CSR write could be expensive, it will flush whole pipeline in some RISC-V core implementation…
Kito Cheng <kito.ch...@gmail.com>於 2023年7月26日 週三，21:57寫道： > Sorry for late ack on the LLVM part, I can say they are did the same > model/semantics, it done by our team member too, and I have regular meeting > with that guy :P > > Robin Dapp via Gcc-patches <gcc-patches@gcc.gnu.org>於 2023年7月26日 > 週三，21:47寫道： > >> > current llvm didn't do any pre optimization. They always >> > backup+restore for each rounding mode intrinsic >> >> I see. There is still the option of lazily restoring the >> (entry) FRM before a function call but not read the FRM >> after every call. Do we have any data on how good or bad the >> mode-switching LCM works when we explicitly backup and restore >> for each intrinsic? >> >> Regards >> Robin >> >
