Use simple loop tracking instead of size to determine if

lib/compiler/implementation/ssa/codegen.dart

Index: lib/compiler/implementation/ssa/codegen.dart
diff --git a/lib/compiler/implementation/ssa/codegen.dart b/lib/compiler/implementation/ssa/codegen.dart
index 1b7e7d16c32cdbe58adca3905b604347a719b59a..67d4934fb3a59407466d634b6e7e31e19e86492b 100644
--- a/lib/compiler/implementation/ssa/codegen.dart
+++ b/lib/compiler/implementation/ssa/codegen.dart
@@ -1585,13 +1585,17 @@ class SsaCodeGenerator implements HVisitor, HBlockInformationVisitor {
       buffer.add(compiler.namer.instanceMethodInvocationName(
           currentLibrary, node.name, node.selector));
       visitArguments(node.inputs);
+      var inLoop = node.block.enclosingLoopHeader !== null;
       if (node.element !== null) {
         // If we know we're calling a specific method, register that
         // method only.
+        if (inLoop) node.element.calledInLoop = true;
         world.registerDynamicInvocationOf(node.element);
       } else {
         world.registerDynamicInvocation(
-            node.name, getOptimizedSelectorFor(node, node.selector));
+            node.name,
+            getOptimizedSelectorFor(node, node.selector),
+            inLoop: inLoop);
       }
     }
     endExpression(JSPrecedence.CALL_PRECEDENCE);
@@ -2623,12 +2627,12 @@ class SsaUnoptimizedCodeGenerator extends SsaCodeGenerator {
   // find the name of its checked input. Note that there must be a
   // name, otherwise the instruction would not be in the live
   // environment.
-  HInstruction unwrap(argument) {	
+  HInstruction unwrap(argument) {
     while (argument is HCheck && !variableNames.hasName(argument)) {
       argument = argument.checkedInput;
     }
     assert(variableNames.hasName(argument));
-    return argument;	
+    return argument;
   }
 
   void visitTypeGuard(HTypeGuard node) {