re PR target/71677 (PowerPC ISA 3.0 DImode load/store needs a fix)

re PR target/71677 (PowerPC ISA 3.0 DImode load/store needs a fix)

2016-06-30  Michael Meissner  <meissner@linux.vnet.ibm.com>

	PR target/71677
	* config/rs6000/constraints.md (wY constraint): New constraint to
	match the requirements for the LXSD and STXSD instructions.
	* config/rs6000/predicates.md (offsettable_mem_14bit_operand): New
	predicate to match the requirements for the LXSD and STXSD
	instructions.
	* config/rs6000/rs6000.md (mov<mode>_hardfloat32, FMOVE64 case):
	Use constaint wY for LXSD/STXSD instructions instead of 'o' or 'Y'
	to make sure that the bottom 2 bits of offset are 0, the address
	form is offsettable, and no updating is done in the address mode.
	(mov<mode>_hardfloat64, FMOVE64 case): Likewise.
	(movdi_internal32): Likewise
	(movdi_internal64): Likewise.

From-SVN: r237898