On 3/22/20 12:30 PM, Segher Boessenkool wrote: > Hi! > > On Fri, Mar 20, 2020 at 07:42:25PM -0700, Richard Henderson via Gcc-patches > wrote: >> Duplicate all usub_*_carryinC, but use xzr for the output when we >> only require the flags output. The signed versions use sign_extend >> instead of zero_extend for combine's benefit. > > You actually use ANY_EXTEND, which makes a lot more sense :-) > > Did you see combine create a sign_extend, ever? Or do those just come > from combining other insns that already contain a sign_extend?
In the penultimate patch, for cmpti, I emit this sign_extend'ed pattern manually, so that rtl actually gets the proper description of the comparison of the high-half of the TImode variable. r~
