* local-alloc.c (function_invariant_p): New function.
	(update_equiv_regs): Use function_invariant_p instead of CONSTANT_P
	to decide if an equivalence should be recorded.
	* reload1.c (num_eliminable_invariants): New static variable.
	(reload): Set it.  Use function_invariant_p instead of CONSTANT_P
	to decide if an equivalence should be recorded.
	Unshare PLUS.
	(calculate_needs_all_insns): Skip insns that only set an equivalence.
	Take num_eliminable_invariants into account when deciding
	if register elimination should be done.
	(reload_as_needed): Take num_eliminable_invariants into account
	when deciding if register elimination should be done.
	(eliminate_regs): Handle non-constant reg_equiv_constant.
	* rtl.h (function_invariant_p): Declare.

From-SVN: r24026