diff mbox series

[C,1/6] c: reorganize recursive type checking

Message ID 1df29de95ff41a02ffd218f4cd69f8f93df35321.camel@tugraz.at
State New
Headers show
Series [C,1/6] c: reorganize recursive type checking | expand

Commit Message

Martin Uecker Aug. 26, 2023, 4:20 p.m. UTC
Reorganize recursive type checking to use a structure to
store information collected during the recursion and
returned to the caller (warning_needed, enum_and_init_p,
different_types_p).

gcc/c:
	* c-typeck.cc (struct comptypes_data): Add structure.
	(tagged_types_tu_compatible_p,
	function_types_compatible_p, type_lists_compatible_p,
	comptypes_internal): Add structure to interface, change
	return type to bool, and adapt calls.
	(comptarget_types): Change return type too bool.
	(comptypes, comptypes_check_enum_int,
	comptypes_check_different_types): Adapt calls.
---
 gcc/c/c-typeck.cc | 266 ++++++++++++++++++++--------------------------
 1 file changed, 114 insertions(+), 152 deletions(-)

Comments

Joseph Myers Sept. 6, 2023, 8:59 p.m. UTC | #1
On Sat, 26 Aug 2023, Martin Uecker via Gcc-patches wrote:

> -static int
> +static bool
>  comp_target_types (location_t location, tree ttl, tree ttr)

The comment above this function should be updated to refer to returning 
true, not to returning 1.  And other comments on common_pointer_type and 
inside that function should be updated to refer to comp_target_types 
returning true, not nonzero.

> @@ -1395,17 +1382,13 @@ free_all_tagged_tu_seen_up_to (const struct tagged_tu_seen_cache *tu_til)
>  
>  /* Return 1 if two 'struct', 'union', or 'enum' types T1 and T2 are
>     compatible.  If the two types are not the same (which has been
> -   checked earlier), this can only happen when multiple translation
> -   units are being compiled.  See C99 6.2.7 paragraph 1 for the exact
> -   rules.  ENUM_AND_INT_P and DIFFERENT_TYPES_P are as in
> -   comptypes_internal.  */
> +   checked earlier).  */
>  
> -static int
> +static bool
>  tagged_types_tu_compatible_p (const_tree t1, const_tree t2,
> -			      bool *enum_and_int_p, bool *different_types_p)
> +			      struct comptypes_data* data)

Similarly, this comment should be updated for the new return type.  Also 
the GNU style is "struct comptypes_data *data" with space before not after 
'*'.

> @@ -1631,9 +1603,9 @@ tagged_types_tu_compatible_p (const_tree t1, const_tree t2,
>     Otherwise, the argument types must match.
>     ENUM_AND_INT_P and DIFFERENT_TYPES_P are as in comptypes_internal.  */
>  
> -static int
> +static bool
>  function_types_compatible_p (const_tree f1, const_tree f2,
> -			     bool *enum_and_int_p, bool *different_types_p)
> +			     struct comptypes_data *data)

Another comment to update for a changed return type.

>  /* Check two lists of types for compatibility, returning 0 for
> -   incompatible, 1 for compatible, or 2 for compatible with
> -   warning.  ENUM_AND_INT_P and DIFFERENT_TYPES_P are as in
> -   comptypes_internal.  */
> +   incompatible, 1 for compatible.  ENUM_AND_INT_P and
> +   DIFFERENT_TYPES_P are as in comptypes_internal.  */
>  
> -static int
> +static bool
>  type_lists_compatible_p (const_tree args1, const_tree args2,
> -			 bool *enum_and_int_p, bool *different_types_p)
> +			 struct comptypes_data *data)

This one also needs updating to remove references to parameters that no 
longer exist.
diff mbox series

