Patch for bug 6980

["Joseph S. Myers" <jsm at polyomino dot org dot uk>]

This patch fixes bug 6980, which complained of the misleading wording
of the diagnostic for -Wbad-function-cast (not a warning I
particularly find useful myself, but the wording could indeed do with
improvement).  It adds an associated testcase for -Wbad-function-cast,
which did not have any testsuite coverage.

Bootstrapped with no regressions on i686-pc-linux-gnu.  Applied to
mainline.

-- 
Joseph S. Myers               http://www.srcf.ucam.org/~jsm28/gcc/
  http://www.srcf.ucam.org/~jsm28/gcc/#c90status - status of C90 for GCC 4.0
    jsm@polyomino.org.uk (personal mail)
    jsm28@gcc.gnu.org (Bugzilla assignments and CCs)

2004-09-24  Joseph S. Myers  <jsm@polyomino.org.uk>

	PR c/6980
	* c-typeck.c (build_c_cast): Improve wording of
	-Wbad-function-cast diagnostic.

testsuite:
2004-09-24  Joseph S. Myers  <jsm@polyomino.org.uk>

	PR c/6980
	* gcc.dg/Wbad-function-cast-1.c: New test.

diff -rupN GCC.orig/gcc/c-typeck.c GCC/gcc/c-typeck.c
--- GCC.orig/gcc/c-typeck.c	2004-09-22 22:47:59.000000000 +0000
+++ GCC/gcc/c-typeck.c	2004-09-23 14:02:11.000000000 +0000
@@ -3138,7 +3138,8 @@ build_c_cast (tree type, tree expr)
       if (warn_bad_function_cast
 	  && TREE_CODE (value) == CALL_EXPR
 	  && TREE_CODE (type) != TREE_CODE (otype))
-	warning ("cast does not match function type");
+	warning ("cast from function call of type %qT to non-matching "
+		 "type %qT", otype, type);
 
       if (TREE_CODE (type) == POINTER_TYPE
 	  && TREE_CODE (otype) == INTEGER_TYPE
diff -rupN GCC.orig/gcc/testsuite/gcc.dg/Wbad-function-cast-1.c GCC/gcc/testsuite/gcc.dg/Wbad-function-cast-1.c
--- GCC.orig/gcc/testsuite/gcc.dg/Wbad-function-cast-1.c	1970-01-01 00:00:00.000000000 +0000
+++ GCC/gcc/testsuite/gcc.dg/Wbad-function-cast-1.c	2004-09-23 23:03:52.000000000 +0000
@@ -0,0 +1,51 @@
+/* Test operation of -Wbad-function-cast.  Bug 6980 complained of the
+   wording of the diagnostic.  */
+/* Origin: Joseph Myers <jsm@polyomino.org.uk> */
+/* { dg-do compile } */
+/* { dg-options "-Wbad-function-cast" } */
+
+void vf(void);
+int if1(void);
+char if2(void);
+long if3(void);
+float rf1(void);
+double rf2(void);
+_Complex double cf(void);
+enum e { E1 } ef(void);
+_Bool bf(void);
+char *pf1(void);
+int *pf2(void);
+
+void
+foo(void)
+{
+  /* Casts to void types are always OK.  */
+  (void)vf();
+  (void)if1();
+  (void)cf();
+  (const void)bf();
+  /* Casts to the same type or similar types are OK.  */
+  (int)if1();
+  (long)if2();
+  (char)if3();
+  (float)rf1();
+  (long double)rf2();
+  (_Complex float)cf();
+  (enum f { F1 })ef();
+  (_Bool)bf();
+  (void *)pf1();
+  (char *)pf2();
+  /* Casts to types with different TREE_CODE (which is how this
+     warning has been defined) are not OK, except for casts to void
+     types.  */
+  (float)if1(); /* { dg-warning "cast from function call of type 'int' to non-matching type 'float'" } */
+  (double)if2(); /* { dg-warning "cast from function call of type 'char' to non-matching type 'double'" } */
+  (_Bool)if3(); /* { dg-warning "cast from function call of type 'long int' to non-matching type '_Bool'" } */
+  (int)rf1(); /* { dg-warning "cast from function call of type 'float' to non-matching type 'int'" } */
+  (long)rf2(); /* { dg-warning "cast from function call of type 'double' to non-matching type 'long int'" } */
+  (double)cf(); /* { dg-warning "cast from function call of type 'complex double' to non-matching type 'double'" } */
+  (int)ef(); /* { dg-warning "cast from function call of type 'enum e' to non-matching type 'int'" } */
+  (int)bf(); /* { dg-warning "cast from function call of type '_Bool' to non-matching type 'int'" } */
+  (__SIZE_TYPE__)pf1(); /* { dg-warning "cast from function call of type 'char \\*' to non-matching type '\[^\\n\]*'" } */
+  (__PTRDIFF_TYPE__)pf2(); /* { dg-warning "cast from function call of type 'int \\*' to non-matching type '\[^\\n\]*'" } */
+}