https://gcc.gnu.org/bugzilla/show_bug.cgi?id=121947
Hongtao Liu <liuhongt at gcc dot gnu.org> changed:
What |Removed |Added
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CC| |liuhongt at gcc dot gnu.org
--- Comment #1 from Hongtao Liu <liuhongt at gcc dot gnu.org> ---
---------------Quote from [1].---------------------------
> > No, the approach is wrong. You have to solve output clearing on RTL
> > level, please look at how e.g. tzcnt false dep is solved:
>
> Actually we have considered such approach before, but we found we need
> to break original define_insn to remove the mask/rounding subst,
> since define_split could not adopt subst, and that would add 6 more
> define_insn_and_split and 4 define_insn for each instruction. We think
> such approach would introduce too much redundant code.
>
> Do you think the code size increment is acceptable?
Also that 100+ more patterns increases maintenance effort. If we split
them at epilogue_complete stage,
it seems not much difference to put it under output template...
------------------Quote end------------------------
This is the reason we didn't choose "the splitter way" at the begining.
[1] https://gcc.gnu.org/pipermail/gcc-patches/2022-January/588436.html