Patch

diff --git a/gcc/c/c-typeck.cc b/gcc/c/c-typeck.cc
index e6ddf37d412..ed1520ed6ba 100644
--- a/gcc/c/c-typeck.cc
+++ b/gcc/c/c-typeck.cc
@@ -90,12 +90,14 @@  static bool require_constant_elements;
 static bool require_constexpr_value;
 
 static tree qualify_type (tree, tree);
-static int tagged_types_tu_compatible_p (const_tree, const_tree, bool *,
-					 bool *);
-static int comp_target_types (location_t, tree, tree);
-static int function_types_compatible_p (const_tree, const_tree, bool *,
-					bool *);
-static int type_lists_compatible_p (const_tree, const_tree, bool *, bool *);
+struct comptypes_data;
+static bool tagged_types_tu_compatible_p (const_tree, const_tree,
+					  struct comptypes_data *);
+static bool comp_target_types (location_t, tree, tree);
+static bool function_types_compatible_p (const_tree, const_tree,
+					 struct comptypes_data *);
+static bool type_lists_compatible_p (const_tree, const_tree,
+				     struct comptypes_data *);
 static tree lookup_field (tree, tree);
 static int convert_arguments (location_t, vec<location_t>, tree,
 			      vec<tree, va_gc> *, vec<tree, va_gc> *, tree,
@@ -125,7 +127,8 @@  static tree find_init_member (tree, struct obstack *);
 static void readonly_warning (tree, enum lvalue_use);
 static int lvalue_or_else (location_t, const_tree, enum lvalue_use);
 static void record_maybe_used_decl (tree);
-static int comptypes_internal (const_tree, const_tree, bool *, bool *);
+static bool comptypes_internal (const_tree, const_tree,
+				struct comptypes_data *data);
 
 /* Return true if EXP is a null pointer constant, false otherwise.  */
 
@@ -1039,6 +1042,13 @@  common_type (tree t1, tree t2)
   return c_common_type (t1, t2);
 }
 
+struct comptypes_data {
+
+  bool enum_and_int_p;
+  bool different_types_p;
+  bool warning_needed;
+};
+
 /* Return 1 if TYPE1 and TYPE2 are compatible types for assignment
    or various other operations.  Return 2 if they are compatible
    but a warning may be needed if you use them together.  */
@@ -1047,12 +1057,13 @@  int
 comptypes (tree type1, tree type2)
 {
   const struct tagged_tu_seen_cache * tagged_tu_seen_base1 = tagged_tu_seen_base;
-  int val;
 
-  val = comptypes_internal (type1, type2, NULL, NULL);
+  struct comptypes_data data = { };
+  bool ret = comptypes_internal (type1, type2, &data);
+
   free_all_tagged_tu_seen_up_to (tagged_tu_seen_base1);
 
-  return val;
+  return ret ? (data.warning_needed ? 2 : 1) : 0;
 }
 
 /* Like comptypes, but if it returns non-zero because enum and int are
@@ -1062,12 +1073,14 @@  int
 comptypes_check_enum_int (tree type1, tree type2, bool *enum_and_int_p)
 {
   const struct tagged_tu_seen_cache * tagged_tu_seen_base1 = tagged_tu_seen_base;
-  int val;
 
-  val = comptypes_internal (type1, type2, enum_and_int_p, NULL);
+  struct comptypes_data data = { };
+  bool ret = comptypes_internal (type1, type2, &data);
+  *enum_and_int_p = data.enum_and_int_p;
+
   free_all_tagged_tu_seen_up_to (tagged_tu_seen_base1);
 
-  return val;
+  return ret ? (data.warning_needed ? 2 : 1) : 0;
 }
 
 /* Like comptypes, but if it returns nonzero for different types, it
@@ -1078,40 +1091,40 @@  comptypes_check_different_types (tree type1, tree type2,
 				 bool *different_types_p)
 {
   const struct tagged_tu_seen_cache * tagged_tu_seen_base1 = tagged_tu_seen_base;
-  int val;
 
-  val = comptypes_internal (type1, type2, NULL, different_types_p);
+  struct comptypes_data data = { };
+  bool ret = comptypes_internal (type1, type2, &data);
+  *different_types_p = data.different_types_p;
+
   free_all_tagged_tu_seen_up_to (tagged_tu_seen_base1);
 
