re PR target/38931 (Seg fault when getting instruction latency on a *movsi_1 with an MMX target register)

	PR target/38931
	* config/i386/i386.md (*movsi_1): Use type "mmx" for alternative 2.
	(*movdi_1_rex64): Use type "mmx" for alternative 5.

testsuite/ChangeLog:

	PR target/38931
	* gcc.target/i386/pr38931.c: New test.

From-SVN: r143567