[llvm] Constant Fold Logf128 calls (PR #84501)

[Matt Arsenault via llvm-commits]

================
@@ -1688,6 +1696,16 @@ class [[nodiscard]] APInt {
     return APInt(sizeof(float) * CHAR_BIT, llvm::bit_cast<uint32_t>(V));
   }
 
+#ifdef __FLOAT128__
+  static APInt longDoubleToBits(float128 V) {
----------------
arsenm wrote:

I don't think APInt/APFloat should be exposing APIs that are only conditionally available. That kind of defeats the point of using them 

https://github.com/llvm/llvm-project/pull/84501