-  return val;
+  return ret ? (data.warning_needed ? 2 : 1) : 0;
 }
 
-/* Return 1 if TYPE1 and TYPE2 are compatible types for assignment
-   or various other operations.  Return 2 if they are compatible
-   but a warning may be needed if you use them together.  If
-   ENUM_AND_INT_P is not NULL, and one type is an enum and the other a
-   compatible integer type, then this sets *ENUM_AND_INT_P to true;
-   *ENUM_AND_INT_P is never set to false.  If DIFFERENT_TYPES_P is not
-   NULL, and the types are compatible but different enough not to be
+/* Return true if TYPE1 and TYPE2 are compatible types for assignment
+   or various other operations.  If they are compatible but a warning may
+   be needed if you use them together, 'warning_needed' in DATA is set.
+   If one type is an enum and the other a compatible integer type, then
+   this sets 'enum_and_int_p' in DATA to true (it is never set to
+   false).  If the types are compatible but different enough not to be
    permitted in C11 typedef redeclarations, then this sets
-   *DIFFERENT_TYPES_P to true; *DIFFERENT_TYPES_P is never set to
+   'different_types_p' in DATA to true; it is never set to
    false, but may or may not be set if the types are incompatible.
    This differs from comptypes, in that we don't free the seen
    types.  */
 
-static int
-comptypes_internal (const_tree type1, const_tree type2, bool *enum_and_int_p,
-		    bool *different_types_p)
+static bool
+comptypes_internal (const_tree type1, const_tree type2,
+		    struct comptypes_data *data)
 {
   const_tree t1 = type1;
   const_tree t2 = type2;
-  int attrval, val;
 
   /* Suppress errors caused by previously reported errors.  */
 
   if (t1 == t2 || !t1 || !t2
       || TREE_CODE (t1) == ERROR_MARK || TREE_CODE (t2) == ERROR_MARK)
-    return 1;
+    return true;
 
   /* Enumerated types are compatible with integer types, but this is
      not transitive: two enumerated types in the same translation unit
@@ -1124,10 +1137,8 @@  comptypes_internal (const_tree type1, const_tree type2, bool *enum_and_int_p,
       t1 = ENUM_UNDERLYING_TYPE (t1);
       if (TREE_CODE (t2) != VOID_TYPE)
 	{
-	  if (enum_and_int_p != NULL)
-	    *enum_and_int_p = true;
-	  if (different_types_p != NULL)
-	    *different_types_p = true;
+	  data->enum_and_int_p = true;
+	  data->different_types_p = true;
 	}
     }
   else if (TREE_CODE (t2) == ENUMERAL_TYPE
@@ -1137,25 +1148,23 @@  comptypes_internal (const_tree type1, const_tree type2, bool *enum_and_int_p,
       t2 = ENUM_UNDERLYING_TYPE (t2);
       if (TREE_CODE (t1) != VOID_TYPE)
 	{
-	  if (enum_and_int_p != NULL)
-	    *enum_and_int_p = true;
-	  if (different_types_p != NULL)
-	    *different_types_p = true;
+	  data->enum_and_int_p = true;
+	  data->different_types_p = true;
 	}
     }
 
   if (t1 == t2)
-    return 1;
+    return true;
 
   /* Different classes of types can't be compatible.  */
 
   if (TREE_CODE (t1) != TREE_CODE (t2))
-    return 0;
+    return false;
 
   /* Qualifiers must match. C99 6.7.3p9 */
 
   if (TYPE_QUALS (t1) != TYPE_QUALS (t2))
-    return 0;
+    return false;
 
   /* Allow for two different type nodes which have essentially the same
      definition.  Note that we already checked for equality of the type
@@ -1163,14 +1172,16 @@  comptypes_internal (const_tree type1, const_tree type2, bool *enum_and_int_p,
 
   if (TREE_CODE (t1) != ARRAY_TYPE
       && TYPE_MAIN_VARIANT (t1) == TYPE_MAIN_VARIANT (t2))
-    return 1;
+    return true;
+
+  int attrval;
 
   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
   if (!(attrval = comp_type_attributes (t1, t2)))
-     return 0;
+     return false;
 
