[turbofan] Added the RoundInt64ToFloat64 instruction to TurboFan.

src/compiler/typer.cc

Index: src/compiler/typer.cc
diff --git a/src/compiler/typer.cc b/src/compiler/typer.cc
index ea20cec83fdbfd2c8a26c483b28c2634e82c63c4..dcdf0241eefaeca5a5755f8e64671ecdd40d2f08 100644
--- a/src/compiler/typer.cc
+++ b/src/compiler/typer.cc
@@ -1994,6 +1994,11 @@ Type* Typer::Visitor::TypeChangeInt32ToFloat64(Node* node) {
 }
 
 
+Type* Typer::Visitor::TypeRoundInt64ToFloat64(Node* node) {
+  return Type::Intersect(Type::Internal(), Type::UntaggedFloat64(), zone());

[rossberg, 2015/11/03 10:46:32]

This gives the return type, so should be Number, not Internal. (Can this ever
result in NaN or -0? If not, you can actually make it PlainNumber.)

[ahaas, 2015/11/03 15:03:38]

Done.

+}
+
+
 Type* Typer::Visitor::TypeChangeInt32ToInt64(Node* node) {
   return Type::Internal();
 }