On 09/09/2022 13:20, Tobias Burnus wrote:
However, the pre-existing 'sqrt' problem still is real. It also applies
to reverse sqrt ("v_rsq"), but that's for whatever reason not used for GCN.
This patch now adds a commandline flag - off by default - to choose
whether this behavior is wanted. I did use the same name as aarch64,
https://gcc.gnu.org/onlinedocs/gcc/AArch64-Options.html#index-mlow-precision-sqrt (the latter also has -mlow-precision-recip-sqrt, which is not (yet) sensible for GCN.)
This patch was manually tested for all combinations and I also looked at
insn-recog.cc, given that it is my first .md patch – it it seems to work
fine.
OK for mainline – or are there comments or more suggestions? I also
included some word for the release notes.
No, thank you.
I don't see any value in adding an option no one cares about (but we
still have to maintain and test).
I think it will make sense to drop the double-precision insn definition
and fall back to libm in that case.
Kwok is currently reviewing all the libm functions and can probably
include this one.
Andrew
