Add a fixed array type.

lib/compiler/implementation/ssa/optimize.dart

 // Copyright (c) 2012, 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.
 
 abstract class OptimizationPhase {
   String get name;
   void visitGraph(HGraph graph);
 }
 
 class SsaOptimizerTask extends CompilerTask {
@@ skipping 185 matching lines @@
       Constant folded = operation.fold(receiver.constant);
       if (folded !== null) return graph.addConstant(folded);
     }
     return node;
   }
 
   HInstruction visitInvokeInterceptor(HInvokeInterceptor node) {
     // Try to recognize the length interceptor with input [:new List(int):].
     if (node.isLengthGetter() && node.inputs[1] is HInvokeStatic) {
       HInvokeStatic call = node.inputs[1];
-      Element element = call.target.element;
-      if (element.isConstructor() &&
-          element.enclosingElement.declaration ==
-              compiler.listClass.defaultClass.element) {
-        if (call.inputs.length == 2 && call.inputs[1].isInteger(types)) {
-          return call.inputs[1];
-        }
+      if (isFixedSizeListConstructor(call)) {
+        return call.inputs[1];
       }
     }
     HInstruction input = node.inputs[1];
     if (node.isLengthGetter()) {
       if (input.isConstantString()) {
         HConstant constantInput = input;
         StringConstant constant = constantInput.constant;
         return graph.addConstantInt(constant.length, constantSystem);
       } else if (input.isConstantList()) {
         HConstant constantInput = input;
@@ skipping 21 matching lines @@
         transformToDynamicInvocation = false;
       }
       if (transformToDynamicInvocation) {
         return fromInterceptorToDynamicInvocation(node, node.selector);
       }
     }
 
     return node;
   }
 
+  bool isFixedSizeListConstructor(HInvokeStatic node) {
+    Element element = node.inputs[0].element;
+    return element.isConstructor()
+        && element.enclosingElement == compiler.listClass.defaultClass.element
+        && node.inputs.length == 2
+        && node.inputs[1].isInteger(types);
+  }
+
+  HInstruction visitInvokeStatic(HInvokeStatic node) {
+    if (isFixedSizeListConstructor(node)) {
+      node.guaranteedType = HType.FIXED_ARRAY;
+    }
+    return node;
+  }
+
   HInstruction visitInvokeDynamic(HInvokeDynamic node) {
     HType receiverType = types[node.receiver];
     if (receiverType.isExact()) {
       HBoundedType type = receiverType;
       Element element = type.lookupMember(node.selector.name);
       // TODO(ngeoffray): Also fold if it's a getter or variable.
       if (element != null && element.isFunction()) {
         if (node.selector.applies(element, compiler)) {
           FunctionElement method = element;
           FunctionSignature parameters = method.computeSignature(compiler);
@@ skipping 1059 matching lines @@
     }
 
     // For other fields having setters in the generative constructor body, set
     // the type to UNKNOWN to avoid relying on the type set in the initializer
     // list.
     allSetters.forEach((Element element) {
       backend.registerFieldConstructor(element, HType.UNKNOWN);
     });
   }
 }