Revert "[turbofan] Weakening of types must weaken ranges inside unions."

src/compiler/typer.cc

Index: src/compiler/typer.cc
diff --git a/src/compiler/typer.cc b/src/compiler/typer.cc
index 20a39d94493ff1eed1463e1a142d7cd037c90655..97b43f4aefb989ac69e732a14c3fa77b954920a9 100644
--- a/src/compiler/typer.cc
+++ b/src/compiler/typer.cc
@@ -1119,9 +1119,10 @@ Bounds Typer::Visitor::TypeJSLoadNamed(Node* node) {
 // in the graph. In the current implementation, we are
 // increasing the limits to the closest power of two.
 Type* Typer::Visitor::Weaken(Type* current_type, Type* previous_type) {
-  Type::RangeType* previous = previous_type->GetRange();
-  Type::RangeType* current = current_type->GetRange();
-  if (previous != NULL && current != NULL) {
+  if (current_type->IsRange() && previous_type->IsRange()) {
+    Type::RangeType* previous = previous_type->AsRange();
+    Type::RangeType* current = current_type->AsRange();
+
     double current_min = current->Min()->Number();
     Handle<Object> new_min = current->Min();
 
@@ -1151,9 +1152,7 @@ Type* Typer::Visitor::Weaken(Type* current_type, Type* previous_type) {
       }
     }
 
-    return Type::Union(current_type,
-                       Type::Range(new_min, new_max, typer_->zone()),
-                       typer_->zone());
+    return Type::Range(new_min, new_max, typer_->zone());
   }
   return current_type;
 }