A latent bug - use of BRANCH_EDGE on trees.

[Zdenek Dvorak]

Hello,

> > yes, this indeed is a problem.  There are several solutions:
> > 
> > 1) Let the caller pass the edge corresponding to the current
> >    BRANCH_EDGE (switch_bb) to loopify
> > 2) Let BRANCH_EDGE check ir_type and use EDGE_{TRUE,FALSE}_FLAG for
> >    trees.
> > 3) Let EDGE_FALSE_FLAG == EDGE_FALLTHRU
> > 
> > I do not have any special preference here.
> 
> Or
> 
> 4. Do the following.
> 
>   if (ir_type ())
>     /* We are in trees.  */
>     true_edge = ((EDGE_SUCC (switch_bb, 0)->flags & EDGE_TRUE_VALUE)
> 		 ? EDGE_SUCC (switch_bb, 0)
> 		 : EDGE_SUCC (switch_bb, 1));
>   else
>     /* We are in RTL.  */
>     true_edge = BRANCH_EDGE (switch_bb);
> 
>   loop_redirect_edge (true_edge, succ_bb);
> 
> I guess!?

yes, but in general it is preferred not to expose such IR dependencies
directly in the high-level functions (i.e. the equivalent solution
2) is better).

Zdenek