-  /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
-  val = 0;
+  if (2 == attrval)
+    data->warning_needed = true;
 
   switch (TREE_CODE (t1))
     {
@@ -1196,16 +1207,11 @@  comptypes_internal (const_tree type1, const_tree type2, bool *enum_and_int_p,
     case POINTER_TYPE:
       /* Do not remove mode information.  */
       if (TYPE_MODE (t1) != TYPE_MODE (t2))
-	break;
-      val = (TREE_TYPE (t1) == TREE_TYPE (t2)
-	     ? 1 : comptypes_internal (TREE_TYPE (t1), TREE_TYPE (t2),
-				       enum_and_int_p, different_types_p));
-      break;
+	return false;
+      return comptypes_internal (TREE_TYPE (t1), TREE_TYPE (t2), data);
 
     case FUNCTION_TYPE:
-      val = function_types_compatible_p (t1, t2, enum_and_int_p,
-					 different_types_p);
-      break;
+      return function_types_compatible_p (t1, t2, data);
 
     case ARRAY_TYPE:
       {
@@ -1213,21 +1219,16 @@  comptypes_internal (const_tree type1, const_tree type2, bool *enum_and_int_p,
 	tree d2 = TYPE_DOMAIN (t2);
 	bool d1_variable, d2_variable;
 	bool d1_zero, d2_zero;
-	val = 1;
 
 	/* Target types must match incl. qualifiers.  */
-	if (TREE_TYPE (t1) != TREE_TYPE (t2)
-	    && (val = comptypes_internal (TREE_TYPE (t1), TREE_TYPE (t2),
-					  enum_and_int_p,
-					  different_types_p)) == 0)
-	  return 0;
-
-	if (different_types_p != NULL
-	    && (d1 == NULL_TREE) != (d2 == NULL_TREE))
-	  *different_types_p = true;
+	if (!comptypes_internal (TREE_TYPE (t1), TREE_TYPE (t2), data))
+	  return false;
+
+	if ((d1 == NULL_TREE) != (d2 == NULL_TREE))
+	  data->different_types_p = true;
 	/* Sizes must match unless one is missing or variable.  */
 	if (d1 == NULL_TREE || d2 == NULL_TREE || d1 == d2)
-	  break;
+	  return true;
 
 	d1_zero = !TYPE_MAX_VALUE (d1);
 	d2_zero = !TYPE_MAX_VALUE (d2);
@@ -1241,51 +1242,37 @@  comptypes_internal (const_tree type1, const_tree type2, bool *enum_and_int_p,
 	d1_variable = d1_variable || (d1_zero && C_TYPE_VARIABLE_SIZE (t1));
 	d2_variable = d2_variable || (d2_zero && C_TYPE_VARIABLE_SIZE (t2));
 
-	if (different_types_p != NULL
-	    && d1_variable != d2_variable)
-	  *different_types_p = true;
+	if (d1_variable != d2_variable)
+	  data->different_types_p = true;
 	if (d1_variable || d2_variable)
-	  break;
+	  return true;
 	if (d1_zero && d2_zero)
-	  break;
+	  return true;
 	if (d1_zero || d2_zero
 	    || !tree_int_cst_equal (TYPE_MIN_VALUE (d1), TYPE_MIN_VALUE (d2))
 	    || !tree_int_cst_equal (TYPE_MAX_VALUE (d1), TYPE_MAX_VALUE (d2)))
-	  val = 0;
+	  return false;
 
-	break;
+	return true;
       }
 
     case ENUMERAL_TYPE:
     case RECORD_TYPE:
     case UNION_TYPE:
-      if (val != 1 && false)
+      if (false)
 	{
-	  tree a1 = TYPE_ATTRIBUTES (t1);
-	  tree a2 = TYPE_ATTRIBUTES (t2);
-
-	  if (! attribute_list_contained (a1, a2)
-	      && ! attribute_list_contained (a2, a1))
-	    break;
-
-	  val = tagged_types_tu_compatible_p (t1, t2, enum_and_int_p,
-					      different_types_p);
-
-	  if (attrval != 2)
-	    return val;
+	  return tagged_types_tu_compatible_p (t1, t2, data);
 	}
-      break;
+      return false;
 
     case VECTOR_TYPE:
-      val = (known_eq (TYPE_VECTOR_SUBPARTS (t1), TYPE_VECTOR_SUBPARTS (t2))
-	     && comptypes_internal (TREE_TYPE (t1), TREE_TYPE (t2),
-				    enum_and_int_p, different_types_p));
-      break;
+      return known_eq (TYPE_VECTOR_SUBPARTS (t1), TYPE_VECTOR_SUBPARTS (t2))
+	     && comptypes_internal (TREE_TYPE (t1), TREE_TYPE (t2), data);
 
     default:
-      break;
+      return false;
     }
-  return attrval == 2 && val == 1 ? 2 : val;
+  gcc_unreachable ();
 }
 
