The HI/QI atomic_fetch_<atomic><mode>" expander accepted symbolic
references and emitted CAS patterns whose insn predicates rejected them.

Fixed by allowing symbolic references there as well.  Reload will get
rid of them due to the constraint letter.

Regression tested on s390x.

gcc/ChangeLog:

2017-07-27  Andreas Krebbel  <krebbel@linux.vnet.ibm.com>

	PR target/81534
	* config/s390/s390.md ("*atomic_compare_and_swap<mode>_1")
	("*atomic_compare_and_swapdi_2", "*atomic_compare_and_swapsi_3"):
	Change s_operand to memory_operand.

gcc/testsuite/ChangeLog:

2017-07-27  Andreas Krebbel  <krebbel@linux.vnet.ibm.com>

	PR target/81534
	* gcc.target/s390/pr81534.c: New test.

From-SVN: r250617