PR tree-optimization/47679
	* Makefile.in (OBJS): Add tree-ssa-phionlycprop.o
	* tree-ssa-dom.c: Remove unnecessary header includes.
	(remove_stmt_or_phi): Moved from here into tree-ssa-phionlycprop.c
	(get_rhs_or_phi_arg, get_lhs_or_phi_result): Likewise.
	(propagate_rhs_into_lhs, eliminate_const_or_copy): Likewise.
	(eliminate_degenerate_phis_1, pass_phi_only_cprop): Likewise.
	(pass_phi_only_cprop::execute): Likewise.
	(make_pass_phi_only_cprop): Likewise.
	* tree-ssa-phionlycprop.c: New file with moved code.  Eliminate
	uses of file scoped statics by passing the required objects
	as parameters wherever needed.

From-SVN: r227908