 /* Return 1 if TTL and TTR are pointers to types that are equivalent, ignoring
@@ -1293,7 +1280,7 @@  comptypes_internal (const_tree type1, const_tree type2, bool *enum_and_int_p,
    different named addresses, then we must determine if one address space is a
    subset of the other.  */
 
-static int
+static bool
 comp_target_types (location_t location, tree ttl, tree ttr)
 {
   int val;
@@ -1395,17 +1382,13 @@  free_all_tagged_tu_seen_up_to (const struct tagged_tu_seen_cache *tu_til)
 
 /* Return 1 if two 'struct', 'union', or 'enum' types T1 and T2 are
    compatible.  If the two types are not the same (which has been
-   checked earlier), this can only happen when multiple translation
-   units are being compiled.  See C99 6.2.7 paragraph 1 for the exact
-   rules.  ENUM_AND_INT_P and DIFFERENT_TYPES_P are as in
-   comptypes_internal.  */
+   checked earlier).  */
 
-static int
+static bool
 tagged_types_tu_compatible_p (const_tree t1, const_tree t2,
-			      bool *enum_and_int_p, bool *different_types_p)
+			      struct comptypes_data* data)
 {
   tree s1, s2;
-  bool needs_warning = false;
 
   /* We have to verify that the tags of the types are the same.  This
      is harder than it looks because this may be a typedef, so we have
@@ -1513,8 +1496,7 @@  tagged_types_tu_compatible_p (const_tree t1, const_tree t2,
 
 	    if (DECL_NAME (s1) != DECL_NAME (s2))
 	      break;
-	    result = comptypes_internal (TREE_TYPE (s1), TREE_TYPE (s2),
-					 enum_and_int_p, different_types_p);
+	    result = comptypes_internal (TREE_TYPE (s1), TREE_TYPE (s2), data);
 
 	    if (result != 1 && !DECL_NAME (s1))
 	      break;
@@ -1523,8 +1505,6 @@  tagged_types_tu_compatible_p (const_tree t1, const_tree t2,
 		tu->val = 0;
 		return 0;
 	      }
-	    if (result == 2)
-	      needs_warning = true;
 
 	    if (TREE_CODE (s1) == FIELD_DECL
 		&& simple_cst_equal (DECL_FIELD_BIT_OFFSET (s1),
@@ -1536,7 +1516,6 @@  tagged_types_tu_compatible_p (const_tree t1, const_tree t2,
 	  }
 	if (!s1 && !s2)
 	  {
-	    tu->val = needs_warning ? 2 : 1;
 	    return tu->val;
 	  }
 
@@ -1550,8 +1529,7 @@  tagged_types_tu_compatible_p (const_tree t1, const_tree t2,
 		  int result;
 
 		  result = comptypes_internal (TREE_TYPE (s1), TREE_TYPE (s2),
-					       enum_and_int_p,
-					       different_types_p);
+					       data);
 
 		  if (result != 1 && !DECL_NAME (s1))
 		    continue;
@@ -1560,8 +1538,6 @@  tagged_types_tu_compatible_p (const_tree t1, const_tree t2,
 		      tu->val = 0;
 		      return 0;
 		    }
-		  if (result == 2)
-		    needs_warning = true;
 
 		  if (TREE_CODE (s1) == FIELD_DECL
 		      && simple_cst_equal (DECL_FIELD_BIT_OFFSET (s1),
@@ -1577,7 +1553,6 @@  tagged_types_tu_compatible_p (const_tree t1, const_tree t2,
 		return 0;
 	      }
 	  }
-	tu->val = needs_warning ? 2 : 1;
 	return tu->val;
       }
 
