re PR tree-optimization/51301 (Compiler ICE in vect_is_simple_use_1)

        PR tree-optimization/51301
        * tree-vect-patterns.c (vect_recog_over_widening_pattern): Check
        that the last statement doesn't convert to a bigger type than the
        original type of the computation.

From-SVN: r181797

gcc/ChangeLog

+2011-11-29  Ira Rosen  <ira.rosen@linaro.org>
+
+	PR tree-optimization/51301
+	* tree-vect-patterns.c (vect_recog_over_widening_pattern): Check that
+	the last statement doesn't convert to a bigger type than the original
+	type of the computation.
+
 2011-11-28  Richard Henderson  <rth@redhat.com>
 
 	* config/rs6000/rs6000.c (rs6000_expand_atomic_compare_and_swap):

gcc/testsuite/ChangeLog

+2011-11-29  Ira Rosen  <ira.rosen@linaro.org>
+
+	PR tree-optimization/51301
+	* gcc.dg/vect/pr51301.c: New test.
+
 2011-11-28  Uros Bizjak  <ubizjak@gmail.com>
 
 	* g++.dg/cdce3.C: Use dg-additional-options.

gcc/testsuite/gcc.dg/vect/pr51301.c

+/* { dg-do compile } */
+
+typedef signed char int8_t;
+typedef signed long long int64_t;
+int64_t
+f0a (int8_t * __restrict__ arg1)
+{
+  int idx;
+  int64_t result = 0;
+  for (idx = 0; idx < 416; idx += 1)
+    result += arg1[idx] << (arg1[idx] == arg1[idx]);
+  return result;
+}
+
+/* { dg-final { cleanup-tree-dump "vect" } } */

gcc/tree-vect-patterns.c

@@ -1088,6 +1088,7 @@ vect_recog_over_widening_pattern (VEC (gimple, heap) **stmts,
   tree var = NULL_TREE, new_type = NULL_TREE, tmp, new_oprnd;
   bool first;
   struct loop *loop = (gimple_bb (stmt))->loop_father;
+  tree type = NULL;
 
   first = true;
   while (1)
@@ -1150,6 +1151,7 @@ vect_recog_over_widening_pattern (VEC (gimple, heap) **stmts,
           print_gimple_stmt (vect_dump, pattern_stmt, 0, TDF_SLIM);
         }
 
+      type = gimple_expr_type (stmt);
       prev_stmt = stmt;
       stmt = use_stmt;
 
@@ -1165,9 +1167,11 @@ vect_recog_over_widening_pattern (VEC (gimple, heap) **stmts,
     {
       use_lhs = gimple_assign_lhs (use_stmt);
       use_type = TREE_TYPE (use_lhs);
-      /* Support only type promotion or signedess change.  */
+      /* Support only type promotion or signedess change.  Check that USE_TYPE
+	 is not bigger than the original type.  */
       if (!INTEGRAL_TYPE_P (use_type)
-          || TYPE_PRECISION (new_type) > TYPE_PRECISION (use_type))
+          || TYPE_PRECISION (new_type) > TYPE_PRECISION (use_type)
+	  || TYPE_PRECISION (type) < TYPE_PRECISION (use_type))
         return NULL;
 
       if (TYPE_UNSIGNED (new_type) != TYPE_UNSIGNED (use_type)