Use JavaScript runtime semantics when constant folding.

lib/compiler/implementation/ssa/builder.dart

Index: lib/compiler/implementation/ssa/builder.dart
diff --git a/lib/compiler/implementation/ssa/builder.dart b/lib/compiler/implementation/ssa/builder.dart
index 01149a64e0d5b9d5001d68794c98d6cc4d49d3dd..473def66ff819d5558c07989a9dd8da32df9523b 100644
--- a/lib/compiler/implementation/ssa/builder.dart
+++ b/lib/compiler/implementation/ssa/builder.dart
@@ -153,7 +153,9 @@ class SsaBuilderTask extends CompilerTask {
     return measure(() {
       FunctionElement element = work.element;
       HInstruction.idCounter = 0;
-      SsaBuilder builder = new SsaBuilder(this, work);
+      FoldingOperations foldingOperations =
+          compiler.constantHandler.foldingOperations;
+      SsaBuilder builder = new SsaBuilder(foldingOperations, this, work);
       HGraph graph;
       ElementKind kind = element.kind;
       if (kind === ElementKind.GENERATIVE_CONSTRUCTOR) {
@@ -797,6 +799,7 @@ class SsaBuilder extends ResolvedVisitor implements Visitor {
   final SsaBuilderTask builder;
   final Interceptors interceptors;
   final WorkItem work;
+  final FoldingOperations foldingOperations;
   bool methodInterceptionEnabled;
   HGraph graph;
   LocalsHandler localsHandler;
@@ -827,7 +830,7 @@ class SsaBuilder extends ResolvedVisitor implements Visitor {
   Compiler get compiler() => builder.compiler;
   CodeEmitterTask get emitter() => builder.emitter;
 
-  SsaBuilder(SsaBuilderTask builder, WorkItem work)
+  SsaBuilder(this.foldingOperations, SsaBuilderTask builder, WorkItem work)
     : this.builder = builder,
       this.work = work,
       interceptors = builder.interceptors,
@@ -1639,7 +1642,8 @@ class SsaBuilder extends ResolvedVisitor implements Visitor {
     // See if we can constant-fold right away. This avoids rewrites later on.
     if (operand is HConstant) {
       HConstant constant = operand;
-      Constant folded = result.operation.fold(constant.constant);
+      Constant folded =
+          result.operation(foldingOperations).fold(constant.constant);
       if (folded !== null) {
         stack.add(graph.addConstant(folded));
         return;