LLVM mangling error with powi

[chalcolith]

The following program:

actor Main
  new create(env: Env) =>
    let a: F64 = 3.14
    let b: F64 = a.powi(-2)
    env.out.print("B is now " + b.string())

Gives LLVM errors when compiling on Linux:

0.58.0-a161b7c [release]
Compiled with: LLVM 15.0.7 -- Clang-16.0.6-x86_64
Defaults: pic=true
Intrinsic name not mangled correctly for type arguments! Should be: llvm.powi.f64.i32
ptr @llvm.powi.f64
Intrinsic name not mangled correctly for type arguments! Should be: llvm.powi.f64.i32
ptr @llvm.powi.f64
Error:
Module verification failed: Intrinsic name not mangled correctly for type arguments! Should be: llvm.powi.f64.i32
ptr @llvm.powi.f64
Intrinsic name not mangled correctly for type arguments! Should be: llvm.powi.f64.i32
ptr @llvm.powi.f64

    Info:
Please file an issue ticket. Use --noverify to bypass this error.

[SeanTAllen]

This is a very simple fix, I'll open a fix for it after I verify that it fails with a test, but there might be others we should review for.

[chalcolith]

I already have a fix.

[SeanTAllen]

@chalcolith can you get the f32 powi as well?

[chalcolith]

Yes