[builtins] Introduce proper Float64Tan operator.

src/compiler/js-builtin-reducer.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/compiler/js-builtin-reducer.h"
 #include "src/compiler/js-graph.h"
 #include "src/compiler/node-matchers.h"
 #include "src/compiler/node-properties.h"
 #include "src/compiler/simplified-operator.h"
 #include "src/objects-inl.h"
@@ skipping 356 matching lines @@
   JSCallReduction r(node);
   if (r.InputsMatchOne(Type::PlainPrimitive())) {
     // Math.sqrt(a:plain-primitive) -> NumberSqrt(ToNumber(a))
     Node* input = ToNumber(r.GetJSCallInput(0));
     Node* value = graph()->NewNode(simplified()->NumberSqrt(), input);
     return Replace(value);
   }
   return NoChange();
 }
 
+// ES6 section 20.2.2.33 Math.tan ( x )
+Reduction JSBuiltinReducer::ReduceMathTan(Node* node) {
+  JSCallReduction r(node);
+  if (r.InputsMatchOne(Type::PlainPrimitive())) {
+    // Math.tan(a:plain-primitive) -> NumberTan(ToNumber(a))
+    Node* input = ToNumber(r.GetJSCallInput(0));
+    Node* value = graph()->NewNode(simplified()->NumberTan(), input);
+    return Replace(value);
+  }
+  return NoChange();
+}
+
 // ES6 section 20.2.2.35 Math.trunc ( x )
 Reduction JSBuiltinReducer::ReduceMathTrunc(Node* node) {
   JSCallReduction r(node);
   if (r.InputsMatchOne(Type::PlainPrimitive())) {
     // Math.trunc(a:plain-primitive) -> NumberTrunc(ToNumber(a))
     Node* input = ToNumber(r.GetJSCallInput(0));
     Node* value = graph()->NewNode(simplified()->NumberTrunc(), input);
     return Replace(value);
   }
   return NoChange();
@@ skipping 74 matching lines @@
       break;
     case kMathRound:
       reduction = ReduceMathRound(node);
       break;
     case kMathSin:
       reduction = ReduceMathSin(node);
       break;
     case kMathSqrt:
       reduction = ReduceMathSqrt(node);
       break;
+    case kMathTan:
+      reduction = ReduceMathTan(node);
+      break;
     case kMathTrunc:
       reduction = ReduceMathTrunc(node);
       break;
     case kStringFromCharCode:
       reduction = ReduceStringFromCharCode(node);
       break;
     default:
       break;
   }
 
@@ skipping 28 matching lines @@
 }
 
 
 SimplifiedOperatorBuilder* JSBuiltinReducer::simplified() const {
   return jsgraph()->simplified();
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8