Improve bitwise OR, AND ranges by using the same approximation we use for XOR.

runtime/vm/flow_graph_range_analysis.cc

Index: runtime/vm/flow_graph_range_analysis.cc
diff --git a/runtime/vm/flow_graph_range_analysis.cc b/runtime/vm/flow_graph_range_analysis.cc
index 0233d55abf1a335771fa45c4f55017888a3eee7b..e90a67ae7e166109ef44c1c8bc0685ea91c75e7d 100644
--- a/runtime/vm/flow_graph_range_analysis.cc
+++ b/runtime/vm/flow_graph_range_analysis.cc
@@ -2423,8 +2423,7 @@ void Range::And(const Range* left_range,
     return;
   }
 
-  *result_min = RangeBoundary::MinConstant(RangeBoundary::kRangeBoundaryInt64);
-  *result_max = RangeBoundary::MaxConstant(RangeBoundary::kRangeBoundaryInt64);
+  Xor(left_range, right_range, result_min, result_max);

[Florian Schneider, 2014/12/10 15:55:14]

Maybe this should be renamed to BitOp because the approximation is not specific
to xor.

 }
 
 
@@ -2631,8 +2630,8 @@ void Range::BinaryOp(const Token::Kind op,
       break;
 
     case Token::kBIT_OR:
-      *result = Range::Full(RangeBoundary::kRangeBoundaryInt64);
-      return;
+      Range::Xor(left_range, right_range, &min, &max);
+      break;
 
     default:
       *result = Range(RangeBoundary::NegativeInfinity(),