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

runtime/vm/intermediate_language.cc

 // 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.
 
 #include "vm/intermediate_language.h"
 
 #include "vm/bigint_operations.h"
 #include "vm/bit_vector.h"
 #include "vm/dart_entry.h"
 #include "vm/flow_graph_allocator.h"
@@ skipping 2623 matching lines @@
       return kPowRuntimeEntry;
     case MethodRecognizer::kDoubleMod:
       return kModRuntimeEntry;
     default:
       UNREACHABLE();
   }
   return kPowRuntimeEntry;
 }
 
 
+extern const RuntimeEntry kCosRuntimeEntry(
+    "libc_cos", reinterpret_cast<RuntimeFunction>(
+        static_cast<UnaryMathCFunction>(&cos)), 1, true, true);
+
+extern const RuntimeEntry kSinRuntimeEntry(
+    "libc_sin", reinterpret_cast<RuntimeFunction>(
+        static_cast<UnaryMathCFunction>(&sin)), 1, true, true);
+
+
+const RuntimeEntry& MathUnaryInstr::TargetFunction() const {
+  switch (kind()) {
+    case MethodRecognizer::kMathSin:
+      return kSinRuntimeEntry;
+    case MethodRecognizer::kMathCos:
+      return kCosRuntimeEntry;
+    default:
+      UNREACHABLE();
+  }
+  return kSinRuntimeEntry;
+}
+
 #undef __
 
 }  // namespace dart