re PR tree-optimization/87022 (miscompilation with -ftree-loop-distribution)

	PR tree-optimization/87022
	* tree-loop-distribution.c (pg_add_dependence_edges): Check all
	bits in dist vector rather than the first one.
	
	gcc/testsuite
	PR tree-optimization/87022
	* gcc.dg/tree-ssa/pr87022.c: New test.

From-SVN: r265161

gcc/ChangeLog

+2018-10-15  Bin Cheng  <bin.cheng@linux.alibaba.com>
+
+	PR tree-optimization/87022
+	* tree-loop-distribution.c (pg_add_dependence_edges): Check all
+	bits in dist vector rather than the first one.
+
 2018-10-15  Richard Biener  <rguenther@suse.de>
 
 	PR middle-end/87610

gcc/testsuite/ChangeLog

+2018-10-15  Bin Cheng  <bin.cheng@linux.alibaba.com>
+
+	PR tree-optimization/87022
+	* gcc.dg/tree-ssa/pr87022.c: New test.
+
 2018-10-15  Richard Biener  <rguenther@suse.de>
 
 	PR middle-end/87610

gcc/testsuite/gcc.dg/tree-ssa/pr87022.c

+/* { dg-do run } */
+/* { dg-options "-O3" } */
+
+void abort();
+char a[7];
+char b[10][7];
+char r[10][7] = { {0,0,0,0,0,0,0},
+		  {0,0,0,0,0,0,0},
+		  {0,0,0,0,0,0,0},
+		  {0,0,0,0,0,0,0},
+		  {0,0,0,0,0,0,0},
+		  {0,0,0,0,0,0,0},
+		  {0,0,0,0,0,0,0},
+		  {0,0,1,1,1,1,1},
+		  {0,0,1,1,1,1,1},
+		  {0,0,1,1,1,1,1}};
+short c;
+int d, e, f, g;
+int main() {
+  for (; d <= 4; d++) {
+    e = 0;
+    for (; e <= 6; e++) {
+      if (a[c])
+        b[e + 3][d + 2] = 1;
+      a[0] = 5;
+      b[e][d + 2] = 0;
+    }
+  }
+  for (; f < 10; f++) {
+    g = 0;
+    for (; g < 7; g++)
+      if (b[f][g] != r[f][g])
+        abort ();
+  }
+  return 0;
+}

gcc/tree-loop-distribution.c

@@ -1921,7 +1921,8 @@ pg_add_dependence_edges (struct graph *rdg, int dir,
 	      if (DDR_NUM_DIST_VECTS (ddr) != 1)
 		this_dir = 2;
 	      /* If the overlap is exact preserve stmt order.  */
-	      else if (lambda_vector_zerop (DDR_DIST_VECT (ddr, 0), 1))
+	      else if (lambda_vector_zerop (DDR_DIST_VECT (ddr, 0),
+					    DDR_NB_LOOPS (ddr)))
 		;
 	      /* Else as the distance vector is lexicographic positive swap
 		 the dependence direction.  */