VM: Support fast calls to atan and atan2 in optimized code.

runtime/vm/flow_graph_optimizer.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/flow_graph_optimizer.h"
 
 #include "vm/bit_vector.h"
 #include "vm/cha.h"
 #include "vm/compiler.h"
 #include "vm/cpu.h"
@@ skipping 4545 matching lines @@
                       call->env(),
                       call);
         AddCheckClass(min_max->right()->definition(),
                       unary_checks,
                       call->deopt_id(),
                       call->env(),
                       call);
         ReplaceCall(call, min_max);
       }
     }
-  } else if (recognized_kind == MethodRecognizer::kMathDoublePow) {
+  } else if ((recognized_kind == MethodRecognizer::kMathDoublePow) ||
+             (recognized_kind == MethodRecognizer::kMathAtan) ||
+             (recognized_kind == MethodRecognizer::kMathAtan2)) {
     if (FLAG_precompilation) {
       // No UnboxDouble instructons allowed.
       return;
     }
     // We know that first argument is double, the second is num.

[Vyacheslav Egorov (Google), 2016/02/04 10:30:58]

The comment is a bit confusing now because it does not apply to either atan
(it's a single argument function) or atan2 (it has two arguments but *both* are
num).

[Florian Schneider, 2016/02/04 21:41:49]

Done.

     // InvokeMathCFunctionInstr requires unboxed doubles. UnboxDouble
     // instructions contain type checks and conversions to double.
     ZoneGrowableArray<Value*>* args =
         new(Z) ZoneGrowableArray<Value*>(call->ArgumentCount());
     for (intptr_t i = 0; i < call->ArgumentCount(); i++) {
       args->Add(new(Z) Value(call->ArgumentAt(i)));
     }
     InvokeMathCFunctionInstr* invoke =
         new(Z) InvokeMathCFunctionInstr(args,
                                         call->deopt_id(),
@@ skipping 4265 matching lines @@
 
   // Insert materializations at environment uses.
   for (intptr_t i = 0; i < exits_collector_.exits().length(); i++) {
     CreateMaterializationAt(
         exits_collector_.exits()[i], alloc, *slots);
   }
 }
 
 
 }  // namespace dart