For trigonometric functions call to C-libraries: they are faster than x87 operations (3% on Box2D).

runtime/vm/intermediate_language.h

 // Copyright (c) 2013, 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.
 
 #ifndef VM_INTERMEDIATE_LANGUAGE_H_
 #define VM_INTERMEDIATE_LANGUAGE_H_
 
 #include "vm/allocation.h"
 #include "vm/ast.h"
 #include "vm/growable_array.h"
@@ skipping 4642 matching lines @@
 
 class MathUnaryInstr : public TemplateDefinition<1> {
  public:
   MathUnaryInstr(MethodRecognizer::Kind kind, Value* value, intptr_t deopt_id)
       : kind_(kind) {
     SetInputAt(0, value);
     deopt_id_ = deopt_id;
   }
 
   Value* value() const { return inputs_[0]; }
-
   MethodRecognizer::Kind kind() const { return kind_; }
+  const RuntimeEntry& TargetFunction() const;
 
   virtual bool CanDeoptimize() const { return false; }
 
   virtual Representation representation() const {
     return kUnboxedDouble;
   }
 
   virtual Representation RequiredInputRepresentation(intptr_t idx) const {
     ASSERT(idx == 0);
     return kUnboxedDouble;
@@ skipping 2109 matching lines @@
   ForwardInstructionIterator* current_iterator_;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(FlowGraphVisitor);
 };
 
 
 }  // namespace dart
 
 #endif  // VM_INTERMEDIATE_LANGUAGE_H_