* cfgloop.h (expected_loop_iterations_unbounded,

	expected_loop_iterations): Unconstify.
	* cfgloopanal.c (expected_loop_iterations_unbounded): Sanity check the
	profile with known upper bound; return 3 when profile is absent.
	(expected_loop_iterations): Update.


git-svn-id: https://gcc.gnu.org/svn/gcc/trunk@236511 138bc75d-0d04-0410-961f-82ee72b054a4

3 files changed, 35 insertions, 12 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 021f64e5bd8..7f5f87f293f 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,5 +1,13 @@
 2016-05-20  Jan Hubicka  <hubicka@ucw.cz>
 
+	* cfgloop.h (expected_loop_iterations_unbounded,
+	expected_loop_iterations): Unconstify.
+	* cfgloopanal.c (expected_loop_iterations_unbounded): Sanity check the
+	profile with known upper bound; return 3 when profile is absent.
+	(expected_loop_iterations): Update.
+
+2016-05-20  Jan Hubicka  <hubicka@ucw.cz>
+
 	* loop-doloop.c (doloop_optimize): Use get_estimated_loop_iterations_int
 	and get_max_loop_iterations_int.
 
diff --git a/gcc/cfgloop.h b/gcc/cfgloop.h
index 54e738f20f4..173fda84ba4 100644
--- a/gcc/cfgloop.h
+++ b/gcc/cfgloop.h
@@ -316,8 +316,8 @@ extern void verify_loop_structure (void);
 
 /* Loop analysis.  */
 extern bool just_once_each_iteration_p (const struct loop *, const_basic_block);
-gcov_type expected_loop_iterations_unbounded (const struct loop *);
-extern unsigned expected_loop_iterations (const struct loop *);
+gcov_type expected_loop_iterations_unbounded (struct loop *);
+extern unsigned expected_loop_iterations (struct loop *);
 extern rtx doloop_condition_get (rtx);
 
 void mark_loop_for_removal (loop_p);
diff --git a/gcc/cfgloopanal.c b/gcc/cfgloopanal.c
index 4d35820b729..938ac43879a 100644
--- a/gcc/cfgloopanal.c
+++ b/gcc/cfgloopanal.c
@@ -231,14 +231,20 @@ average_num_loop_insns (const struct loop *loop)
    value.  */
 
 gcov_type
-expected_loop_iterations_unbounded (const struct loop *loop)
+expected_loop_iterations_unbounded (struct loop *loop)
 {
   edge e;
   edge_iterator ei;
-
-  if (loop->latch->count || loop->header->count)
+  gcov_type expected;
+  
+
+  /* Average loop rolls about 3 times. If we have no profile at all, it is
+     best we can do.  */
+  if (profile_status_for_fn (cfun) == PROFILE_ABSENT)
+    expected = 3;
+  else if (loop->latch->count || loop->header->count)
     {
-      gcov_type count_in, count_latch, expected;
+      gcov_type count_in, count_latch;
 
       count_in = 0;
       count_latch = 0;
@@ -253,8 +259,6 @@ expected_loop_iterations_unbounded (const struct loop *loop)
 	expected = count_latch * 2;
       else
 	expected = (count_latch + count_in - 1) / count_in;
-
-      return expected;
     }
   else
     {
@@ -270,17 +274,28 @@ expected_loop_iterations_unbounded (const struct loop *loop)
 	  freq_in += EDGE_FREQUENCY (e);
 
       if (freq_in == 0)
-	return freq_latch * 2;
-
-      return (freq_latch + freq_in - 1) / freq_in;
+	{
+	  /* If we have no profile at all, expect 3 iterations.  */
+	  if (!freq_latch)
+	    expected = 3;
+	  else
+	    expected = freq_latch * 2;
+	}
+      else
+        expected = (freq_latch + freq_in - 1) / freq_in;
     }
+
+  HOST_WIDE_INT max = get_max_loop_iterations_int (loop);
+  if (max != -1 && max < expected)
+    return max;
+  return expected;
 }
 
 /* Returns expected number of LOOP iterations.  The returned value is bounded
    by REG_BR_PROB_BASE.  */
 
 unsigned
-expected_loop_iterations (const struct loop *loop)
+expected_loop_iterations (struct loop *loop)
 {
   gcov_type expected = expected_loop_iterations_unbounded (loop);
   return (expected > REG_BR_PROB_BASE ? REG_BR_PROB_BASE : expected);