[backport from gcc-4.7.1 r187770 <mikpe@it.uu.se>]

gcc/

2012-05-22  Richard Guenther  <rguenther@suse.de>

	PR tree-optimization/53408
	* tree-vect-loop.c (vectorizable_induction): Properly check
	the restriction that we cannot handle induction results from
	the inner loop outside of the outer loop.

gcc/testsuite/

2012-05-22  Richard Guenther  <rguenther@suse.de>

	PR tree-optimization/53408
	* gcc.dg/torture/pr53408.c: New testcase.

--- gcc-4.6.3/gcc/testsuite/gcc.dg/torture/pr53408.c.~1~	1970-01-01 01:00:00.000000000 +0100
+++ gcc-4.6.3/gcc/testsuite/gcc.dg/torture/pr53408.c	2012-06-09 22:42:56.000000000 +0200
@@ -0,0 +1,20 @@
+/* { dg-do compile } */
+
+int a, b, c, d, e;
+void
+fn1 ()
+{
+  int f, g;
+  char h = 0;
+  b = 0;
+  for (; b < 32; b++)
+    {
+      g = h > e ? h : h << 1;
+      f = g && a ? 0 : 1;
+      h = 1;
+      for (; h > 0; h = h + 1)
+	c = 0 < h | f;
+    }
+  if (h)
+    d = 0;
+}
--- gcc-4.6.3/gcc/tree-vect-loop.c.~1~	2011-06-04 11:20:00.000000000 +0200
+++ gcc-4.6.3/gcc/tree-vect-loop.c	2012-06-09 22:42:56.000000000 +0200
@@ -4545,12 +4545,46 @@ vectorizable_induction (gimple phi, gimp
   tree vec_def;
 
   gcc_assert (ncopies >= 1);
-  /* FORNOW. This restriction should be relaxed.  */
-  if (nested_in_vect_loop_p (loop, phi) && ncopies > 1)
+  /* FORNOW. These restrictions should be relaxed.  */
+  if (nested_in_vect_loop_p (loop, phi))
     {
-      if (vect_print_dump_info (REPORT_DETAILS))
-        fprintf (vect_dump, "multiple types in nested loop.");
-      return false;
+      imm_use_iterator imm_iter;
+      use_operand_p use_p;
+      gimple exit_phi;
+      edge latch_e;
+      tree loop_arg;
+
+      if (ncopies > 1)
+	{
+	  if (vect_print_dump_info (REPORT_DETAILS))
+	    fprintf (vect_dump, "multiple types in nested loop.");
+	  return false;
+	}
+
+      exit_phi = NULL;
+      latch_e = loop_latch_edge (loop->inner);
+      loop_arg = PHI_ARG_DEF_FROM_EDGE (phi, latch_e);
+      FOR_EACH_IMM_USE_FAST (use_p, imm_iter, loop_arg)
+	{
+	  if (!flow_bb_inside_loop_p (loop->inner,
+				      gimple_bb (USE_STMT (use_p))))
+	    {
+	      exit_phi = USE_STMT (use_p);
+	      break;
+	    }
+	}
+      if (exit_phi)
+	{
+	  stmt_vec_info exit_phi_vinfo  = vinfo_for_stmt (exit_phi);
+	  if (!(STMT_VINFO_RELEVANT_P (exit_phi_vinfo)
+		&& !STMT_VINFO_LIVE_P (exit_phi_vinfo)))
+	    {
+	      if (vect_print_dump_info (REPORT_DETAILS))
+		fprintf (vect_dump, "inner-loop induction only used outside "
+			 "of the outer vectorized loop.");
+	      return false;
+	    }
+	}
     }
 
   if (!STMT_VINFO_RELEVANT_P (stmt_info))