re PR target/78602 (PowerPC vec-extract-v2df.c can fail if -mcpu=power9 -O0)

2016-11-30  Michael Meissner  <meissner@linux.vnet.ibm.com>

	PR target/78602
	* config/rs6000/rs6000.c (rs6000_expand_vector_extract): If the
	element is not a constant or in a register, force it to a
	register.

	PR target/78560
	* config/rs6000/rs6000.c (rs6000_expand_vector_set): Force value
	that will be set to a vector element to be in a register.
	* config/rs6000/vsx.md (vsx_set_<mode>_p9): Fix thinko that used
	the wrong multiplier to convert the element number to a byte
	offset.

From-SVN: r243044