re PR tree-optimization/69783 (Loop is not vectorized after r233212)

2016-02-15  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/69783
	* tree-vect-data-refs.c (vect_prune_runtime_alias_test_list):
	Add trivially correct cases.

	* gcc.dg/vect/pr69783.c: New testcase.

From-SVN: r233420

gcc/ChangeLog

+2016-02-15  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/69783
+	* tree-vect-data-refs.c (vect_prune_runtime_alias_test_list):
+	Add trivially correct cases.
+
 2016-02-15  Tom de Vries  <tom@codesourcery.com>
 
 	PR lto/69655

gcc/testsuite/ChangeLog

 2016-02-15  Richard Biener  <rguenther@suse.de>
 
+	PR tree-optimization/69783
+	* gcc.dg/vect/pr69783.c: New testcase.
+
+2016-02-15  Richard Biener  <rguenther@suse.de>
+
 	PR tree-optimization/69776
 	* gcc.dg/torture/pr69776.c: New testcase.
 

gcc/testsuite/gcc.dg/vect/pr69783.c

+/* { dg-do compile } */
+/* { dg-require-effective-target vect_float } */
+/* { dg-additional-options "-Ofast -funroll-loops" } */
+
+#define NXX 516
+#define NYY 516
+#define IND(x,y) ((x) + (y)*NXX)
+float **In, **Out, **V;
+
+void foo(int I, int J, int K1, int K2, int L1, int L2 )
+{
+  for(int i=0; i < I; i++)
+    {
+      float *v = V[i];
+
+      for(int j=0; j < J; j++)
+	{
+	  float *in = In[j];
+	  float *out = Out[j];
+	  for(int l=L1; l<L2; l++)
+	    {
+	      for(int k=K1; k<K2; k++)
+		{
+		  float sum = 0;
+		  int offset = 0;
+		  for(int m=-2; m<=2; m++)
+		    {
+		      for(int n=-2; n<=2; n++, offset++)
+			sum += in[IND((k+n), (l+m))] * v[offset];
+		    }
+		  out[IND(k,l)] = sum;
+		}
+	    }
+
+	}
+    }
+}
+
+/* { dg-final { scan-tree-dump "improved number of alias checks from \[0-9\]* to 2" "vect" } } */

gcc/tree-vect-data-refs.c

@@ -3089,6 +3089,30 @@ vect_prune_runtime_alias_test_list (loop_vec_info loop_vinfo)
 	    = tree_to_shwi (dr_a2->offset) - tree_to_shwi (dr_a1->offset);
 
 
+	  bool do_remove = false;
+
+	  /* If the left segment does not extend beyond the start of the
+	     right segment the new segment length is that of the right
+	     plus the segment distance.  */
+	  if (tree_fits_uhwi_p (dr_a1->seg_len)
+	      && compare_tree_int (dr_a1->seg_len, diff) <= 0)
+	    {
+	      dr_a1->seg_len = size_binop (PLUS_EXPR, dr_a2->seg_len,
+					   size_int (diff));
+	      do_remove = true;
+	    }
+	  /* Generally the new segment length is the maximum of the
+	     left segment size and the right segment size plus the distance.
+	     ???  We can also build tree MAX_EXPR here but it's not clear this
+	     is profitable.  */
+	  else if (tree_fits_uhwi_p (dr_a1->seg_len)
+		   && tree_fits_uhwi_p (dr_a2->seg_len))
+	    {
+	      unsigned HOST_WIDE_INT seg_len_a1 = tree_to_uhwi (dr_a1->seg_len);
+	      unsigned HOST_WIDE_INT seg_len_a2 = tree_to_uhwi (dr_a2->seg_len);
+	      dr_a1->seg_len = size_int (MAX (seg_len_a1, diff + seg_len_a2));
+	      do_remove = true;
+	    }
 	  /* Now we check if the following condition is satisfied:
 
 	     DIFF - SEGMENT_LENGTH_A < SEGMENT_LENGTH_B
@@ -3101,39 +3125,39 @@ vect_prune_runtime_alias_test_list (loop_vec_info loop_vinfo)
 	     one above:
 
 	     1: DIFF <= MIN_SEG_LEN_B
-	     2: DIFF - SEGMENT_LENGTH_A < MIN_SEG_LEN_B
-
-	     */
-
-	  unsigned HOST_WIDE_INT min_seg_len_b
-	    = (tree_fits_uhwi_p (dr_b1->seg_len)
-	       ? tree_to_uhwi (dr_b1->seg_len)
-	       : vect_factor);
+	     2: DIFF - SEGMENT_LENGTH_A < MIN_SEG_LEN_B  */
+	  else
+	    {
+	      unsigned HOST_WIDE_INT min_seg_len_b
+		= (tree_fits_uhwi_p (dr_b1->seg_len)
+		   ? tree_to_uhwi (dr_b1->seg_len)
+		   : vect_factor);
+
+	      if (diff <= min_seg_len_b
+		  || (tree_fits_uhwi_p (dr_a1->seg_len)
+		      && diff - tree_to_uhwi (dr_a1->seg_len) < min_seg_len_b))
+		{
+		  dr_a1->seg_len = size_binop (PLUS_EXPR,
+					       dr_a2->seg_len, size_int (diff));
+		  do_remove = true;
+		}
+	    }
 
-	  if (diff <= min_seg_len_b
-	      || (tree_fits_uhwi_p (dr_a1->seg_len)
-		  && diff - tree_to_uhwi (dr_a1->seg_len) < min_seg_len_b))
+	  if (do_remove)
 	    {
 	      if (dump_enabled_p ())
 		{
 		  dump_printf_loc (MSG_NOTE, vect_location,
 				   "merging ranges for ");
-		  dump_generic_expr (MSG_NOTE, TDF_SLIM,
-				     DR_REF (dr_a1->dr));
+		  dump_generic_expr (MSG_NOTE, TDF_SLIM, DR_REF (dr_a1->dr));
 		  dump_printf (MSG_NOTE,  ", ");
-		  dump_generic_expr (MSG_NOTE, TDF_SLIM,
-				     DR_REF (dr_b1->dr));
+		  dump_generic_expr (MSG_NOTE, TDF_SLIM, DR_REF (dr_b1->dr));
 		  dump_printf (MSG_NOTE,  " and ");
-		  dump_generic_expr (MSG_NOTE, TDF_SLIM,
-				     DR_REF (dr_a2->dr));
+		  dump_generic_expr (MSG_NOTE, TDF_SLIM, DR_REF (dr_a2->dr));
 		  dump_printf (MSG_NOTE,  ", ");
-		  dump_generic_expr (MSG_NOTE, TDF_SLIM,
-				     DR_REF (dr_b2->dr));
+		  dump_generic_expr (MSG_NOTE, TDF_SLIM, DR_REF (dr_b2->dr));
 		  dump_printf (MSG_NOTE, "\n");
 		}
-
-	      dr_a1->seg_len = size_binop (PLUS_EXPR,
-					   dr_a2->seg_len, size_int (diff));
 	      comp_alias_ddrs.ordered_remove (i--);
 	    }
 	}