Ahhh. Thanks kito. Can you give more comments about Robin's opinion that he want to change into "fixed" vs "varying" or "fixed vector size" vs "dynamic vector size" ? I am Ok with any of them. juzhe.zhong@rivai.ai From: Kito Cheng Date: 2023-04-20 17:31 To: juzhe.zhong@rivai.ai CC: Robin Dapp; gcc-patches; palmer; jeffreyalaw Subject: Re: Re: [PATCH 2/3 V2] RISC-V: Enable basic auto-vectorization for RVV On Thu, Apr 20, 2023 at 5:07 PM juzhe.zhong@rivai.ai wrote: > > >> With --param=riscv-autovec-preference=fixed-vlmax, however, the output is > >> reasonable. BTW please use --param instead of -param in the description to > >> avoid confusion. > >>Now the patches don't explicitly note that they only work for certain marchs, > >>configurations or so but they certainly shouldn't introduce ICEs for > >>unsupported configurations. > > Address comments. And fix that soon. Thank you so much. > > >>Are the "fixed-vlmax" vs "scalable" names based on ARM's SVE? I haven't thought > >>this through but I think I'd prefer "fixed" vs "varying" or more explicitly > >>"fixed vector size" vs "dynamic vector size". Certainly room for discussion here. > >>What about the -mriscv-vector-bits=... (which would be vlen in v-spec parlance) > >>from your "rvv-next" branch? Is this orthogonal to the new parameter here? Are you > >>thinking of introducing this as well? > > The current compile options are suggested by Kito. They are internal GCC compile option. > I was trying to add -mriscv-vector-bits-...., However, it was objected by LLVM community. > https://github.com/riscv-non-isa/riscv-toolchain-conventions/issues/33 Wait, -mriscv-vector-bits= isn't objected by LLVM, what they objected to is lmul option. LLVM community has try to implmenat that: https://reviews.llvm.org/D145088 But personally I would prefer not to rush to implement that feature on upstream, we could implement that and have more conversion with LLVM community and then document that into https://github.com/riscv-non-isa/rvv-intrinsic-doc or https://github.com/riscv-non-isa/riscv-toolchain-conventions > I think in case of compile options, Kito may give more comments since he is the RISC-V ABI and convention maintainer. > I develop this patch following his order.