"Richard Earnshaw (lists)" <richard.earns...@arm.com> writes: > On 02/04/2020 19:53, Richard Henderson via Gcc-patches wrote: >> This is attacking case 3 of PR 94174. >> >> In v2, I unify the various subtract-with-borrow and add-with-carry >> patterns that also output flags with unspecs. As suggested by >> Richard Sandiford during review of v1. It does seem cleaner. >> > > Really? I didn't need to use any unspecs for the Arm version of this. > > R.
See https://gcc.gnu.org/pipermail/gcc-patches/2020-April/543063.html (including quoted context) for how we got here. The same problem affects the existing aarch64 patterns like *usub<GPI:mode>3_carryinC. Although that pattern avoids unspecs, the compare:CC doesn't seem to be correct. Richard
