Codegen: track whether constant is accessed with pointerof(...)

src/compiler/crystal/codegen/types.cr

@@ -183,10 +183,14 @@ module Crystal
     # Returns `true` if this constant's value is a simple literal, like
     # `nil`, a number, char, string or symbol literal.
     def simple?
+      return false if pointer_read?
+
       value.simple_literal?
     end
 
     def needs_init_flag?
+      return true if pointer_read?
+
       !(initializer || no_init_flag? || simple?)
     end
 

src/compiler/crystal/semantic/main_visitor.cr

@@ -2559,6 +2559,7 @@ module Crystal
       when Path
         exp.accept self
         if const = exp.target_const
+          const.pointer_read = true
           const.value
         end
       when ReadInstanceVar

src/compiler/crystal/types.cr

@@ -3133,6 +3133,10 @@ module Crystal
     property vars : MetaVars?
     property? used = false
     property? visited = false
+
+    # Is this constant accessed with pointerof(...)?
+    property? pointer_read = false
+
     property visitor : MainVisitor?
 
     def initialize(program, namespace, name, @value)