[017/236] Add subclasses for the various kinds of instruction

diff --git a/gcc/coretypes.h b/gcc/coretypes.h
index f22b980..17dc0e6 100644
--- a/gcc/coretypes.h
+++ b/gcc/coretypes.h
@@ -57,10 +57,19 @@  typedef struct rtx_def *rtx;
 typedef const struct rtx_def *const_rtx;
 
 /* Subclasses of rtx_def, using indentation to show the class
-   hierarchy.
+   hierarchy, along with the relevant invariant.
    Where possible, keep this list in the same order as in rtl.def.  */
 class rtx_def;
   class rtx_insn;
+    class rtx_real_insn;         /* INSN_P (X) */
+      class rtx_debug_insn;      /* DEBUG_INSN_P (X) */
+      class rtx_nonjump_insn;    /* NONJUMP_INSN_P (X) */
+      class rtx_jump_insn;       /* JUMP_P (X) */
+      class rtx_call_insn;       /* CALL_P (X) */
+    class rtx_jump_table_data;   /* JUMP_TABLE_DATA_P (X) */
+    class rtx_barrier;           /* BARRIER_P (X) */
+    class rtx_code_label;        /* LABEL_P (X) */
+    class rtx_note;              /* NOTE_P (X) */
 
 struct rtvec_def;
 typedef struct rtvec_def *rtvec;
diff --git a/gcc/rtl.h b/gcc/rtl.h
index 5936829..31df60f 100644
--- a/gcc/rtl.h
+++ b/gcc/rtl.h
@@ -421,6 +421,110 @@  class GTY(()) rtx_insn : public rtx_def
   */
 };
 
+class GTY(()) rtx_real_insn : public rtx_insn
+{
+  /* No extra fields, but adds the invariant:
+       INSN_P (X)
+     i.e. that we have a "real" insn, one of:
+       (NONJUMP_INSN_P (X) || DEBUG_INSN_P (X) || JUMP_P (X) || CALL_P (X))
+  */
+};
+
+/* Subclasses of rtx_real_insn.  */
+
+class GTY(()) rtx_debug_insn : public rtx_real_insn
+{
+  /* No extra fields, but adds the invariant:
+       DEBUG_INSN_P (X) aka (GET_CODE (X) == DEBUG_INSN)
+     i.e. an annotation for tracking variable assignments.
+
+     This is an instance of:
+       DEF_RTL_EXPR(DEBUG_INSN, "debug_insn", "uuBeiie", RTX_INSN)
+     from rtl.def.  */
+};
+
+class GTY(()) rtx_nonjump_insn : public rtx_real_insn
+{
+  /* No extra fields, but adds the invariant:
+       NONJUMP_INSN_P (X) aka (GET_CODE (X) == INSN)
+     i.e an instruction that cannot jump.
+
+     This is an instance of:
+       DEF_RTL_EXPR(INSN, "insn", "uuBeiie", RTX_INSN)
+     from rtl.def.  */
+};
+
+class GTY(()) rtx_jump_insn : public rtx_real_insn
+{
+  /* No extra fields, but adds the invariant:
+       JUMP_P (X) aka (GET_CODE (X) == JUMP_INSN)
+     i.e. an instruction that can possibly jump.
+
+     This is an instance of:
+       DEF_RTL_EXPR(JUMP_INSN, "jump_insn", "uuBeiie0", RTX_INSN)
+     from rtl.def.  */
+};
+
+class GTY(()) rtx_call_insn : public rtx_real_insn
+{
+  /* No extra fields, but adds the invariant:
+       CALL_P (X) aka (GET_CODE (X) == CALL_INSN)
+     i.e. an instruction that can possibly call a subroutine
+     but which will not change which instruction comes next
+     in the current function.
+
+     This is an instance of:
+       DEF_RTL_EXPR(CALL_INSN, "call_insn", "uuBeiiee", RTX_INSN)
+     from rtl.def.  */
+};
+
+/* Subclasses of rtx_insn not derived from rtx_real_insn.  */
+
+class GTY(()) rtx_jump_table_data : public rtx_insn
+{
+  /* No extra fields, but adds the invariant:
+       JUMP_TABLE_DATA_P (X) aka (GET_CODE (INSN) == JUMP_TABLE_DATA)
+     i.e. a data for a jump table, considered an instruction for
+     historical reasons.
+
+     This is an instance of:
+       DEF_RTL_EXPR(JUMP_TABLE_DATA, "jump_table_data", "uuBe0000", RTX_INSN)
+     from rtl.def.  */
+};
+
+class GTY(()) rtx_barrier : public rtx_insn
+{
+  /* No extra fields, but adds the invariant:
+       BARRIER_P (X) aka (GET_CODE (X) == BARRIER)
+     i.e. a marker that indicates that control will not flow through.
+
+     This is an instance of:
+       DEF_RTL_EXPR(BARRIER, "barrier", "uu00000", RTX_EXTRA)
+     from rtl.def.  */
+};
+
+class GTY(()) rtx_code_label : public rtx_insn
+{
+  /* No extra fields, but adds the invariant:
+       LABEL_P (X) aka (GET_CODE (X) == CODE_LABEL)
+     i.e. a label in the assembler.
+
+     This is an instance of:
+       DEF_RTL_EXPR(CODE_LABEL, "code_label", "uuB00is", RTX_EXTRA)
+     from rtl.def.  */
+};
+
+class GTY(()) rtx_note : public rtx_insn
+{
+  /* No extra fields, but adds the invariant:
+       NOTE_P(X) aka (GET_CODE (X) == NOTE)
+     i.e. a note about the corresponding source code.
+
+     This is an instance of:
+       DEF_RTL_EXPR(NOTE, "note", "uuB0ni", RTX_EXTRA)
+     from rtl.def.  */
+};
+
 /* The size in bytes of an rtx header (code, mode and flags).  */
 #define RTX_HDR_SIZE offsetof (struct rtx_def, u)
 
