re PR target/83862 (powerpc: ICE in signbit testcase)

re PR target/83862 (powerpc: ICE in signbit testcase)

[gcc]
2018-01-22  Michael Meissner  <meissner@linux.vnet.ibm.com>

	PR target/83862
	* config/rs6000/rs6000-protos.h (rs6000_split_signbit): Delete,
	no longer used.
	* config/rs6000/rs6000.c (rs6000_split_signbit): Likewise.
	* config/rs6000/rs6000.md (signbit<mode>2): Change code for IEEE
	128-bit to produce an UNSPEC move to get the double word with the
	signbit and then a shift directly to do signbit.
	(signbit<mode>2_dm): Replace old IEEE 128-bit signbit
	implementation with a new version that just does either a direct
	move or a regular move.  Move memory interface to separate insns.
	Move insns so they are next to the expander.
	(signbit<mode>2_dm_mem_be): New combiner insns to combine load
	with signbit move.  Split big and little endian case.
	(signbit<mode>2_dm_mem_le): Likewise.
	(signbit<mode>2_dm_<su>ext): Delete, no longer used.
	(signbit<mode>2_dm2): Likewise.

[gcc/testsuite]
2018-01-22  Michael Meissner  <meissner@linux.vnet.ibm.com>

	PR target/83862
	* gcc.target/powerpc/pr83862.c: New test.

From-SVN: r256959