Revert r16032: it revealed a bug in our bailout environment computation.

sdk/lib/_internal/compiler/implementation/ssa/bailout.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.
 
 part of ssa;
 
 class BailoutInfo {
   int instructionId;
   int bailoutId;
   BailoutInfo(this.instructionId, this.bailoutId);
@@ skipping 121 matching lines @@
       return false;
     }
 
     // If the instruction is not in a loop then the header will be null.
     HBasicBlock currentLoopHeader = instruction.block.enclosingLoopHeader;
     for (HInstruction user in instruction.usedBy) {
       HBasicBlock userLoopHeader = user.block.enclosingLoopHeader;
       if (isNested(userLoopHeader, currentLoopHeader)) return true;
     }
 
-    bool isIndexOperatorOnIndexablePrimitive(instruction, types) {
-      return instruction is HIndex
-          || (instruction is HInvokeDynamicMethod
-              && instruction.isIndexOperatorOnIndexablePrimitive(types));
-    }
-
     // To speed up computations on values loaded from arrays, we
     // insert type guards for builtin array indexing operations in
     // nested loops. Since this can blow up code size quite
     // significantly, we only do it if type guards have already been
     // inserted for this method. The code size price for an additional
     // type guard is much smaller than the first one that causes the
     // generation of a bailout method.
-    if (hasTypeGuards
-        && isIndexOperatorOnIndexablePrimitive(instruction, types)) {
+    if (instruction is HIndex &&
+        (instruction as HIndex).isBuiltin(types) &&
+        hasTypeGuards) {
       HBasicBlock loopHeader = instruction.block.enclosingLoopHeader;
       if (loopHeader != null && loopHeader.parentLoopHeader != null) {
         return true;
       }
     }
 
     // If the instruction is used by a phi where a guard would be
     // valuable, put the guard on that instruction.
     for (HInstruction user in instruction.usedBy) {
       if (user is HPhi
@@ skipping 377 matching lines @@
         hasComplexBailoutTargets = true;
       }
     } else {
       hasComplexBailoutTargets = true;
       blocks.forEach((HBasicBlock block) {
         block.bailoutTargets.add(target);
       });
     }
   }
 }