[PATCH] Generalize get_most_common_single_value to return k_th value & count

[Xiong Hu Luo]

Currently get_most_common_single_value could only return the max hist
<value, count>, add two paramter to enable this function return kth
value if needed.

gcc/ChangeLog:

        2019-07-15  Xiong Hu Luo  <luo...@linux.ibm.com>

        * value-prof.c (get_most_common_single_value): Add input params
        k_th and k, return the k_th <value, count> if k_th is true.
        * value-prof.h (get_most_common_single_value): Add input params
        k_th and k, default to false.
---
 gcc/value-prof.c | 16 ++++++++++++----
 gcc/value-prof.h |  7 +++----
 2 files changed, 15 insertions(+), 8 deletions(-)

diff --git a/gcc/value-prof.c b/gcc/value-prof.c
index 32e6ddd8165..e1a3e0bd4b5 100644
--- a/gcc/value-prof.c
+++ b/gcc/value-prof.c
@@ -719,9 +719,9 @@ gimple_divmod_fixed_value (gassign *stmt, tree value, 
profile_probability prob,
 
 bool
 get_most_common_single_value (gimple *stmt, const char *counter_type,
-                             histogram_value hist,
-                             gcov_type *value, gcov_type *count,
-                             gcov_type *all)
+                             histogram_value hist, gcov_type *value,
+                             gcov_type *count, gcov_type *all, bool k_th,
+                             unsigned k)
 {
   if (hist->hvalue.counters[2] == -1)
     return false;
@@ -743,7 +743,15 @@ get_most_common_single_value (gimple *stmt, const char 
*counter_type,
 
       *all = read_all;
 
-      if (c > *count)
+      /* Return the kth value in hist instead of the max value for indirect
+        multiple call usage.  */
+      if (k_th && i == k)
+       {
+         *value = v;
+         *count = c;
+         break;
+      }
+      else if (c > *count)
        {
          *value = v;
          *count = c;
diff --git a/gcc/value-prof.h b/gcc/value-prof.h
index ca846d08cbd..0a064a71f7d 100644
--- a/gcc/value-prof.h
+++ b/gcc/value-prof.h
@@ -90,10 +90,9 @@ void stringop_block_profile (gimple *, unsigned int *, 
HOST_WIDE_INT *);
 gcall *gimple_ic (gcall *, struct cgraph_node *, profile_probability);
 bool check_ic_target (gcall *, struct cgraph_node *);
 bool get_most_common_single_value (gimple *stmt, const char *counter_type,
-                                  histogram_value hist,
-                                  gcov_type *value, gcov_type *count,
-                                  gcov_type *all);
-
+                                  histogram_value hist, gcov_type *value,
+                                  gcov_type *count, gcov_type *all,
+                                  bool k_th = false, unsigned k = 0);
 
 /* In tree-profile.c.  */
 extern void gimple_init_gcov_profiler (void);
-- 
2.22.0.428.g6d5b264208