"RegAllocPass" make apk size increase?

[hero0812]

my config file show as flollwing : { "redex" : { "passes" : [ "StripDebugInfoPass", "RegAllocPass" ] }, "StripDebugInfoPass": { "drop_all_dbg_info" : false, "drop_local_variables" : true, "drop_line_numbers" : false, "drop_src_files" : false, "use_whitelist" : false, "cls_whitelist" : [], "method_whitelist" : [], "drop_prologue_end" : true, "drop_epilogue_begin" : true, "drop_all_dbg_info_if_empty" : true }, "RegAllocPass" : { "live_range_splitting": true } }

what confuses me is when I use "RegAllocPass" , I found that apk size become larger than just use " "StripDebugInfoPass"