Fix PR42640: Correctly initialize the value of the new induction variable.

2010-03-02  Reza Yazdani  <reza.yazdani@amd.com>

	PR middle-end/42640
	* tree-loop-distribution.c (update_phis_for_loop_copy): Replaced
	the assignment from the new induction variable to the assignment
	of the value from the original loop PHI function.

	* gcc.dg/tree-ssa/pr42640.c: New.

From-SVN: r157161

gcc/ChangeLog

+2010-03-02  Reza Yazdani  <reza.yazdani@amd.com>
+
+	PR middle-end/42640
+	* tree-loop-distribution.c (update_phis_for_loop_copy): Replaced
+	the assignment from the new induction variable to the assignment
+	of the value from the original loop PHI function.
+
 2010-03-01  Janis Johnson  <janis187@us.ibm.com>
 	    Daniel Jacobowitz  <dan@codesourcery.com>
 

gcc/testsuite/ChangeLog

+2010-03-02  Reza Yazdani  <reza.yazdani@amd.com>
+
+	PR middle-end/42640
+	* gcc.dg/tree-ssa/pr42640.c: New.
+
 2010-03-01  Richard Guenther  <rguenther@suse.de>
 
 	PR tree-optimization/43220

gcc/testsuite/gcc.dg/tree-ssa/pr42640.c

+/* { dg-do run } */
+/* { dg-options "-O2 -ftree-loop-distribution" } */
+
+/* Checks if loop distribution works correctly if the subscript used
+   is assigned to a loop invariant value.  */
+
+extern void abort (void);
+struct S { int a; int b; int c; };
+
+int get_rr_node_index (int i)
+{
+  return i;
+}
+
+struct S nodes[8];
+struct S *rr_node = nodes;
+volatile int io_rat = 2;
+void
+doit (int i, int j)
+{
+  int s_node, p_node, inode, ipad, iloop;
+
+  for (ipad = 0; ipad < io_rat; ipad++)
+    {
+      p_node = get_rr_node_index (ipad+2);
+      inode = get_rr_node_index (ipad);
+
+      for (iloop = 1; iloop <= 2; iloop++)
+	{
+	  rr_node[inode].a = i;
+	  rr_node[inode].b = j;
+	  rr_node[inode].c = ipad;
+	  inode = p_node;
+	}
+    }
+}
+
+int
+main ()
+{
+  int i;
+
+  doit (1, 2);
+
+  if (rr_node[0].a != rr_node[1].a
+      || rr_node[2].a != rr_node[3].a
+      || rr_node[1].a != 1
+      || rr_node[0].b != rr_node[1].b
+      || rr_node[2].b != rr_node[3].b
+      || rr_node[1].b != 2
+      || rr_node[0].c != 0
+      || rr_node[1].c != 1
+      || rr_node[2].c != 0
+      || rr_node[3].c != 1)
+    abort ();
+
+  return 0;
+}

gcc/tree-loop-distribution.c

@@ -118,8 +118,8 @@ update_phis_for_loop_copy (struct loop *orig_loop, struct loop *new_loop)
 
 	  if (!new_ssa_name)
 	    /* This only happens if there are no definitions inside the
-	       loop.  Use the phi_result in this case.  */
-	    new_ssa_name = PHI_RESULT (phi_new);
+	       loop.  Use the the invariant in the new loop as is.  */
+	    new_ssa_name = def;
 	}
       else
 	/* Could be an integer.  */