[PR42245] Recompute top order after redirecting an edge

[Vladimir Makarov]

Alexander Monakov wrote:
> This is an updated patch for the same problem, fixing a shortcoming in a
> previously sent implementation.
>
> We 'forgot' to recompute topological order if it was invalidated in
> tidy_control_flow but not in maybe_tidy_empty_bb called from that 
> function. Fixed by passing recompute_toporder_p to the latter.  We 
> have also made maybe_tidy_empty_bb static by moving the only external 
> caller into the same file).
>
> Incremental patch is archived at
> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42245#c7
>
> Thanks.
>
> 2010-01-13  Andrey Belevantsev  <abel@ispras.ru>
>         Alexander Monakov  <amonakov@ispras.ru>
>
>     PR middle-end/42245
>     * sel-sched-ir.c (sel_recompute_toporder): New.  Use it...
>     (maybe_tidy_empty_bb): ... here.  Make static.  Add new
>     argument.  Update all callers.
>     (tidy_control_flow): ... and here.  Recompute topological order
>     of basic blocks in region if necessary.
>     (sel_redirect_edge_and_branch): Change return type.  Return true
>     if topological order might have been invalidated.
>     (purge_empty_blocks): Export and move from...
>     * sel-sched.c (purge_empty_blocks): ... here.
>     * sel-sched-ir.h (sel_redirect_edge_and_branch): Update prototype.
>         (maybe_tidy_empty_bb): Delete prototype.
>     (purge_empty_blocks): Declare.
>
>     * gcc.dg/pr42245.c: New.
>     * gcc.dg/pr42245-2.c: New.
The patch is ok for the trunk.  Thanks.