The patch set even probability to jump tables based on number of
cases which are handled on each edge.
gcc/ChangeLog:
2018-08-06 Martin Liska <mli...@suse.cz>
PR tree-optimization/86702
* tree-switch-conversion.c (jump_table_cluster::emit):
Make probabilities even for values in jump table
according to number of cases handled.
(switch_decision_tree::compute_cases_per_edge): Pass
argument to reset_out_edges_aux function.
(switch_decision_tree::analyze_switch_statement): Likewise.
* tree-switch-conversion.h (switch_decision_tree::reset_out_edges_aux):
Make it static.
---
gcc/tree-switch-conversion.c | 40 ++++++++++++++++++++++++++++++++++--
gcc/tree-switch-conversion.h | 11 +++++-----
2 files changed, 43 insertions(+), 8 deletions(-)
diff --git a/gcc/tree-switch-conversion.c b/gcc/tree-switch-conversion.c
index 492cd365a30..0b5c93118f6 100644
--- a/gcc/tree-switch-conversion.c
+++ b/gcc/tree-switch-conversion.c
@@ -1064,6 +1064,9 @@ void
jump_table_cluster::emit (tree index_expr, tree,
tree default_label_expr, basic_block default_bb)
{
+ unsigned HOST_WIDE_INT range = get_range (get_low (), get_high ());
+ unsigned HOST_WIDE_INT nondefault_range = 0;
+
/* For jump table we just emit a new gswitch statement that will
be latter lowered to jump table. */
auto_vec <tree> labels;
@@ -1080,6 +1083,39 @@ jump_table_cluster::emit (tree index_expr, tree,
unshare_expr (default_label_expr), labels);
gimple_stmt_iterator gsi = gsi_start_bb (m_case_bb);
gsi_insert_after (&gsi, s, GSI_NEW_STMT);
+
+ /* Set up even probabilities for all cases. */
+ for (unsigned i = 0; i < m_cases.length (); i++)
+ {
+ simple_cluster *sc = static_cast<simple_cluster *> (m_cases[i]);
+ edge case_edge = find_edge (m_case_bb, sc->m_case_bb);
+ unsigned HOST_WIDE_INT case_range
+ = sc->get_range (sc->get_low (), sc->get_high ());
+ nondefault_range += case_range;
+
+ /* case_edge->aux is number of values in a jump-table that are covered
+ by the case_edge. */
+ case_edge->aux = (void *) ((intptr_t) (case_edge->aux) + case_range);
+ }
+
+ edge default_edge = gimple_switch_default_edge (s);
+ default_edge->probability = profile_probability::never ();
+
+ for (unsigned i = 0; i < m_cases.length (); i++)
+ {
+ simple_cluster *sc = static_cast<simple_cluster *> (m_cases[i]);
+ edge case_edge = find_edge (m_case_bb, sc->m_case_bb);
+ case_edge->probability
+ = profile_probability::always ().apply_scale ((intptr_t)case_edge->aux,
+ range);
+ }
+
+ /* Number of non-default values is probability of default edge. */
+ default_edge->probability
+ += profile_probability::always ().apply_scale (nondefault_range,
+ range).invert ();
+
+ switch_decision_tree::reset_out_edges_aux (s);
}
/* Find jump tables of given CLUSTERS, where all members of the vector
@@ -1571,7 +1607,7 @@ bit_test_cluster::hoist_edge_and_branch_if_true (gimple_stmt_iterator *gsip,
void
switch_decision_tree::compute_cases_per_edge ()
{
- reset_out_edges_aux ();
+ reset_out_edges_aux (m_switch);
int ncases = gimple_switch_num_labels (m_switch);
for (int i = ncases - 1; i >= 1; --i)
{
@@ -1614,7 +1650,7 @@ switch_decision_tree::analyze_switch_statement ()
m_case_bbs.quick_push (case_edge->dest);
}
- reset_out_edges_aux ();
+ reset_out_edges_aux (m_switch);
/* Find jump table clusters. */
vec<cluster *> output = jump_table_cluster::find_jump_tables (clusters);
diff --git a/gcc/tree-switch-conversion.h b/gcc/tree-switch-conversion.h
index 4beac785f05..af2f47a07e6 100644
--- a/gcc/tree-switch-conversion.h
+++ b/gcc/tree-switch-conversion.h
@@ -513,10 +513,6 @@ struct switch_decision_tree
/* Attempt to expand CLUSTERS as a decision tree. Return true when
expanded. */
bool try_switch_expansion (vec<cluster *> &clusters);
-
- /* Reset the aux field of all outgoing edges of switch basic block. */
- inline void reset_out_edges_aux ();
-
/* Compute the number of case labels that correspond to each outgoing edge of
switch statement. Record this information in the aux field of the edge.
*/
@@ -576,6 +572,9 @@ struct switch_decision_tree
basic_block label_bb,
profile_probability prob);
+ /* Reset the aux field of all outgoing edges of switch basic block. */
+ static inline void reset_out_edges_aux (gswitch *swtch);
+
/* Switch statement. */
gswitch *m_switch;
@@ -838,9 +837,9 @@ struct switch_conversion
};
void
-switch_decision_tree::reset_out_edges_aux ()
+switch_decision_tree::reset_out_edges_aux (gswitch *swtch)
{
- basic_block bb = gimple_bb (m_switch);
+ basic_block bb = gimple_bb (swtch);
edge e;
edge_iterator ei;
FOR_EACH_EDGE (e, ei, bb->succs)
