Wattributes.c testcase: Disable warning check for IBM Z.

On IBM Z we enforce function alignment to 8 bytes.  Hence we get an
error instead of a warning when trying to specify smaller alignments.

gcc/testsuite/ChangeLog:

2018-04-06  Andreas Krebbel  <krebbel@linux.vnet.ibm.com>

	* c-c++-common/Wattributes.c: Disable warning for s390* target and
	check for an error instead.
	* gcc.dg/Wattributes-6.c: Likewise.

From-SVN: r259163

gcc/testsuite/ChangeLog

+2018-04-06  Andreas Krebbel  <krebbel@linux.vnet.ibm.com>
+
+	* c-c++-common/Wattributes.c: Disable warning for s390* target and
+	check for an error instead.
+	* gcc.dg/Wattributes-6.c: Likewise.
+
 2018-04-05  Jakub Jelinek  <jakub@redhat.com>
 
 	PR c++/85209

gcc/testsuite/c-c++-common/Wattributes.c

@@ -401,7 +401,8 @@ inline int ATTR ((warn_unused_result))
 finline_hot_noret_align (int);  /* { dg-warning "ignoring attribute .warn_unused_result. because it conflicts with attribute .noreturn." } */
 
 inline int ATTR ((aligned (4)))
-finline_hot_noret_align (int);  /* { dg-warning "ignoring attribute .aligned \\(4\\). because it conflicts with attribute .aligned \\(8\\)." } */
+  finline_hot_noret_align (int);  /* { dg-warning "ignoring attribute .aligned \\(4\\). because it conflicts with attribute .aligned \\(8\\)." "" { target { ! s390*-*-* } } } */
+/* { dg-error "alignment for '.*finline_hot_noret_align.*' must be at least 8" "" { target s390*-*-* } .-1 } */
 
 inline int ATTR ((aligned (8)))
 finline_hot_noret_align (int);

gcc/testsuite/gcc.dg/Wattributes-6.c

@@ -401,7 +401,8 @@ inline int ATTR ((warn_unused_result))
 finline_hot_noret_align (int);  /* { dg-warning "ignoring attribute .warn_unused_result. because it conflicts with attribute .noreturn." } */
 
 inline int ATTR ((aligned (4)))
-finline_hot_noret_align (int);  /* { dg-warning "ignoring attribute .aligned \\(4\\). because it conflicts with attribute .aligned \\(8\\)." } */
+  finline_hot_noret_align (int);  /* { dg-warning "ignoring attribute .aligned \\(4\\). because it conflicts with attribute .aligned \\(8\\)." "" { target { ! s390*-*-* } } } */
+/* { dg-error "alignment for 'finline_hot_noret_align' must be at least 8" "" { target s390*-*-* } .-1 } */
 
 inline int ATTR ((aligned (8)))
 finline_hot_noret_align (int);