[PATCH v3 4/7] ifcvt/optabs: Allow using a CC comparison for emit_conditional_move.

[Robin Dapp]

Posting the ChangeLog before pushing.

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gcc/ChangeLog:

	* rtl.h (struct rtx_comparison): New struct that holds an rtx
	comparison.
	* config/rs6000/rs6000.c (rs6000_emit_minmax): Use struct instead of
        single parameters.
	(rs6000_emit_swsqrt): Likewise.
	* expmed.c (expand_sdiv_pow2): Likewise.
	(emit_store_flag): Likewise.
	* expr.c (expand_cond_expr_using_cmove): Likewise.
	(expand_expr_real_2): Likewise.
	* ifcvt.c (noce_emit_cmove): Add compare and reversed compare
	parameters and allow to call directly without going through
	preparation steps.
	* optabs.c (emit_conditional_move_1): New function.
	(expand_doubleword_shift_condmove): Use struct.
	(emit_conditional_move): Use struct.
	* optabs.h (emit_conditional_move): Use struct.