re PR target/71806 (PowerPC -mcpu=power9 enables __float128 without an explicit ...

re PR target/71806 (PowerPC -mcpu=power9 enables __float128 without an explicit -mfloat128)

[gcc]
2016-07-08  Michael Meissner  <meissner@linux.vnet.ibm.com>

	PR target/71806
	* config/rs6000/rs6000-cpus.def (ISA_3_0_MASKS_SERVER): Do not
	enable -mfloat128-hardware by default.
	(ISA_3_0_MASKS_IEEE): New macro to give all of the VSX options
	that IEEE 128-bit hardware support needs.
	* config/rs6000/rs6000.c (rs6000_option_override_internal): If
	-mcpu=power9 -mfloat128, enable -mfloat128-hardware by default.
	Use ISA_3_0_MASKS_IEEE as the set of options that IEEE 128-bit
	floating point requires.
	* doc/invoke.texi (RS/6000 and PowerPC Options): Document
	-mfloat128 and -mfloat128-hardware changes.

[gcc/testsuite]
2016-07-08  Michael Meissner  <meissner@linux.vnet.ibm.com>

	PR target/71806
	* gcc.target/powerpc/p9-lxvx-stxvx-3.c: Add -mfloat128 option.

From-SVN: r238164