Hmm, maybe only keep --param=riscv-autovec-preference=none and remove other two if we think that might still useful? But anyway I have no strong opinion to keep that, I mean I am ok to remove whole --param=riscv-autovec-preference.
钟居哲 <juzhe.zh...@rivai.ai> 於 2024年2月28日 週三 21:59 寫道： > I think it makes more sense to remove --param=riscv-autovec-preference and > add -mrvv-vector-bits.... > > ------------------------------ > juzhe.zh...@rivai.ai > > > *From:* Kito Cheng <kito.ch...@gmail.com> > *Date:* 2024-02-28 20:56 > *To:* pan2.li <pan2...@intel.com> > *CC:* gcc-patches <gcc-patches@gcc.gnu.org>; juzhe.zhong > <juzhe.zh...@rivai.ai>; yanzhang.wang <yanzhang.w...@intel.com>; rdapp.gcc > <rdapp....@gmail.com>; jeffreyalaw <jeffreya...@gmail.com> > *Subject:* Re: [PATCH v3] RISC-V: Introduce gcc option mrvv-vector-bits > for RVV > Take one more look, I think this option should work and integrate with > --param=riscv-autovec-preference= since they have similar jobs but > slightly different. > > We have 3 value for --param=riscv-autovec-preference=: none, scalable > and fixed-vlmax > > -mrvv-vector-bits=scalable is work like > --param=riscv-autovec-preference=scalable and > -mrvv-vector-bits=zvl is work like > --param=riscv-autovec-preference=fixed-vlmax. > > So I think...we need to do some conflict check, like: > > -mrvv-vector-bits=zvl can't work with > --param=riscv-autovec-preference=scalable > -mrvv-vector-bits=scalable can't work with > --param=riscv-autovec-preference=fixed-vlmax > > but it may not just alias since there is some useful combinations like: > > -mrvv-vector-bits=zvl with --param=riscv-autovec-preference=none: > NO auto vectorization but intrinsic code still could benefit from the > -mrvv-vector-bits=zvl option. > > -mrvv-vector-bits=scalable with --param=riscv-autovec-preference=none > Should still work for VLS code gen, but just disable auto > vectorization per the option semantic. > > However here is something we need some fix, since > --param=riscv-autovec-preference=none still disable VLS code gen for > now, you can see some example here: > https://godbolt.org/z/fMTr3eW7K > > But I think it's really the right behavior here, this part might need > to be fixed in vls_mode_valid_p and some other places. > > > Anyway I think we need to check all use sites with RVV_FIXED_VLMAX and > RVV_SCALABLE, and need to make sure all use site of RVV_FIXED_VLMAX > also checked with RVV_VECTOR_BITS_ZVL. > > > > > -/* Return the VLEN value associated with -march. > > +static int > > +riscv_convert_vector_bits (int min_vlen) > > Not sure if we really need this function, it seems it always returns > min_vlen? > > > +{ > > + int rvv_bits = 0; > > + > > + switch (rvv_vector_bits) > > + { > > + case RVV_VECTOR_BITS_ZVL: > > + case RVV_VECTOR_BITS_SCALABLE: > > + rvv_bits = min_vlen; > > + break; > > + default: > > + gcc_unreachable (); > > + } > > + > > + return rvv_bits; > > +} > > + > > +/* Return the VLEN value associated with -march and -mwrvv-vector-bits. > > >
