* function.c: Include hash.h.
	(insns_for_mem_entry): New struct.
	(put_reg_into_stack): Take an optional hash-table mapping MEMs to
	the INSNs that use them.
	(fixup_var_refs): Likewise.
	(put_addressof_into_stack): Likewise.
	(purge_addressof_1): Likewise.  Keep the hash-table up to date if
	we add new instructions.
	(fixup_var_refs_insns): Use it to avoid searching the entire
	instruction chain.
	(insns_for_mem_newfunc): New function.
	(insns_for_mem_comp): Likewise.
	(insns_for_mem_walk): Likewise.
	(compute_insns_for_mem): Likewise.
	(pop_function_context_from): Pass NULL for the hash-table.
	(put_var_into_stack): Likewise.
	(gen_mem_addressof): Likewise.
	(flush_addressof): Likewise.
	(purge_addressof): Call compute_insns_for_mem to pre-compute the
	hash table.
	* Makefile.in (OBJS): Include hash.o.
	(function.o): Depend on hash.h.
	* Makefile.in (OBJS): Don't mention hash.o.
	(OBJDEPS): Likewise.

From-SVN: r25922