Simplify sinh(x) / cosh(x) -> tanh(x) with fast-math

[k-arrows]

It seems that the simplification sin(x) / cos(x) -> tan(x) has been already implemented, but the same applies for hyperbolic function(s).

https://godbolt.org/z/WqYfKxr7K

For those who are interested in floating-point arithmetic optimization, I think this can be added to #34959.

Hey is anyone working on this ? If not could someone assign this to me ?

[dc03]

No one's replied till now (5 days since issue filing), so I'll assume no one has picked this up.

[arsenm]

#77799 also related

Thanks for assigning me, I will look into this as soon as possible

I am almost done with this but there is one thing I can't quite figure out. I used replaceInstUsesWith to replace the div Instruction with a call Instruction to tanh. This does not replace the calls to sinh and cosh but when looking at the optimization of sin/cos it seems to replace the calls to sin and cos, why is this and how can I delete the calls to sinh and cosh ?
Any help would be appreciated.

[arsenm]

it seems to replace the calls tosinandcos, why is this and how can I delete the calls to sinhandcosh` ? Any help would be appreciated.

The replaceInstUsesWith only replaces the uses, leaving behind the dead call instructions. You need to separately erase them