Ping for some "make more use of ..." patches

[Jeff Law]

On 09/18/2017 10:29 AM, Richard Sandiford wrote:
> Ping for some minor cleanups that help with the move to variable-length
> modes.  Segher has approved the combine.c parts (thanks).
> 
> https://gcc.gnu.org/ml/gcc-patches/2017-08/msg01339.html
> Make more use of HWI_COMPUTABLE_MODE_P
OK.

> 
> https://gcc.gnu.org/ml/gcc-patches/2017-08/msg01452.html
> Make more use of read_modify_subreg_p
> 
> https://gcc.gnu.org/ml/gcc-patches/2017-08/msg01343.html
> Make more use of subreg_lowpart_offset
> 
> https://gcc.gnu.org/ml/gcc-patches/2017-08/msg01344.html
> Make more use of subreg_size_lowpart_offset
> 
> https://gcc.gnu.org/ml/gcc-patches/2017-08/msg01345.html
> Make more use of byte_lowpart_offset
I think I've covered the rest over the last couple days.

jeff