CSR write could be expensive, it will flush whole pipeline in some RISC-V
core implementation…

Kito Cheng <kito.cheng@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
>>
>