The Mitsubishi D10V version of
as has a few machine dependent options.
The D10V can often execute two sub-instructions in parallel. When this option is used,
as will attempt to optimize its output by detecting when instructions can be executed in parallel.
To optimize execution performance,
as will sometimes swap the order of instructions. Normally this generates a warning. When this option is used, no warning will be generated when instructions are swapped.
as packs adjacent short instructions into a single packed instruction. --no-gstabs-packing turns instruction packing off if --gstabs is specified as well; --gstabs-packing (the default) turns instruction packing on even when --gstabs is specified.