Check TYPE_OVERFLOW_WRAPS for parloops reductions

2015-07-23  Tom de Vries  <tom@codesourcery.com>

	* tree-parloops.c (gather_scalar_reductions): Add arg to call to
	vect_force_simple_reduction.
	* tree-vect-loop.c (vect_analyze_scalar_cycles_1): Same.
	(vect_is_simple_reduction_1): Add and handle
	need_wrapping_integral_overflow parameter.
	(vect_is_simple_reduction, vect_force_simple_reduction): Add and pass
	need_wrapping_integral_overflow parameter.
	(vectorizable_reduction): Add arg to call to vect_is_simple_reduction.
	* tree-vectorizer.h (vect_force_simple_reduction): Add parameter to decl.

	* gcc.dg/autopar/outer-4.c: Add xfail.
	* gcc.dg/autopar/outer-5.c: Same.
	* gcc.dg/autopar/outer-6.c: Same.
	* gcc.dg/autopar/reduc-2.c: Same.
	* gcc.dg/autopar/reduc-2char.c: Same.
	* gcc.dg/autopar/reduc-2short.c: Same.
	* gcc.dg/autopar/reduc-8.c: Same.
	* gcc.dg/autopar/uns-outer-4.c: New test.
	* gcc.dg/autopar/uns-outer-5.c: New test.
	* gcc.dg/autopar/uns-outer-6.c: New test.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@226107 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 30 insertions, 14 deletions

diff --git a/gcc/tree-vect-loop.c b/gcc/tree-vect-loop.c
index 9145dbf19e1..c31bfbdbad4 100644
--- a/gcc/tree-vect-loop.c
+++ b/gcc/tree-vect-loop.c
@@ -715,7 +715,7 @@ vect_analyze_scalar_cycles_1 (loop_vec_info loop_vinfo, struct loop *loop)
 
       nested_cycle = (loop != LOOP_VINFO_LOOP (loop_vinfo));
       reduc_stmt = vect_force_simple_reduction (loop_vinfo, phi, !nested_cycle,
-						&double_reduc);
+						&double_reduc, false);
       if (reduc_stmt)
         {
           if (double_reduc)
@@ -2339,7 +2339,7 @@ vect_is_slp_reduction (loop_vec_info loop_info, gimple phi, gimple first_stmt)
 static gimple
 vect_is_simple_reduction_1 (loop_vec_info loop_info, gimple phi,
 			    bool check_reduction, bool *double_reduc,
-			    bool modify)
+			    bool modify, bool need_wrapping_integral_overflow)
 {
   struct loop *loop = (gimple_bb (phi))->loop_father;
   struct loop *vect_loop = LOOP_VINFO_LOOP (loop_info);
@@ -2613,14 +2613,26 @@ vect_is_simple_reduction_1 (loop_vec_info loop_info, gimple phi,
 			"reduction: unsafe fp math optimization: ");
       return NULL;
     }
-  else if (INTEGRAL_TYPE_P (type) && TYPE_OVERFLOW_TRAPS (type)
-	   && check_reduction)
+  else if (INTEGRAL_TYPE_P (type) && check_reduction)
     {
-      /* Changing the order of operations changes the semantics.  */
-      if (dump_enabled_p ())
-	report_vect_op (MSG_MISSED_OPTIMIZATION, def_stmt,
-			"reduction: unsafe int math optimization: ");
-      return NULL;
+      if (TYPE_OVERFLOW_TRAPS (type))
+	{
+	  /* Changing the order of operations changes the semantics.  */
+	  if (dump_enabled_p ())
+	    report_vect_op (MSG_MISSED_OPTIMIZATION, def_stmt,
+			    "reduction: unsafe int math optimization"
+			    " (overflow traps): ");
+	  return NULL;
+	}
+      if (need_wrapping_integral_overflow && !TYPE_OVERFLOW_WRAPS (type))
+	{
+	  /* Changing the order of operations changes the semantics.  */
+	  if (dump_enabled_p ())
+	    report_vect_op (MSG_MISSED_OPTIMIZATION, def_stmt,
+			    "reduction: unsafe int math optimization"
+			    " (overflow doesn't wrap): ");
+	  return NULL;
+	}
     }
   else if (SAT_FIXED_POINT_TYPE_P (type) && check_reduction)
     {
@@ -2749,10 +2761,12 @@ vect_is_simple_reduction_1 (loop_vec_info loop_info, gimple phi,
 
 static gimple
 vect_is_simple_reduction (loop_vec_info loop_info, gimple phi,
-                          bool check_reduction, bool *double_reduc)
+			  bool check_reduction, bool *double_reduc,
+			  bool need_wrapping_integral_overflow)
 {
   return vect_is_simple_reduction_1 (loop_info, phi, check_reduction,
-				     double_reduc, false);
+				     double_reduc, false,
+				     need_wrapping_integral_overflow);
 }
 
 /* Wrapper around vect_is_simple_reduction_1, which will modify code
@@ -2761,10 +2775,12 @@ vect_is_simple_reduction (loop_vec_info loop_info, gimple phi,
 
 gimple
 vect_force_simple_reduction (loop_vec_info loop_info, gimple phi,
-                          bool check_reduction, bool *double_reduc)
+			     bool check_reduction, bool *double_reduc,
+			     bool need_wrapping_integral_overflow)
 {
   return vect_is_simple_reduction_1 (loop_info, phi, check_reduction,
-				     double_reduc, true);
+				     double_reduc, true,
+				     need_wrapping_integral_overflow);
 }
 
 /* Calculate cost of peeling the loop PEEL_ITERS_PROLOGUE times.  */
@@ -5074,7 +5090,7 @@ vectorizable_reduction (gimple stmt, gimple_stmt_iterator *gsi,
     }
 
   gimple tmp = vect_is_simple_reduction (loop_vinfo, reduc_def_stmt,
-					 !nested_cycle, &dummy);
+					 !nested_cycle, &dummy, false);
   if (orig_stmt)
     gcc_assert (tmp == orig_stmt
 		|| GROUP_FIRST_ELEMENT (vinfo_for_stmt (tmp)) == orig_stmt);