aix.h (TARGET_IEEEQUAD_DEFAULT): Set long double default to IBM.

aix.h (TARGET_IEEEQUAD_DEFAULT): Set long double default to IBM.

[gcc]
2017-10-26  Michael Meissner  <meissner@linux.vnet.ibm.com>

	* config/rs6000/aix.h (TARGET_IEEEQUAD_DEFAULT): Set long double
	default to IBM.
	* config/rs6000/darwin.h (TARGET_IEEEQUAD_DEFAULT): Likewise.
	* config/rs6000/rs6000.opt (-mabi=ieeelongdouble): Move the
	warning to rs6000.c.  Remove the Undocumented flag, since it has
	been documented.
	(-mabi=ibmlongdouble): Likewise.
	* config/rs6000/rs6000.c (TARGET_IEEEQUAD_DEFAULT): If it is not
	already set, set the default format for long double.
	(rs6000_debug_reg_global): Print whether long double is IBM or
	IEEE.
	(rs6000_option_override_internal): Rework setting long double
	format.  Only warn if the user is changing the long double default
	and they did not use -Wno-psabi.
	* doc/invoke.texi (PowerPC options): Update the documentation for
	-mabi=ieeelongdouble and -mabi=ibmlongdouble.

From-SVN: r254116