modulo-sched: fix branch rescheduling issue (PR92591)

	PR rtl-optimization/92591
	* modulo-sched.c (ps_add_node_check_conflicts): Improve checking
	for history > 0 case.

testsuite:

	PR rtl-optimization/92591
	* gcc.dg/pr92951-1.c: New test.
	* gcc.dg/pr92951-2.c: New test.

From-SVN: r279377

5 files changed, 53 insertions, 15 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 56d05cc..f8a56a4 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,5 +1,11 @@
 2019-12-13  Roman Zhuykov  <zhroma@ispras.ru>
 
+	PR rtl-optimization/92591
+	* modulo-sched.c (ps_add_node_check_conflicts): Improve checking
+	for history > 0 case.
+
+2019-12-13  Roman Zhuykov  <zhroma@ispras.ru>
+
 	* modulo-sched.c (sms_schedule): Use param_sms_max_ii_factor
 	value instead of macro.  Adjust comment.
 	(sms_schedule_by_order): Use parameter value without macro.
@@ -8,6 +14,7 @@
 
 2019-12-13  Roman Zhuykov  <zhroma@ispras.ru>
 
+	PR rtl-optimization/90001
 	* ddg.c (create_ddg): Init max_dist array for each node.
 	(free_ddg): Free max_dist array.
 	(create_ddg_edge): Use bool field instead of aux union.
diff --git a/gcc/modulo-sched.c b/gcc/modulo-sched.c
index 2dc9af7..ddc2874 100644
--- a/gcc/modulo-sched.c
+++ b/gcc/modulo-sched.c
@@ -3197,7 +3197,7 @@ ps_add_node_check_conflicts (partial_schedule_ptr ps, int n,
    			     int c, sbitmap must_precede,
 			     sbitmap must_follow)
 {
-  int has_conflicts = 0;
+  int i, first, amount, has_conflicts = 0;
   ps_insn_ptr ps_i;
 
   /* First add the node to the PS, if this succeeds check for
@@ -3205,23 +3205,32 @@ ps_add_node_check_conflicts (partial_schedule_ptr ps, int n,
   if (! (ps_i = add_node_to_ps (ps, n, c, must_precede, must_follow)))
     return NULL; /* Failed to insert the node at the given cycle.  */
 
-  has_conflicts = ps_has_conflicts (ps, c, c)
-		  || (ps->history > 0
-		      && ps_has_conflicts (ps,
-					   c - ps->history,
-					   c + ps->history));
-
-  /* Try different issue slots to find one that the given node can be
-     scheduled in without conflicts.  */
-  while (has_conflicts)
+  while (1)
     {
+      has_conflicts = ps_has_conflicts (ps, c, c);
+      if (ps->history > 0 && !has_conflicts)
+	{
+	  /* Check all 2h+1 intervals, starting from c-2h..c up to c..2h,
+	     but not more than ii intervals.  */
+	  first = c - ps->history;
+	  amount = 2 * ps->history + 1;
+	  if (amount > ps->ii)
+	    amount = ps->ii;
+	  for (i = first; i < first + amount; i++)
+	    {
+	      has_conflicts = ps_has_conflicts (ps,
+						i - ps->history,
+						i + ps->history);
+	      if (has_conflicts)
+		break;
+	    }
+	}
+      if (!has_conflicts)
+	break;
+      /* Try different issue slots to find one that the given node can be
+	 scheduled in without conflicts.  */
       if (! ps_insn_advance_column (ps, ps_i, must_follow))
 	break;
-      has_conflicts = ps_has_conflicts (ps, c, c)
-		      || (ps->history > 0
-			  && ps_has_conflicts (ps,
-					       c - ps->history,
-					       c + ps->history));
     }
 
   if (has_conflicts)
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 7ea9f58..2a4d9a0 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,9 @@
+2019-12-13  Roman Zhuykov  <zhroma@ispras.ru>
+
+	PR rtl-optimization/92591
+	* gcc.dg/pr92951-1.c: New test.
+	* gcc.dg/pr92951-2.c: New test.
+
 2019-12-13  Dennis Zhang  <dennis.zhang@arm.com>
 
 	* gcc.target/aarch64/pragma_cpp_predefs_2.c: Add tests for i8mm
diff --git a/gcc/testsuite/gcc.dg/pr92951-1.c b/gcc/testsuite/gcc.dg/pr92951-1.c
new file mode 100644
index 0000000..0f9365d
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr92951-1.c
@@ -0,0 +1,11 @@
+/* PR rtl-optimization/92591 */
+/* { dg-do compile } */
+/* { dg-options "-O2 -fmodulo-sched -fweb -fno-dce -fno-ivopts -fno-sched-pressure -fno-tree-loop-distribute-patterns --param sms-dfa-history=1" } */
+/* { dg-additional-options "-mcpu=e500mc" { target { powerpc-*-* } } } */
+
+void
+wf (char *mr, int tc)
+{
+  while (tc-- > 0)
+    *mr++ = 0;
+}
diff --git a/gcc/testsuite/gcc.dg/pr92951-2.c b/gcc/testsuite/gcc.dg/pr92951-2.c
new file mode 100644
index 0000000..04a8092
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr92951-2.c
@@ -0,0 +1,5 @@
+/* PR rtl-optimization/92591 */
+/* { dg-do compile } */
+/* { dg-options "-Os -fmodulo-sched -fmodulo-sched-allow-regmoves --param sms-dfa-history=8" } */
+
+#include "../gcc.c-torture/execute/pr61682.c"