| Message ID | ec513b23-24b4-250c-3ee8-2a0ee4b5beb4@vnet.ibm.com |
|---|---|
| State | New |
| Headers | show |
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), > >
On 6/29/17 8:58 AM, Richard Biener wrote: > On Thu, 29 Jun 2017, Peter Bergner wrote: >> 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 ... Yeah. I can implement that if you like...unless you want to... or already have. :-) Peter
On Thu, 29 Jun 2017, Peter Bergner wrote: > On 6/29/17 8:58 AM, Richard Biener wrote: > > On Thu, 29 Jun 2017, Peter Bergner wrote: > >> 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 ... > > Yeah. I can implement that if you like...unless you want to... > or already have. :-) Go ahead! Richard.
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),