re PR target/84154 (PowerPC GCC 7 and 8 have regression in converting fp to short/char and returning it)

[gcc]
2018-02-07  Michael Meissner  <meissner@linux.vnet.ibm.com>

	PR target/84154
	* config/rs6000/rs6000.md (fix_trunc<SFDF:mode><QHI:mode>2):
	Convert from define_expand to be define_insn_and_split.  Rework
	float/double/_Float128 conversions to QI/HI/SImode to work with
	both ISA 2.07 (power8) or ISA 3.0 (power9).  Fix regression where
	conversions to QI/HImode types did a store and then a load to
	truncate the value.  For conversions to VSX registers, don't split
	the insn, instead emit the code directly.  Use the code iterator
	any_fix to combine signed and unsigned conversions.
	(fix<uns>_trunc<SFDF:mode>si2_p8): Likewise.
	(fixuns_trunc<SFDF:mode><QHI:mode>2): Likewise.
	(fix_trunc<IEEE128:mode><QHI:mode>2): Likewise.
	(fix<uns>_trunc<SFDF:mode><QHI:mode>2): Likewise.
	(fix_<mode>di2_hw): Likewise.
	(fixuns_<mode>di2_hw): Likewise.
	(fix_<mode>si2_hw): Likewise.
	(fixuns_<mode>si2_hw): Likewise.
	(fix<uns>_<IEEE128:mode><SDI:mode>2_hw): Likewise.
	(fix<uns>_trunc<IEEE128:mode><QHI:mode>2): Likewise.
	(fctiw<u>z_<mode>_smallint): Rename fctiw<u>z_<mode>_smallint to
	fix<uns>_trunc<SFDF:mode>si2_p8.
	(fix_trunc<SFDF:mode><QHI:mode>2_internal): Delete, no longer
	used.
	(fixuns_trunc<SFDF:mode><QHI:mode>2_internal): Likewise.
	(fix<uns>_<mode>_mem): Likewise.
	(fctiw<u>z_<mode>_mem): Likewise.
	(fix<uns>_<mode>_mem): Likewise.
	(fix<uns>_trunc<SFDF:mode><QHSI:mode>2_mem): On ISA 3.0, prevent
	the register allocator from doing a direct move to the GPRs to do
	a store, and instead use the ISA 3.0 store byte/half-word from
	vector register instruction.  For IEEE 128-bit floating point,
	also optimize stores of 32-bit ints.
	(fix<uns>_trunc<IEEE128:mode><QHSI:mode>2_mem): Likewise.

[gcc/testsuite]
2018-02-07  Michael Meissner  <meissner@linux.vnet.ibm.com>

	PR target/84154
	* gcc.target/powerpc/pr84154-1.c: New tests.
	* gcc.target/powerpc/pr84154-2.c: Likewise.
	* gcc.target/powerpc/pr84154-3.c: Likewise.

From-SVN: r257470