[builtins] Introduce proper Float64Exp operator.

src/compiler/typer.cc

Index: src/compiler/typer.cc
diff --git a/src/compiler/typer.cc b/src/compiler/typer.cc
index 7caf16dff9499d80c5dcde6b7cba3fb0bd454a7e..7826e1703c7d809416a44170539aeca8967b511f 100644
--- a/src/compiler/typer.cc
+++ b/src/compiler/typer.cc
@@ -1543,9 +1543,10 @@ Type* Typer::Visitor::JSCallFunctionTyper(Type* fun, Typer* t) {
         case kMathTrunc:
           return t->cache_.kIntegerOrMinusZeroOrNaN;
         // Unary math functions.
+        case kMathExp:
+          return Type::Union(Type::PlainNumber(), Type::NaN(), t->zone());
         case kMathAbs:
         case kMathLog:
-        case kMathExp:
         case kMathSqrt:
         case kMathCos:
         case kMathSin:
@@ -1800,6 +1801,10 @@ Type* Typer::Visitor::TypeNumberAtan(Node* node) { return Type::Number(); }
 
 Type* Typer::Visitor::TypeNumberAtan2(Node* node) { return Type::Number(); }
 
+Type* Typer::Visitor::TypeNumberExp(Node* node) {
+  return Type::Union(Type::PlainNumber(), Type::NaN(), zone());
+}
+
 Type* Typer::Visitor::TypeNumberLog(Node* node) { return Type::Number(); }
 
 Type* Typer::Visitor::TypeNumberLog1p(Node* node) { return Type::Number(); }
@@ -2559,6 +2564,8 @@ Type* Typer::Visitor::TypeFloat64Atan(Node* node) { return Type::Number(); }
 
 Type* Typer::Visitor::TypeFloat64Atan2(Node* node) { return Type::Number(); }
 
+Type* Typer::Visitor::TypeFloat64Exp(Node* node) { return Type::Number(); }
+
 Type* Typer::Visitor::TypeFloat64Log(Node* node) { return Type::Number(); }
 
 Type* Typer::Visitor::TypeFloat64Log1p(Node* node) { return Type::Number(); }