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
>