[llvm] [APFloat] add power (PR #122889)

[Jakub Kuderski via llvm-commits]

================
@@ -1536,6 +1536,27 @@ inline APFloat abs(APFloat X) {
   return X;
 }
 
+/// Returns X^N for N >= 0.
+/// Returns X^N for N >= 0.
+inline APFloat pow(const APFloat &X, const int &N) {
----------------
kuhar wrote:

I don't see what we gain by passing N as a const reference

```suggestion
inline APFloat pow(const APFloat &X, int N) {
```

https://github.com/llvm/llvm-project/pull/122889