Fix -Wreturn-type for static naked functions in C

This patch extends the fix for PR53633 to include static functions,
which were giving a bogus -Wreturn-type warning for C but not for C++.

2019-07-18  Richard Sandiford  <richard.sandiford@arm.com>

gcc/c/
	PR c/53633
	* c-decl.c (finish_function): Check targetm.warn_func_return
	before issuing a -Wreturn-type warning.

gcc/testsuite/
	* c-c++-common/pr53633-2.c: New test.

From-SVN: r273568

gcc/c/ChangeLog

+2019-07-18  Richard Sandiford  <richard.sandiford@arm.com>
+
+	PR c/53633
+	* c-decl.c (finish_function): Check targetm.warn_func_return
+	before issuing a -Wreturn-type warning.
+
 2019-07-12  Alexandre Oliva <oliva@adacore.com>
 
 	* gimple-parser.c (c_parser_gimple_try_stmt): New.

gcc/c/c-decl.c

@@ -9687,6 +9687,7 @@ finish_function (void)
       /* Normally, with -Wreturn-type, flow will complain, but we might
          optimize out static functions.  */
       && !TREE_PUBLIC (fndecl)
+      && targetm.warn_func_return (fndecl)
       && warning (OPT_Wreturn_type,
 		  "no return statement in function returning non-void"))
     TREE_NO_WARNING (fndecl) = 1;

gcc/testsuite/ChangeLog

+2019-07-18  Richard Sandiford  <richard.sandiford@arm.com>
+
+	* c-c++-common/pr53633-2.c: New test.
+
 2019-07-17  Alexandre Oliva <oliva@adacore.com>
 
 	PR middle-end/81824

gcc/testsuite/c-c++-common/pr53633-2.c

+/* { dg-do compile } */
+/* { dg-require-effective-target naked_functions } */
+/* { dg-options "-O2 -Wall" } */
+/* Check that we do not get warnings about missing return statements
+   or bogus looking noreturn functions.  */
+static int __attribute__((naked))
+foo (void)
+{
+  __asm__ ("");
+}
+
+static int __attribute__((naked,noreturn))
+bar (void)
+{
+  __asm__ ("");
+}
+
+int foo_caller (void) { return foo (); }
+int bar_caller (void) { return bar (); }