* fwprop.c (try_fwprop_subst): Use set_unique_reg_note
	to add the REG_EQ* note.
	* see.c (see_merge_one_use_extension): Likewise.
	* local-alloc.c (update_equiv_regs): Likewise.  Also don't
	turn REG_EQUAL notes into REG_EQUIV notes if the target
	register may have more than one set.
	* function.c (assign_parm_setup_reg): Use set_unique_reg_note.
	* gcse.c (try_replace_reg): Likewise.
	* alias.c (init_alias_analysis): Use find_reg_equal_equiv_note.
	* calls.c (fixup_tail_calls): Likewise.  Abort if there is
	more than one REG_EQUIV note.
	* reload1.c (gen_reload): Use set_unique_reg_note.

From-SVN: r121821