On Thu, 29 Jun 2017, Peter Bergner wrote: > On 6/29/17 4:03 AM, Richard Biener wrote: > > > > This refactors things a bit to make CFG cleanup handle switches with > > just a default label. If we make sure to cleanup the CFG after > > group_case_labels removes cases with just __builtin_unreachable () > > inside then this fixes the ICE seen in PR81994 as well. > > > > I wonder if find_taken_edge should generally handle successors > > with __builtin_unreachable () -- OTOH that would get rid of those > > too early I guess. > > Should we offer an early out of group_case_labels_stmt() for the > fairly common case of new_size == old_size? There's no reason to > execute the compress labels loop if we didn't combine any of the > labels.
We can also merge both loops, counting new_size upwards, storing to label new_size if new_size != i ... > Peter > > > Index: gcc/tree-cfg.c > =================================================================== > --- gcc/tree-cfg.c (revision 249783) > +++ gcc/tree-cfg.c (working copy) > @@ -1747,6 +1747,11 @@ group_case_labels_stmt (gswitch *stmt) > } > } > > + gcc_assert (new_size <= old_size); > + > + if (new_size == old_size) > + return false; > + > /* Compress the case labels in the label vector, and adjust the > length of the vector. */ > for (i = 0, j = 0; i < new_size; i++) > @@ -1757,9 +1762,8 @@ group_case_labels_stmt (gswitch *stmt) > gimple_switch_label (stmt, j++)); > } > > - gcc_assert (new_size <= old_size); > gimple_switch_set_num_labels (stmt, new_size); > - return new_size < old_size; > + return true; > } > > /* Look for blocks ending in a multiway branch (a GIMPLE_SWITCH), > > -- Richard Biener <rguent...@suse.de> SUSE LINUX GmbH, GF: Felix Imendoerffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nuernberg)
