re PR c/6024 (GCC fails to diagnose mismatch of enum types in prototype/function)

PR c/6024
	* c-typeck.c (comptypes): Only treat enumerated types in the same
	translation unit as compatible with each other when they are the
	same type.
	* doc/extend.texi: Update.

f:
	* com.h (ffecom_gfrt_basictype): Correct return type.

testsuite:
	* gcc.dg/enum-compat-1.c: New test.
	* gcc.c-torture/execute/builtin-types-compatible-p.c: Update.

From-SVN: r75521

gcc/ChangeLog

@@ -1,3 +1,11 @@
+2004-01-07  Joseph S. Myers  <jsm@polyomino.org.uk>
+
+	PR c/6024
+	* c-typeck.c (comptypes): Only treat enumerated types in the same
+	translation unit as compatible with each other when they are the
+	same type.
+	* doc/extend.texi: Update.
+
 2004-01-07  Joseph S. Myers  <jsm@polyomino.org.uk>
 
 	PR c/12165

gcc/c-typeck.c

@@ -474,12 +474,13 @@ comptypes (tree type1, tree type2, int flags)
       && TYPE_DOMAIN (t2) != 0)
     t2 = TYPE_DOMAIN (t2);
 
-  /* Treat an enum type as the integer type of the same width and
-     signedness.  */
+  /* Enumerated types are compatible with integer types, but this is
+     not transitive: two enumerated types in the same translation unit
+     are compatible with each other only if they are the same type.  */
 
-  if (TREE_CODE (t1) == ENUMERAL_TYPE)
+  if (TREE_CODE (t1) == ENUMERAL_TYPE && TREE_CODE (t2) != ENUMERAL_TYPE)
     t1 = c_common_type_for_size (TYPE_PRECISION (t1), TREE_UNSIGNED (t1));
-  if (TREE_CODE (t2) == ENUMERAL_TYPE)
+  else if (TREE_CODE (t2) == ENUMERAL_TYPE && TREE_CODE (t1) != ENUMERAL_TYPE)
     t2 = c_common_type_for_size (TYPE_PRECISION (t2), TREE_UNSIGNED (t2));
 
   if (t1 == t2)

gcc/doc/extend.texi

@@ -5265,8 +5265,10 @@ similarity.  Consequently, @code{short *} is not similar to
 @code{short **}.  Furthermore, two types that are typedefed are
 considered compatible if their underlying types are compatible.
 
-An @code{enum} type is considered to be compatible with another
-@code{enum} type.  For example, @code{enum @{foo, bar@}} is similar to
+An @code{enum} type is not considered to be compatible with another
+@code{enum} type even if both are compatible with the same integer
+type; this is what the C standard specifies.
+For example, @code{enum @{foo, bar@}} is not similar to
 @code{enum @{hot, dog@}}.
 
 You would typically use this function in code whose execution varies

gcc/f/ChangeLog

@@ -1,3 +1,7 @@
+2004-01-07  Joseph S. Myers  <jsm@polyomino.org.uk>
+
+	* com.h (ffecom_gfrt_basictype): Correct return type.
+
 2003-12-29  Roger Sayle  <roger@eyesopen.com>
 
 	PR fortran/12632

gcc/f/com.h

@@ -1,5 +1,5 @@
 /* com.h -- Public #include File (module.h template V1.0)
-   Copyright (C) 1995, 1996, 1997, 2000, 2003
+   Copyright (C) 1995, 1996, 1997, 2000, 2003, 2004
    Free Software Foundation, Inc.
    Contributed by James Craig Burley.
 
@@ -228,7 +228,7 @@ void ffecom_finish_decl (tree decl, tree init, bool is_top_level);
 void ffecom_finish_progunit (void);
 tree ffecom_get_invented_identifier (const char *pattern, ...)
   ATTRIBUTE_PRINTF_1;
-ffeinfoKindtype ffecom_gfrt_basictype (ffecomGfrt ix);
+ffeinfoBasictype ffecom_gfrt_basictype (ffecomGfrt ix);
 ffeinfoKindtype ffecom_gfrt_kindtype (ffecomGfrt ix);
 void ffecom_init_0 (void);
 void ffecom_init_2 (void);

gcc/testsuite/ChangeLog

@@ -1,3 +1,9 @@
+2004-01-07  Joseph S. Myers  <jsm@polyomino.org.uk>
+
+	PR c/6024
+	* gcc.dg/enum-compat-1.c: New test.
+	* gcc.c-torture/execute/builtin-types-compatible-p.c: Update.
+
 2004-01-07  Joseph S. Myers  <jsm@polyomino.org.uk>
 
 	PR c/12165

gcc/testsuite/gcc.c-torture/execute/builtin-types-compatible-p.c

@@ -19,7 +19,6 @@ int main (void)
 	&& __builtin_types_compatible_p (typeof (hot), int)
 	&& __builtin_types_compatible_p (typeof (hot), typeof (laura))
 	&& __builtin_types_compatible_p (int[5], int[])
-	&& __builtin_types_compatible_p (typeof (dingos), typeof (cranberry))
 	&& __builtin_types_compatible_p (same1, same2)))
     abort ();
 
@@ -28,6 +27,7 @@ int main (void)
       || __builtin_types_compatible_p (char *, const char *)
       || __builtin_types_compatible_p (long double, double)
       || __builtin_types_compatible_p (typeof (i), typeof (d))
+      || __builtin_types_compatible_p (typeof (dingos), typeof (cranberry))
       || __builtin_types_compatible_p (char, int)
       || __builtin_types_compatible_p (char *, char **))
     abort ();

gcc/testsuite/gcc.dg/enum-compat-1.c

@@ -0,0 +1,32 @@
+/* Test that enumerated types are only considered compatible when they
+   are the same type.  PR c/6024.  */
+/* Origin: Joseph Myers <jsm@polyomino.org.uk>, based on
+   PR c/6024 from Richard Earnshaw <rearnsha@arm.com> */
+/* { dg-do compile } */
+/* { dg-options "" } */
+
+/* Original test from PR c/6024.  */
+enum e1 {a, b};
+enum e2 {c, d};
+
+void f(enum e1); /* { dg-error "prototype" "error at decl" } */
+
+void f(x)
+     enum e2 x;
+{ /* { dg-error "doesn't match prototype" "error at defn" } */
+  return;
+}
+
+/* Other compatibility tests.  */
+enum e3 { A };
+enum e4 { B };
+
+enum e3 v3;
+enum e4 *p = &v3; /* { dg-warning "incompatible" "incompatible pointer" } */
+enum e3 *q = &v3;
+
+void g(enum e3); /* { dg-error "declaration" "error at first decl" } */
+void g(enum e4); /* { dg-error "conflicting types" "error at second decl" } */
+
+void h(enum e3);
+void h(enum e3);