PR other/81345 - -Wall resets -Wstringop-overflow to 1 from the default 2

gcc/c-family/ChangeLog:

	PR other/81345
	* c.opt (-Wstringop-overflow): Set defaults in LangEnabledBy.

gcc/testsuite/ChangeLog:

	PR other/81345
	* gcc.dg/pr81345.c: New test.

From-SVN: r250104

gcc/c-family/ChangeLog

+2017-07-10  Martin Sebor  <msebor@redhat.com>
+
+	PR other/81345
+	* c.opt (-Wstringop-overflow): Set defaults in LangEnabledBy.
+
 2017-07-06  David Malcolm  <dmalcolm@redhat.com>
 
 	* c-common.c (selftest::c_family_tests): New.

gcc/c-family/c.opt

@@ -732,7 +732,7 @@ Warn about buffer overflow in string manipulation functions like memcpy
 and strcpy.
 
 Wstringop-overflow=
-C ObjC C++ ObjC++ Joined RejectNegative UInteger Var(warn_stringop_overflow) Init(2) Warning LangEnabledBy(C ObjC C++ ObjC++, Wall) IntegerRange(0, 4)
+C ObjC C++ ObjC++ Joined RejectNegative UInteger Var(warn_stringop_overflow) Init(2) Warning LangEnabledBy(C ObjC C++ ObjC++, Wall, 2, 0) IntegerRange(0, 4)
 Under the control of Object Size type, warn about buffer overflow in string
 manipulation functions like memcpy and strcpy.
 

gcc/testsuite/ChangeLog

+2017-07-10  Martin Sebor  <msebor@redhat.com>
+
+	PR other/81345
+	* gcc.dg/pr81345.c: New test.
+
 2017-07-10  Claudiu Zissulescu  <claziss@synopsys.com>
 
 	* gcc.target/arc/mulsi3_highpart-1.c: Remove 'X' constraint.

gcc/testsuite/gcc.dg/pr81345.c

+/* PR other/81345 - -Wall resets -Wstringop-overflow to 1 from the default 2
+   { dg-do compile }
+   { dg-options "-O2 -Wall" } */
+
+char a[3];
+
+void f (const char *s)
+{
+  __builtin_strncpy (a, s, sizeof a + 1);   /* { dg-warning "\\\[-Wstringop-overflow=]" } */
+}
+
+struct S { char a[3]; int i; };
+
+void g (struct S *d, const char *s)
+{
+  __builtin_strncpy (d->a, s, sizeof d->a + 1);   /* { dg-warning "\\\[-Wstringop-overflow=]" } */
+}