union GTY ((ptr_alias (union lang_tree_node),
              desc ("tree_node_structure (&%h)"))) tree_node {
  struct tree_base GTY ((tag ("TS_BASE"))) base;
  struct tree_common GTY ((tag ("TS_COMMON"))) common;
  struct tree_int_cst GTY ((tag ("TS_INT_CST"))) int_cst;
  struct tree_real_cst GTY ((tag ("TS_REAL_CST"))) real_cst;
  struct tree_fixed_cst GTY ((tag ("TS_FIXED_CST"))) fixed_cst;
  struct tree_vector GTY ((tag ("TS_VECTOR"))) vector;
  struct tree_string GTY ((tag ("TS_STRING"))) string;
  struct tree_complex GTY ((tag ("TS_COMPLEX"))) complex;
  struct tree_identifier GTY ((tag ("TS_IDENTIFIER"))) identifier;
  struct tree_decl_minimal GTY((tag ("TS_DECL_MINIMAL"))) decl_minimal;
  struct tree_decl_common GTY ((tag ("TS_DECL_COMMON"))) decl_common;
  struct tree_decl_with_rtl GTY ((tag ("TS_DECL_WRTL"))) decl_with_rtl;
  struct tree_decl_non_common  GTY ((tag ("TS_DECL_NON_COMMON"))) decl_non_common;
  struct tree_parm_decl  GTY  ((tag ("TS_PARM_DECL"))) parm_decl;
  struct tree_decl_with_vis GTY ((tag ("TS_DECL_WITH_VIS"))) decl_with_vis;
  struct tree_var_decl GTY ((tag ("TS_VAR_DECL"))) var_decl;
  struct tree_field_decl GTY ((tag ("TS_FIELD_DECL"))) field_decl;
  struct tree_label_decl GTY ((tag ("TS_LABEL_DECL"))) label_decl;
  struct tree_result_decl GTY ((tag ("TS_RESULT_DECL"))) result_decl;
  struct tree_const_decl GTY ((tag ("TS_CONST_DECL"))) const_decl;
  struct tree_type_decl GTY ((tag ("TS_TYPE_DECL"))) type_decl;
  struct tree_function_decl GTY ((tag ("TS_FUNCTION_DECL"))) function_decl;
  struct tree_type GTY ((tag ("TS_TYPE"))) type;
  struct tree_list GTY ((tag ("TS_LIST"))) list;
  struct tree_vec GTY ((tag ("TS_VEC"))) vec;
  struct tree_exp GTY ((tag ("TS_EXP"))) exp;
  struct tree_ssa_name GTY ((tag ("TS_SSA_NAME"))) ssa_name;
  struct tree_block GTY ((tag ("TS_BLOCK"))) block;
  struct tree_binfo GTY ((tag ("TS_BINFO"))) binfo;
  struct tree_statement_list GTY ((tag ("TS_STATEMENT_LIST"))) stmt_list;
  struct tree_constructor GTY ((tag ("TS_CONSTRUCTOR"))) constructor;
  struct tree_omp_clause GTY ((tag ("TS_OMP_CLAUSE"))) omp_clause;
  struct tree_optimization_option GTY ((tag ("TS_OPTIMIZATION"))) optimization;
  struct tree_target_option GTY ((tag ("TS_TARGET_OPTION"))) target_option;
};