S/390: Add support for double<->long vector converts

S/390: Add support for double<->long vector converts

gcc/ChangeLog:

2018-12-21  Andreas Krebbel  <krebbel@linux.ibm.com>

	* config/s390/vector.md ("floatv2div2df2", "floatunsv2div2df2")
	("fix_truncv2dfv2di2", "fixuns_truncv2dfv2di2"): New pattern
	definitions.

gcc/testsuite/ChangeLog:

2018-12-21  Andreas Krebbel  <krebbel@linux.ibm.com>

	* gcc.target/s390/vector/fp-signedint-convert-1.c: New test.
	* gcc.target/s390/vector/fp-unsignedint-convert-1.c: New test.

From-SVN: r267336