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

runtime/vm/intermediate_language_mips.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/globals.h"  // Needed here to get TARGET_ARCH_MIPS.
 #if defined(TARGET_ARCH_MIPS)
 
 #include "vm/intermediate_language.h"
 
 #include "vm/dart_entry.h"
@@ skipping 3166 matching lines @@
   return NULL;
 }
 
 
 void BinaryUint32x4OpInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
   UNIMPLEMENTED();
 }
 
 
 LocationSummary* MathUnaryInstr::MakeLocationSummary() const {
+  if ((kind() == MethodRecognizer::kMathSin) ||
+      (kind() == MethodRecognizer::kMathCos)) {
+    const intptr_t kNumInputs = 1;
+    const intptr_t kNumTemps = 0;
+    LocationSummary* summary =
+        new LocationSummary(kNumInputs, kNumTemps, LocationSummary::kCall);
+    summary->set_in(0, Location::FpuRegisterLocation(D6));
+    summary->set_out(Location::FpuRegisterLocation(D0));
+    return summary;
+  }
   const intptr_t kNumInputs = 1;
   const intptr_t kNumTemps = 0;
   LocationSummary* summary =
       new LocationSummary(kNumInputs, kNumTemps, LocationSummary::kNoCall);
   summary->set_in(0, Location::RequiresFpuRegister());
   summary->set_out(Location::RequiresFpuRegister());
   return summary;
 }
 
 
 void MathUnaryInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
   if (kind() == MethodRecognizer::kMathSqrt) {
     __ sqrtd(locs()->out().fpu_reg(), locs()->in(0).fpu_reg());
   } else {
-    UNIMPLEMENTED();
+    __ CallRuntime(TargetFunction(), InputCount());
   }
 }
 
 
 LocationSummary* MathMinMaxInstr::MakeLocationSummary() const {
   if (result_cid() == kDoubleCid) {
     const intptr_t kNumInputs = 2;
     const intptr_t kNumTemps = 1;
     LocationSummary* summary =
         new LocationSummary(kNumInputs, kNumTemps, LocationSummary::kNoCall);
@@ skipping 853 matching lines @@
   compiler->GenerateCall(token_pos(),
                          &label,
                          PcDescriptors::kOther,
                          locs());
   __ Drop(2);  // Discard type arguments and receiver.
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_MIPS