re PR tree-optimization/79390 (10% performance drop in SciMark2 LU after r242550)

re PR tree-optimization/79390 (10% performance drop in SciMark2 LU after r242550)

	PR tree-optimization/79390
	* target.h (struct noce_if_info): Declare.
	* targhooks.h (default_noce_conversion_profitable_p): Declare.
	* target.def (noce_conversion_profitable_p): New target hook.
	* ifcvt.h (struct noce_if_info): New type, moved from ...
	* ifcvt.c (struct noce_if_info): ... here.
	(noce_conversion_profitable_p): Renamed to ...
	(default_noce_conversion_profitable_p): ... this.  No longer
	static nor inline.
	(noce_try_store_flag_constants, noce_try_addcc,
	noce_try_store_flag_mask, noce_try_cmove, noce_try_cmove_arith,
	noce_convert_multiple_sets): Use targetm.noce_conversion_profitable_p
	instead of noce_conversion_profitable_p.
	* config/i386/i386.c: Include ifcvt.h.
	(ix86_option_override_internal): Don't override
	PARAM_MAX_RTL_IF_CONVERSION_INSNS default.
	(ix86_noce_conversion_profitable_p): New function.
	(TARGET_NOCE_CONVERSION_PROFITABLE_P): Redefine.
	* config/i386/x86-tune.def (X86_TUNE_ONE_IF_CONV_INSN): Adjust comment.
	* doc/tm.texi.in (TARGET_NOCE_CONVERSION_PROFITABLE_P): Add.
	* doc/tm.texi: Regenerated.

	* gcc.target/i386/pr79390.c: New test.
	* gcc.dg/ifcvt-4.c: Use -mtune-ctrl=^one_if_conv_insn for i?86/x86_64.

From-SVN: r246686