Remove gen_cell_microcode, warn_cell_microcode

Remove gen_cell_microcode, warn_cell_microcode

-mno-gen-cell-microcode is a pain to handle correctly: it causes
different code generation for some very basic patterns, even patterns
specific to that option.  It also requires marking up many patterns,
which is a pain when adding new patterns or modifying existing ones
(first non-trivial step is finding the Cell BE manual!)

-mwarn-cell-microcode is very expensive, even more so after my recent
fix for PR43763; and it used to ICE for seven years before that fix.

This patch removes both these command line options (it leaves the
positive form of -mgen-cell-microcode, doing nothing, for
compatibility).

Where cc_reg_not_micro_cr0_operand was used, we now get the regular
cc_reg_not_cr0_operand.

One testcase used -mgen-cell-microcode and one its negation; both
are adjusted.

	* config/rs6000/predicates.md (cc_reg_not_micro_cr0_operand): Delete.
	(lwa_operand): Delete rs6000_gen_cell_microcode test.
	* config/rs6000/rs6000.c (rs6000_option_override_internal): Delete
	rs6000_gen_cell_microcode code.
	(rs6000_final_prescan_insn): Delete.
	(rs6000_opt_vars): Delete the "gen-cell-microcode" and
	"warn-cell-microcode" entries.
	* config/rs6000/rs6000.h (FINAL_PRESCAN_INSN): Delete.
	* config/rs6000/rs6000.md: Delete rs6000_gen_cell_microcode tests
	throughout.  Change cc_reg_not_micro_cr0_operand to
	cc_reg_not_cr0_operand throughout.
	(*extendhi<mode>2_noload): Delete.
	* config/rs6000/rs6000.opt (mgen-cell-microcode): Replace by stub.
	(mwarn-cell-microcode): Delete.
	* doc/invoke.texi (RS/6000 and PowerPC Options): Delete
	-mgen-cell-microcode and -mwarn-cell-microcode.

gcc/testsuite/
	* gcc.target/powerpc/shift-dot.c: Delete -mgen-cell-microcode from
	dg-options.
	* gfortran.dg/pr80107.f: Delete testcase.

From-SVN: r248695