re PR tree-optimization/41956 (Segfault in vectorizer)

	PR tree-optimization/41956
	* tree-vect-slp.c (vect_supported_load_permutation_p): Add check that 
	the load indices differ.

From-SVN: r155523

gcc/ChangeLog

+2009-12-30  Ira Rosen  <irar@il.ibm.com>
+
+	PR tree-optimization/41956
+	* tree-vect-slp.c (vect_supported_load_permutation_p): Add check that 
+	the load indices differ.
+
 2009-12-30  Uros Bizjak  <ubizjak@gmail.com>
 
 	PR target/42549

gcc/testsuite/ChangeLog

+2009-12-30  Ira Rosen  <irar@il.ibm.com>
+
+	PR tree-optimization/41956
+	* gcc.dg/vect/pr41956.c: New test.
+
 2009-12-30  Uros Bizjak  <ubizjak@gmail.com>
 
 	PR target/42549

gcc/testsuite/gcc.dg/vect/pr41956.c

+/* { dg-do compile } */
+/* { dg-require-effective-target vect_int } */
+
+void K (int *gpwgts, int *badminpwgt, int *badmaxpwgt)
+{
+  int i;
+  for (i = 0; i < 10; i += 2) {
+    badminpwgt[i] = badminpwgt[i+1] = gpwgts[i]+gpwgts[i];
+    badmaxpwgt[i] = badmaxpwgt[i+1] = gpwgts[i]+gpwgts[i];
+  }
+}
+
+/* { dg-final { cleanup-tree-dump "vect" } } */

gcc/tree-vect-slp.c

@@ -796,6 +796,7 @@ vect_supported_load_permutation_p (slp_instance slp_instn, int group_size,
 {
   int i = 0, j, prev = -1, next, k;
   bool supported;
+  sbitmap load_index;
 
   /* FORNOW: permutations are only supported in SLP.  */
   if (!slp_instn)
@@ -816,6 +817,8 @@ vect_supported_load_permutation_p (slp_instance slp_instn, int group_size,
     return false;
 
   supported = true;
+  load_index = sbitmap_alloc (group_size);
+  sbitmap_zero (load_index);
   for (j = 0; j < group_size; j++)
     {
       for (i = j * group_size, k = 0;
@@ -830,7 +833,17 @@ vect_supported_load_permutation_p (slp_instance slp_instn, int group_size,
 
          prev = next;
        }
+
+      if (TEST_BIT (load_index, prev))
+        {
+          supported = false;
+          break;
+        }
+
+      SET_BIT (load_index, prev);
     }
+  
+  sbitmap_free (load_index);
 
   if (supported && i == group_size * group_size
       && vect_supported_slp_permutation_p (slp_instn))