Ensure consistent result of transcendental functions.

src/hydrogen-instructions.h

Index: src/hydrogen-instructions.h
diff --git a/src/hydrogen-instructions.h b/src/hydrogen-instructions.h
index eb0e0fd7d54e98f1ace426cf02a20c42f4e4b11d..a05fc776f848875e561e14e7c982229602b0134a 100644
--- a/src/hydrogen-instructions.h
+++ b/src/hydrogen-instructions.h
@@ -1886,6 +1886,7 @@ class HUnaryMathOperation: public HTemplateInstruction<2> {
       case kMathLog:
       case kMathSin:
       case kMathCos:
+      case kMathTan:
         set_representation(Representation::Double());
         break;
       default:
@@ -1916,6 +1917,7 @@ class HUnaryMathOperation: public HTemplateInstruction<2> {
         case kMathLog:
         case kMathSin:
         case kMathCos:
+        case kMathTan:
           return Representation::Double();
         case kMathAbs:
           return representation();