S/390: Require a hardware vector support for test to succeed.

S/390: Require a hardware vector support for test to succeed.

The test case works on S/390 too, but only with -march=z13 or later
(i.e. if Gcc can make use of hardware vector support).  Otherwise the
optimization gets too complex.  The attached patch forces Gcc to use
-march=z13 instead of xfail'ing the test on S/390.

gcc/testsuite/ChangeLog

	* gcc.dg/tree-ssa/ssa-dom-cse-2.c: Require a hardware vector support for
	test to succeed.

From-SVN: r232971