@@ -1599,12 +1574,9 @@  tagged_types_tu_compatible_p (const_tree t1, const_tree t2,
 	    if (TREE_CODE (s1) != TREE_CODE (s2)
 		|| DECL_NAME (s1) != DECL_NAME (s2))
 	      break;
-	    result = comptypes_internal (TREE_TYPE (s1), TREE_TYPE (s2),
-					 enum_and_int_p, different_types_p);
+	    result = comptypes_internal (TREE_TYPE (s1), TREE_TYPE (s2), data);
 	    if (result == 0)
 	      break;
-	    if (result == 2)
-	      needs_warning = true;
 
 	    if (TREE_CODE (s1) == FIELD_DECL
 		&& simple_cst_equal (DECL_FIELD_BIT_OFFSET (s1),
@@ -1614,7 +1586,7 @@  tagged_types_tu_compatible_p (const_tree t1, const_tree t2,
 	if (s1 && s2)
 	  tu->val = 0;
 	else
-	  tu->val = needs_warning ? 2 : 1;
+	  tu->val = 1;
 	return tu->val;
       }
 
@@ -1631,9 +1603,9 @@  tagged_types_tu_compatible_p (const_tree t1, const_tree t2,
    Otherwise, the argument types must match.
    ENUM_AND_INT_P and DIFFERENT_TYPES_P are as in comptypes_internal.  */
 
-static int
+static bool
 function_types_compatible_p (const_tree f1, const_tree f2,
-			     bool *enum_and_int_p, bool *different_types_p)
+			     struct comptypes_data *data)
 {
   tree args1, args2;
   /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
@@ -1654,16 +1626,15 @@  function_types_compatible_p (const_tree f1, const_tree f2,
   if (TYPE_VOLATILE (ret2))
     ret2 = build_qualified_type (TYPE_MAIN_VARIANT (ret2),
 				 TYPE_QUALS (ret2) & ~TYPE_QUAL_VOLATILE);
-  val = comptypes_internal (ret1, ret2, enum_and_int_p, different_types_p);
+  val = comptypes_internal (ret1, ret2, data);
   if (val == 0)
     return 0;
 
   args1 = TYPE_ARG_TYPES (f1);
   args2 = TYPE_ARG_TYPES (f2);
 
-  if (different_types_p != NULL
-      && (args1 == NULL_TREE) != (args2 == NULL_TREE))
-    *different_types_p = true;
+  if ((args1 == NULL_TREE) != (args2 == NULL_TREE))
+    data->different_types_p = true;
 
   /* An unspecified parmlist matches any specified parmlist
      whose argument types don't need default promotions.  */
@@ -1679,8 +1650,11 @@  function_types_compatible_p (const_tree f1, const_tree f2,
 	 If they don't match, ask for a warning (but no error).  */
       if (TYPE_ACTUAL_ARG_TYPES (f1)
 	  && type_lists_compatible_p (args2, TYPE_ACTUAL_ARG_TYPES (f1),
-				      enum_and_int_p, different_types_p) != 1)
-	val = 2;
+				      data) != 1)
+	{
+	  val = 1;
+	  data->warning_needed = true;
+	}
       return val;
     }
   if (args2 == NULL_TREE)
@@ -1691,35 +1665,32 @@  function_types_compatible_p (const_tree f1, const_tree f2,
 	return 0;
       if (TYPE_ACTUAL_ARG_TYPES (f2)
 	  && type_lists_compatible_p (args1, TYPE_ACTUAL_ARG_TYPES (f2),
-				      enum_and_int_p, different_types_p) != 1)
-	val = 2;
+				      data) != 1)
+	{
+	  val = 1;
+	  data->warning_needed = true;
+	}
       return val;
     }
 
   /* Both types have argument lists: compare them and propagate results.  */
-  val1 = type_lists_compatible_p (args1, args2, enum_and_int_p,
-				  different_types_p);
-  return val1 != 1 ? val1 : val;
+  val1 = type_lists_compatible_p (args1, args2, data);
+  return val1;
 }
 