@@ -606,6 +710,102 @@  is_a_helper <const rtx_insn *>::test (const_rtx rt)
 	  || LABEL_P (rt));
 }
 
+template <>
+template <>
+inline bool
+is_a_helper <rtx_real_insn *>::test (rtx rt)
+{
+  return INSN_P (rt);
+}
+
+template <>
+template <>
+inline bool
+is_a_helper <rtx_debug_insn *>::test (rtx rt)
+{
+  return DEBUG_INSN_P (rt);
+}
+
+template <>
+template <>
+inline bool
+is_a_helper <rtx_nonjump_insn *>::test (rtx rt)
+{
+  return NONJUMP_INSN_P (rt);
+}
+
+template <>
+template <>
+inline bool
+is_a_helper <rtx_jump_insn *>::test (rtx rt)
+{
+  return JUMP_P (rt);
+}
+
+template <>
+template <>
+inline bool
+is_a_helper <rtx_call_insn *>::test (rtx rt)
+{
+  return CALL_P (rt);
+}
+
+template <>
+template <>
+inline bool
+is_a_helper <rtx_jump_table_data *>::test (rtx rt)
+{
+  return JUMP_TABLE_DATA_P (rt);
+}
+
+template <>
+template <>
+inline bool
+is_a_helper <rtx_jump_table_data *>::test (rtx_insn *insn)
+{
+  return JUMP_TABLE_DATA_P (insn);
+}
+
+template <>
+template <>
+inline bool
+is_a_helper <rtx_barrier *>::test (rtx rt)
+{
+  return BARRIER_P (rt);
+}
+
+template <>
+template <>
+inline bool
+is_a_helper <rtx_code_label *>::test (rtx rt)
+{
+  return LABEL_P (rt);
+}
+
+template <>
+template <>
+inline bool
+is_a_helper <rtx_code_label *>::test (rtx_insn *insn)
+{
+  return LABEL_P (insn);
+}
+
+template <>
+template <>
+inline bool
+is_a_helper <rtx_note *>::test (rtx rt)
+{
+  return NOTE_P (rt);
+}
+
+template <>
+template <>
+inline bool
+is_a_helper <rtx_note *>::test (rtx_insn *insn)
+{
+  return NOTE_P (insn);
+}
+
 /* Predicate yielding nonzero iff X is a return or simple_return.  */
 #define ANY_RETURN_P(X) \
   (GET_CODE (X) == RETURN || GET_CODE (X) == SIMPLE_RETURN)