re PR target/70381 (On powerpc, -mfloat128 is on by default for all VSX systems)

[gcc]
2016-04-11  Michael Meissner  <meissner@linux.vnet.ibm.com>

	PR target/70381
	* config/rs6000/rs6000.c (rs6000_opt_masks): Disable using the
	target attribute and pragma from changing the -mfloat128
	and -mfloat128-hardware options.

	* doc/extend.texi (Additional Floating Types): Document PowerPC
	__float128 restrictions.

[libgcc]
2016-04-11  Michael Meissner  <meissner@linux.vnet.ibm.com>

	PR target/70381
	* configure.ac (powerpc*-*-linux*): Rework tests to build
	__float128 emulation routines to not depend on using #pragma GCC
	target to enable -mfloat128.
	* configure: Regnerate.

[gcc/testsuite]
2016-04-11  Michael Meissner  <meissner@linux.vnet.ibm.com>

	PR target/70381
	* gcc.target/powerpc/float128-1.c: New tests to make sure the
	__float128 emulator is built and runs.
	* gcc.target/powerpc/float128-1.c: Likewise.

	* lib/target-supports.exp (check_ppc_float128_sw_available):
	Rework tests for __float128 software and hardware
	availability. Fix exit condition to return 0 on success.

From-SVN: r234884