Better constant fold identity checks. (100 bytes saved on swarm, yeah! :))

lib/compiler/implementation/ssa/nodes.dart

 // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 interface HVisitor<R> {
   R visitAdd(HAdd node);
   R visitBitAnd(HBitAnd node);
   R visitBitNot(HBitNot node);
   R visitBitOr(HBitOr node);
   R visitBitXor(HBitXor node);
@@ skipping 856 matching lines @@
           inputUsedBy.removeLast();
           break;
         }
       }
     }
     this.block = null;
     assert(isValid());
   }
 
   bool isConstant() => false;
+  bool isConstantBoolean() => false;
   bool isConstantNull() => false;
   bool isConstantNumber() => false;
   bool isConstantString() => false;
   bool isConstantList() => false;
   bool isConstantMap() => false;
 
   bool isValid() {
     HValidator validator = new HValidator();
     validator.currentBlock = block;
     validator.visitInstruction(this);
@@ skipping 974 matching lines @@
   // TODO(1603): the class should be marked as abstract.
   abstract BinaryOperation get operation();
 }
 
 class HEquals extends HRelational {
   HEquals(HStatic target, HInstruction left, HInstruction right)
       : super(target, left, right);
   accept(HVisitor visitor) => visitor.visitEquals(this);
 
   bool get builtin() {
-    // All useful types have === semantics.
+    // All primitive types have === semantics.
     // Note that this includes all constants except the user-constructed
     // objects.
-    return left.isConstantNull() || left.propagatedType.isUseful();
+    return left.isConstantNull() || left.propagatedType.isPrimitive();
   }
 
   HType computeTypeFromInputTypes() {
     if (builtin) return HType.BOOLEAN;
     return HType.UNKNOWN;
   }
 
   HType computeDesiredTypeForNonTargetInput(HInstruction input) {
     if (input == left && right.propagatedType.isUseful()) {
       // All our useful types have === semantics. But we don't want to
@@ skipping 347 matching lines @@
   final bool isAnd;
   final SubExpression left;
   final SubExpression right;
   final HBasicBlock joinBlock;
   HAndOrBlockInformation(this.isAnd,
                          this.left,
                          this.right,
                          this.joinBlock);
   bool accept(HBlockInformationVisitor visitor) => visitor.visitAndOrInfo(this);
 }