 /* Check two lists of types for compatibility, returning 0 for
-   incompatible, 1 for compatible, or 2 for compatible with
-   warning.  ENUM_AND_INT_P and DIFFERENT_TYPES_P are as in
-   comptypes_internal.  */
+   incompatible, 1 for compatible.  ENUM_AND_INT_P and
+   DIFFERENT_TYPES_P are as in comptypes_internal.  */
 
-static int
+static bool
 type_lists_compatible_p (const_tree args1, const_tree args2,
-			 bool *enum_and_int_p, bool *different_types_p)
+			 struct comptypes_data *data)
 {
-  /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
-  int val = 1;
-  int newval = 0;
-
   while (1)
     {
       tree a1, mv1, a2, mv2;
       if (args1 == NULL_TREE && args2 == NULL_TREE)
-	return val;
+	return true;
       /* If one list is shorter than the other,
 	 they fail to match.  */
       if (args1 == NULL_TREE || args2 == NULL_TREE)
@@ -1740,9 +1711,8 @@  type_lists_compatible_p (const_tree args1, const_tree args2,
 	 means there is supposed to be an argument
 	 but nothing is specified about what type it has.
 	 So match anything that self-promotes.  */
-      if (different_types_p != NULL
-	  && (a1 == NULL_TREE) != (a2 == NULL_TREE))
-	*different_types_p = true;
+      if ((a1 == NULL_TREE) != (a2 == NULL_TREE))
+	data->different_types_p = true;
       if (a1 == NULL_TREE)
 	{
 	  if (c_type_promotes_to (a2) != a2)
@@ -1757,11 +1727,9 @@  type_lists_compatible_p (const_tree args1, const_tree args2,
       else if (TREE_CODE (a1) == ERROR_MARK
 	       || TREE_CODE (a2) == ERROR_MARK)
 	;
-      else if (!(newval = comptypes_internal (mv1, mv2, enum_and_int_p,
-					      different_types_p)))
+      else if (!comptypes_internal (mv1, mv2, data))
 	{
-	  if (different_types_p != NULL)
-	    *different_types_p = true;
+	  data->different_types_p = true;
 	  /* Allow  wait (union {union wait *u; int *i} *)
 	     and  wait (union wait *)  to be compatible.  */
 	  if (TREE_CODE (a1) == UNION_TYPE
@@ -1782,8 +1750,7 @@  type_lists_compatible_p (const_tree args1, const_tree args2,
 			   ? c_build_qualified_type (TYPE_MAIN_VARIANT (mv3),
 						     TYPE_QUAL_ATOMIC)
 			   : TYPE_MAIN_VARIANT (mv3));
-		  if (comptypes_internal (mv3, mv2, enum_and_int_p,
-					  different_types_p))
+		  if (comptypes_internal (mv3, mv2, data))
 		    break;
 		}
 	      if (memb == NULL_TREE)
@@ -1807,8 +1774,7 @@  type_lists_compatible_p (const_tree args1, const_tree args2,
 			   ? c_build_qualified_type (TYPE_MAIN_VARIANT (mv3),
 						     TYPE_QUAL_ATOMIC)
 			   : TYPE_MAIN_VARIANT (mv3));
-		  if (comptypes_internal (mv3, mv1, enum_and_int_p,
-					  different_types_p))
+		  if (comptypes_internal (mv3, mv1, data))
 		    break;
 		}
 	      if (memb == NULL_TREE)
@@ -1818,10 +1784,6 @@  type_lists_compatible_p (const_tree args1, const_tree args2,
 	    return 0;
 	}
 
-      /* comptypes said ok, but record if it said to warn.  */
-      if (newval > val)
-	val = newval;
-
       args1 = TREE_CHAIN (args1);
       args2 = TREE_CHAIN (args2);
     }
@@ -7298,7 +7260,7 @@  convert_for_assignment (location_t location, location_t expr_loc, tree type,
       tree mvl = ttl;
       tree mvr = ttr;
       bool is_opaque_pointer;
-      int target_cmp = 0;   /* Cache comp_target_types () result.  */
+      bool target_cmp = false;   /* Cache comp_target_types () result.  */
       addr_space_t asl;
       addr_space_t asr;