S/390: arch13: Add support for new select instruction

S/390: arch13: Add support for new select instruction

Compared to the load on condition instructions we already have the new
select instruction allows to have a THEN and and ELSE source operand -
but only for register to register loads.

gcc/ChangeLog:

2019-04-02  Andreas Krebbel  <krebbel@linux.ibm.com>

	* config/s390/s390.c (s390_rtx_costs): Do not add extra costs for
	if-then-else constructs if we can use the select instruction.
	* config/s390/s390.md ("*mov<mode>cc"): Add the new instructions.

gcc/testsuite/ChangeLog:

2019-04-02  Andreas Krebbel  <krebbel@linux.ibm.com>

	* gcc.target/s390/arch13/sel-1.c: New test.

From-SVN: r270080