On 05/26/2016 04:36 PM, Richard Sandiford wrote:
This patch is effectively reverting a change from 1994. The reason
I think it's a hack is that store_bit_field_1 is creating a subreg
reference to one word of a field even though it has already proven that
the field spills into the following word. We then rely on the special
SUBREG handling in store_split_bit_field to ignore the extent of op0 and
look inside the SUBREG_REG regardless. I don't see any reason why we can't
pass the original op0 to store_split_bit_field instead.
Tested on aarch64-linux-gnu and x86_64-linux-gnu. OK to install?
I think it's OK. Ideally we'd know why the 1994 change was made, but
that's beyond my archaeological abiliy. The code looked very different
at the time and probably changed over the years to make this
simplification possible.
Bernd
