tr: Remove the concept of 'higher type'.

A higher type was set in a few places, but not used otherwise.

ir/lower/lower_calls.c

@@ -199,8 +199,6 @@ static ir_type *lower_mtp(lowering_env_t const *const env, ir_type *mtp)
 	for (size_t i = 0; i < nn_ress; ++i)
 		set_method_res_type(lowered, i, results[i]);
 
-	/* associate the lowered type with the original one for easier access */
-	set_higher_type(lowered, mtp);
 	pmap_insert(lowered_mtps, mtp, lowered);
 
 	return lowered;

ir/lower/lower_dw.c

@@ -1625,7 +1625,6 @@ static ir_type *lower_mtp(ir_type *mtp)
 		set_method_res_type(res, n_res++, tp);
 	}
 
-	set_higher_type(res, mtp);
 	set_type_link(res, mtp);
 
 	mark_type_visited(res);

ir/lower/lower_softfloat.c

@@ -356,8 +356,6 @@ static ir_type *lower_method_type(ir_type *mtp)
 		set_method_res_type(res, i, rtp);
 	}
 
-	set_higher_type(res, mtp);
-
 	pmap_insert(lowered_type, mtp, res);
 	return res;
 }

ir/tr/type.c

@@ -547,7 +547,6 @@ ir_type *clone_type_method(ir_type *const tp, bool const is_variadic, mtp_additi
 	set_type_dbg_info(res, db);
 
 	res->flags                        = tp->flags;
-	res->higher_type                  = tp->higher_type;
 	res->size                         = tp->size;
 	res->attr.method.n_params         = n_params;
 	res->attr.method.params           = XMALLOCN(ir_type*, n_params);

ir/tr/type_t.h

@@ -86,12 +86,11 @@ typedef struct {
 typedef enum type_flags {
 	tf_none          = 0,       /**< No flags. */
 	tf_compound      = 1U << 0, /**< Set if type is a compound type. */
-	tf_lowered_type  = 1U << 1, /**< Set if this is a lowered type. */
-	tf_layout_fixed  = 1U << 2, /**< Set if the layout of a type is fixed */
+	tf_layout_fixed  = 1U << 1, /**< Set if the layout of a type is fixed */
 
-	tf_frame_type    = 1U << 3, /**< Set if this is a frame type. */
-	tf_info          = 1U << 4, /**< infos (for example constructor, destructor pointers), all members are anonymous */
-	tf_lowered_dw    = 1U << 5, /**< hack to identify lowered doubleword params */
+	tf_frame_type    = 1U << 2, /**< Set if this is a frame type. */
+	tf_info          = 1U << 3, /**< infos (for example constructor, destructor pointers), all members are anonymous */
+	tf_lowered_dw    = 1U << 4, /**< hack to identify lowered doubleword params */
 } type_flags;
 ENUM_BITSET(type_flags)
 
@@ -126,8 +125,6 @@ struct ir_type {
 	ir_visited_t visit;      /**< visited counter for walks of the type information */
 	void *link;              /**< holds temporary data - like in irnode_t.h */
 	type_dbg_info *dbi;      /**< A pointer to information for debug support. */
-	ir_type *higher_type;    /**< link to highlevel type in case of lowered
-	                              types */
 	long nr;                 /**< An unique number for each type. */
 	union {
 		compound_attr compound;
@@ -170,22 +167,6 @@ static inline ir_visited_t get_master_type_visited_(void)
 	return firm_type_visited;
 }
 
-static inline int is_lowered_type(const ir_type *tp)
-{
-	return tp->flags & tf_lowered_type;
-}
-
-static inline ir_type *get_higher_type(const ir_type *tp)
-{
-	return tp->higher_type;
-}
-
-static inline void set_higher_type(ir_type *tp, ir_type *higher_type)
-{
-	tp->flags |= tf_lowered_type;
-	tp->higher_type = higher_type;
-}
-
 static inline void *get_type_link_(const ir_type *tp)
 {
 	assert(tp->kind == k_type);