re PR rtl-optimization/89965 (wrong code with -O -mtune=nano-x2 -fcaller-saves -fexpensive-optimizations -fno-tree-dce -fno-tree-ter)

	PR rtl-optimization/89965
	* dce.c (sp_based_mem_offset): New function.
	(find_call_stack_args): Use sp_based_mem_offset.

From-SVN: r270278