https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106126
--- Comment #13 from luoxhu at gcc dot gnu.org ---
Otherwise we need record first_bb when conditions_in_bbs->is_empty, then check
that in is_beneficial, ordered_remove the info entry if that bb is not the
first "if condition" with side_effect statement in it, the fix would be as
below, but I am not sure whether it is worth&correct way doing this to handle
both PR105740 and PR106126?
git diff
diff --git a/gcc/gimple-if-to-switch.cc b/gcc/gimple-if-to-switch.cc
index f7b0b02628b..44bb0228856 100644
--- a/gcc/gimple-if-to-switch.cc
+++ b/gcc/gimple-if-to-switch.cc
@@ -63,7 +63,7 @@ struct condition_info
condition_info (gcond *cond): m_cond (cond), m_bb (gimple_bb (cond)),
m_forwarder_bb (NULL), m_ranges (), m_true_edge (NULL), m_false_edge
(NULL),
- m_true_edge_phi_mapping (), m_false_edge_phi_mapping ()
+ m_true_edge_phi_mapping (), m_false_edge_phi_mapping (), first_bb(false)
{
m_ranges.create (0);
}
@@ -80,6 +80,7 @@ struct condition_info
edge m_false_edge;
mapping_vec m_true_edge_phi_mapping;
mapping_vec m_false_edge_phi_mapping;
+ bool first_bb;
};
/* Recond PHI mapping for an original edge E and save these into vector VEC.
*/
@@ -194,6 +195,16 @@ if_chain::is_beneficial ()
auto_vec<cluster *> clusters;
clusters.create (m_entries.length ());
+ for (unsigned i = 0; i < m_entries.length (); i++)
+ {
+ condition_info *info = m_entries[i];
+ if (info->first_bb && i != 0 && !no_side_effect_bb (info->m_bb))
+ {
+ m_entries.ordered_remove (i);
+ break;
+ }
+ }
+
for (unsigned i = 0; i < m_entries.length (); i++)
{
condition_info *info = m_entries[i];
@@ -397,6 +408,8 @@ find_conditions (basic_block bb,
tree_code code = gimple_cond_code (cond);
condition_info *info = new condition_info (cond);
+ if (conditions_in_bbs->is_empty ())
+ info->first_bb = true;
