re PR target/1532 (-O3 generates (obviously) redundant tests and jumps)

re PR target/1532 (-O3 generates (obviously) redundant tests and jumps)

	PR gcc/1532
	* cse.c (cse_change_cc_mode): New static function.
	(cse_change_cc_mode_insns, cse_cc_succs): Likewise.
	(cse_condition_code_reg): New function.
	* rtl.h (cse_condition_code_reg): Declare.
	* toplev.c (rest_of_handle_cse2): Call cse_condition_code_reg.
	* target.h (struct gcc_target): Add fixed_condition_code_regs and
	cc_modes_compatible.
	* target-def.h (TARGET_FIXED_CONDITION_CODE_REGS): Define.
	(TARGET_CC_MODES_COMPATIBLE): Define.
	(TARGET_INITIALIZER): Add new initializers.
	* targhooks.c (default_cc_modes_compatible): New function.
	* targhooks.c (default_cc_modes_compatible): Declare.
	* hooks.c (hook_bool_intp_intp_false): New function.
	* hooks.h (hook_bool_intp_intp_false): Declare.
	* config/i386/i386.c (TARGET_FIXED_CONDITION_CODE_REGS): Define.
	(TARGET_CC_MODES_COMPATIBLE): Define.
	(ix86_fixed_condition_code_regs): New static function.
	(ix86_cc_modes_compatible): Likewise.
	* doc/tm.texi (Condition Code): Document new hooks.

From-SVN: r76454