Misc range temporary fixes.

This fixes a couples places that were using int_range_max, but needed
a generic temporary.  Found while merging the frange work.

Also, copying between range temporaries is actually useful :).

Tested on x86-64 Linux.

gcc/ChangeLog:

	* gimple-range-cache.cc (ranger_cache::range_from_dom): Use
	Value_Range.
	* gimple-range.cc (gimple_ranger::register_inferred_ranges): Same.
	* value-range.h (Value_Range::Value_Range): Implement copy
	constructor for Value_Range.

gcc/gimple-range-cache.cc

@@ -1372,7 +1372,7 @@ ranger_cache::range_from_dom (vrange &r, tree name, basic_block start_bb,
 	      // each incoming edge now and accumulate the results.
 	      r.set_undefined ();
 	      edge_iterator ei;
-	      int_range_max er;
+	      Value_Range er (TREE_TYPE (name));
 	      FOR_EACH_EDGE (e, ei, prev_bb->preds)
 		{
 		  edge_range (er, e, name, RFD_READ_ONLY);

gcc/gimple-range.cc

@@ -461,17 +461,20 @@ gimple_ranger::register_inferred_ranges (gimple *s)
   tree lhs = gimple_get_lhs (s);
   if (lhs)
     {
-      int_range_max tmp;
+      Value_Range tmp (TREE_TYPE (lhs));
       if (range_of_stmt (tmp, s, lhs) && !tmp.varying_p ()
 	  && update_global_range (tmp, lhs) && dump_file)
 	{
-	  value_range vr = tmp;
+	  // ?? This section should be adjusted when non-iranges can
+	  // be exported.  For now, the only way update_global_range
+	  // above can succeed is with an irange so this is safe.
+	  value_range vr = as_a <irange> (tmp);
 	  fprintf (dump_file, "Global Exported: ");
 	  print_generic_expr (dump_file, lhs, TDF_SLIM);
 	  fprintf (dump_file, " = ");
 	  vr.dump (dump_file);
 	  int_range_max same = vr;
-	  if (same != tmp)
+	  if (same != as_a <irange> (tmp))
 	    {
 	      fprintf (dump_file, " ...  irange was : ");
 	      tmp.dump (dump_file);

gcc/value-range.h

@@ -314,6 +314,7 @@ class Value_Range
   Value_Range ();
   Value_Range (const vrange &r);
   Value_Range (tree type);
+  Value_Range (const Value_Range &);
   void set_type (tree type);
   vrange& operator= (const vrange &);
   bool operator== (const Value_Range &r) const;
@@ -344,7 +345,6 @@ class Value_Range
   unsupported_range m_unsupported;
   vrange *m_vrange;
   int_range_max m_irange;
-  DISABLE_COPY_AND_ASSIGN (Value_Range);
 };
 
 inline
@@ -370,6 +370,12 @@ Value_Range::Value_Range (tree type)
   init (type);
 }
 
+inline
+Value_Range::Value_Range (const Value_Range &r)
+{
+  m_vrange = r.m_vrange;
+}
+
 // Initialize object so it is possible to store temporaries of TYPE
 // into it.