
> > !           for (t = TYPE_ARG_TYPES (funtype); t; t = TREE_CHAIN (t))
> > !             d->count += estimate_move_cost (TREE_VALUE (t));
> > !         }
> > !       else
> >           {
> >             tree a;
> >             call_expr_arg_iterator iter;
> >             FOR_EACH_CALL_EXPR_ARG (a, iter, x)
> >               d->count += estimate_move_cost (TREE_TYPE (a));
> >           }
> >
> >         d->count += cost;
> >         break;
> >