llvm dev - Nov 2021 - Speculative FP operation.

Hi all,

We have a  situation ,where the floating operations were hoisted
speculative from a conditional block on ARM64.

Was using the option "-mllvm --speculate-fp-insts=false" but
doesn't
have any effect from LLVM 12 .

and "-ftrapping-math" is not enabled for aarch64 .

So question to the expert ,while investigating the passes we found
that simplifyCFG does this transformation and before we investigate
and prevent this transformation .

Do the group recommend any other options here ?

Thank you
~Umesh

Hi All,

Did someone tried enabling the trapping math for the aarch64 arch ?
So that we can surpass the transformation  like below.

If not ,we would like to take it up for ARM arch.

Thank you
~Umesh

On Wed, Nov 10, 2021 at 3:00 PM Umesh Kalappa <umesh.kalappa0 at
gmail.com> wrote:
>
> Hi all,
>
> We have a  situation ,where the floating operations were hoisted
> speculative from a conditional block on ARM64.
>
> Was using the option "-mllvm --speculate-fp-insts=false" but
doesn't
> have any effect from LLVM 12 .
>
> and "-ftrapping-math" is not enabled for aarch64 .
>
> So question to the expert ,while investigating the passes we found
> that simplifyCFG does this transformation and before we investigate
> and prevent this transformation .
>
> Do the group recommend any other options here ?
>
> Thank you
> ~Umesh