Revert of [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 7826e1703c7d809416a44170539aeca8967b511f..7caf16dff9499d80c5dcde6b7cba3fb0bd454a7e 100644
--- a/src/compiler/typer.cc
+++ b/src/compiler/typer.cc
@@ -1543,10 +1543,9 @@
         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:
@@ -1801,10 +1800,6 @@
 
 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(); }
@@ -2564,8 +2559,6 @@
 
 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(); }