re PR target/85358 (PowerPC: Using -mabi=ieeelongdouble -mcpu=power9 breaks __ibm128)

re PR target/85358 (PowerPC: Using -mabi=ieeelongdouble -mcpu=power9 breaks __ibm128)

[gcc]
2018-06-18  Michael Meissner  <meissner@linux.ibm.com>

	PR target/85358
	* config/rs6000/rs6000-modes.def (toplevel): Rework the 128-bit
	floating point modes, so that IFmode is numerically greater than
	TFmode, which is greater than KFmode using FRACTIONAL_FLOAT_MODE
	to declare the ordering.  This prevents IFmode from being
	converted to TFmode when long double is IEEE 128-bit on an ISA 3.0
	machine.  Include rs6000-modes.h to share the fractional values
	between genmodes* and the rest of the compiler.
	(IFmode): Likewise.
	(KFmode): Likewise.
	(TFmode): Likewise.
	* config/rs6000/rs6000-modes.h: New file.
	* config/rs6000/rs6000.c (rs6000_debug_reg_global): Change the
	meaning of rs6000_long_double_size so that 126..128 selects an
	appropriate 128-bit floating point type.
	(rs6000_option_override_internal): Likewise.
	* config/rs6000/rs6000.h (toplevel): Include rs6000-modes.h.
	(TARGET_LONG_DOUBLE_128): Change the meaning of
	rs6000_long_double_size so that 126..128 selects an appropriate
	128-bit floating point type.
	(LONG_DOUBLE_TYPE_SIZE): Update comment.
	* config/rs6000/rs6000.md (trunciftf2): Correct the modes of the
	source and destination to match the standard usage.
	(truncifkf2): Likewise.
	(copysign<mode>3, IEEE iterator): Rework copysign of float128 on
	ISA 2.07 to use an explicit clobber, instead of passing in a
	temporary.
	(copysign<mode>3_soft): Likewise.

[libgcc]
2018-06-18  Michael Meissner  <meissner@linux.ibm.com>

	* config/rs6000/t-float128 (FP128_CFLAGS_SW): Compile float128
	support modules with -mno-gnu-attribute.
	* config/rs6000/t-float128-hw (FP128_CFLAGS_HW): Likewise.

From-SVN: r261712