PR c/15052

	* c-decl.c (grokdeclarator): Only pedwarn for qualified void
	return type on function definitions.  Move other warnings for
	qualified return type to -Wreturn-type.  Do not condition any such
	warnings on -pedantic.  Update comments.
	(start_function): Only copy function type from previous prototype
	declaration if return types are compatible.
	* c-typeck.c (function_types_compatible_p): Don't condition
	warning for incompatibility of volatile qualifiers on the return
	type on -pedantic.  Update comment.
	* doc/invoke.texi (-Wreturn-type, -Wextra): Update.

testsuite:
	* gcc.dg/noreturn-5.c: Test qualifiers on function type instead of
	on return type.
	* gcc.dg/qual-return-1.c: Use -Wreturn-type.  Update expected
	messages.
	* gcc.dg/qual-return-2.c: Update expected messages.
	* gcc.dg/qual-return-3.c, gcc.dg/qual-return-4.c: New tests.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@85024 138bc75d-0d04-0410-961f-82ee72b054a4

5 files changed, 37 insertions, 13 deletions

diff --git a/gcc/testsuite/gcc.dg/noreturn-5.c b/gcc/testsuite/gcc.dg/noreturn-5.c
index 07381a66d24..e69087a4d74 100644
--- a/gcc/testsuite/gcc.dg/noreturn-5.c
+++ b/gcc/testsuite/gcc.dg/noreturn-5.c
@@ -4,4 +4,5 @@
    The testsuite uses -ansi -pedantic-errors by default, so this has
    to override.  */
 extern void xxx (int) __attribute__((noreturn));
-__volatile extern void xxx (int);
+typedef void voidfn (int);
+__volatile extern voidfn xxx;
diff --git a/gcc/testsuite/gcc.dg/qual-return-1.c b/gcc/testsuite/gcc.dg/qual-return-1.c
index 5cab75c93d7..ac94df6d2bb 100644
--- a/gcc/testsuite/gcc.dg/qual-return-1.c
+++ b/gcc/testsuite/gcc.dg/qual-return-1.c
@@ -1,7 +1,7 @@
 /* Test for warnings for qualified function return types.  */
 /* Origin: Joseph Myers <jsm28@cam.ac.uk> */
 /* { dg-do compile } */
-/* { dg-options "-std=gnu99 -W" } */
+/* { dg-options "-std=gnu99 -Wreturn-type" } */
 
 /* Qualifying a function return type makes no sense.  */
 
@@ -11,13 +11,11 @@ const int int_fn2 (void) { return 0; } /* { dg-warning "qualifiers" "int defn" }
 
 const void void_fn (void); /* { dg-warning "qualifiers" "void decl" } */
 const void (*void_ptr) (void); /* { dg-warning "qualifiers" "void ptr" } */
-const void void_fn2 (void) { } /* { dg-warning "qualifiers" "void defn" } */
+const void void_fn2 (void) { } /* { dg-warning "qualified" "void defn" } */
 
-/* "volatile void" is a GNU extension, so only warn at -pedantic.  */
-
-volatile void vvoid_fn (void);
-volatile void (*vvoid_ptr) (void);
-volatile void vvoid_fn2 (void) { }
+volatile void vvoid_fn (void); /* { dg-warning "qualifiers" "void decl" } */
+volatile void (*vvoid_ptr) (void); /* { dg-warning "qualifiers" "void ptr" } */
+volatile void vvoid_fn2 (void) { } /* { dg-warning "qualified" "void defn" } */
 
 int *restrict ip_fn (void); /* { dg-warning "qualifiers" "restrict decl" } */
 int *restrict (*ip_ptr) (void); /* { dg-warning "qualifiers" "restrict ptr" } */
diff --git a/gcc/testsuite/gcc.dg/qual-return-2.c b/gcc/testsuite/gcc.dg/qual-return-2.c
index 272787ee7c2..22a1946b03f 100644
--- a/gcc/testsuite/gcc.dg/qual-return-2.c
+++ b/gcc/testsuite/gcc.dg/qual-return-2.c
@@ -5,10 +5,9 @@
 
 /* Qualifying a function return type makes no sense.  */
 
-/* "volatile void" is a GNU extension, so only warn at -pedantic.
-   Strictly, the first two of these should warn only if the function is
-   somewhere used or defined.  */
+/* The first two of these shouldn't warn (with just -pedantic) as long
+   as the function is not defined.  */
 
-volatile void vvoid_fn (void); /* { dg-warning "qualified" "volatile decl" } */
-volatile void (*vvoid_ptr) (void); /* { dg-warning "qualified" "volatile ptr" } */
+volatile void vvoid_fn (void);
+volatile void (*vvoid_ptr) (void);
 volatile void vvoid_fn2 (void) { } /* { dg-warning "qualified" "volatile defn" } */
diff --git a/gcc/testsuite/gcc.dg/qual-return-3.c b/gcc/testsuite/gcc.dg/qual-return-3.c
new file mode 100644
index 00000000000..7a92046da81
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/qual-return-3.c
@@ -0,0 +1,16 @@
+/* Test for warnings for qualified function return types.  Bug 15052
+   from Olatunji Ruwase (tjruwase at stanfordalumni.org): qualifiers
+   should not be lost when merging declarations.  */
+
+/* Origin: Joseph Myers <jsm@polyomino.org.uk> */
+/* { dg-do compile } */
+/* { dg-options "" } */
+
+int foo (); /* { dg-error "previous declaration" "different qualifiers" } */
+const int foo () { return 0; } /* { dg-error "conflicting types" "different qualifiers" } */
+
+void bar (void);
+volatile void bar () { } /* { dg-warning "qualified|volatile" "different qualifiers" } */
+
+volatile void baz (void);
+void baz () { } /* { dg-warning "not compatible" "different qualifiers" } */
diff --git a/gcc/testsuite/gcc.dg/qual-return-4.c b/gcc/testsuite/gcc.dg/qual-return-4.c
new file mode 100644
index 00000000000..9b61cfebf12
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/qual-return-4.c
@@ -0,0 +1,10 @@
+/* Test for warnings for qualified function return types.  -pedantic
+   test.  Only the definition gets a warning for qualified void return
+   types, not other such types within the definition.  */
+/* Origin: Joseph Myers <jsm@polyomino.org.uk> */
+/* { dg-do compile } */
+/* { dg-options "-pedantic" } */
+
+volatile void (*y)(int);
+
+volatile void (*vvf(int x))(int) { return y; }