Revert patch.

Revert patch.

2021-07-31  Michael Meissner  <meissner@linux.ibm.com>
gcc/

	Revert patch.
	PR target/98519
	* config/rs6000/constraints.md (top level): Adjust comment about
	the available unused constraints.
	(constraint "m").  New constraint.
	* config/rs6000/rs6000.h (TARGET_MEM_CONSTRAINT): Define, making
	'k' the new memory cosntraint.
	* config/rs6000/rs6000.md (ptrm): Use "k" instead of "m".
	(zero_extendqi<mode>2): Likewise.
	(zero_extendhi<mode>2): Likewise.
	(zero_extendsi<mode>2): Likewise.
	(extendhi<mode>2): Likewise.
	(signbit<mode>2_dm_mem): Likewise.
	(floatdidf2_mem): Likewise.
	(floatunsdidf2_mem): Likewise.
	(floatdisf2_mem): Likewise.
	(floatunsdisf2_mem): Likewise.
	(movsi_internal1): Likewise.
	(movdi_from_sf_zero_ext): Likewise.
	(mov<mode>_internal, QHI iterator): Likewise.
	(movsf_hardfloat): Likewise.
	(movsd_hardfloat): Likewise.
	(mov<mode>_softfloat): Likewise.
	(mov<mode>_hardfloat32): Likewise.
	(mov<mode>_hardfloat64): Likewise.
	(mov<mode>_64bit_dm): Likewise.
	(movtd_64bit_nodm): Likewise.
	(mov<mode>_32bit. FMOVE128 iterator): Likewise.
	(extenddf<mode>2, IBM128 iterator): Likewise.
	(extendtf<mode>2): Likewise.
	(reload_<mode>_load): Likewise.
	(reload_<RELOAD:mode>_<P:mptrsize>_load): Likewise.
	(movdi_internal32): Likewise.
	(movdi_internal64): Likewise.
	(pltseq_tocsave_<mode>): Likewise.
	(probe_stack_<mode>): Likewise.
	(stack_protect_setsi): Likewise.
	(stack_protect_testsi): Likewise.
	(crsave): Likewise.
	(stmw): Likewise.
	(save_gpregs_<mode>_r11): Likewise.
	(save_gpregs_<mode>_r12): Likewise.
	(save_gpregs_<mode>_r1): Likewise.
	(save_fpregs_<mode>_r11): Likewise.
	(save_fpregs_<mode>_r12): Likewise.
	(save_fpregs_<mode>_r1): Likewise.
	(mtcrfsi): Likewise.
	(restore_gpregs_<mode>_r11): Likewise.
	(restore_gpregs_<mode>_r12): Likewise.
	(restore_gpregs_<mode>_r1): Likewise.
	(return_and_restore_gpregs): Likewise.
	(return_and_restore_fpregs): Likewise.
	(hashst): Likewise.
	(hashchk): Likewise.

gcc/testsuite/

	Revert patch.
	PR target/98519
	* gcc.target/powerpc/pr98519.c: New test.