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

[Matt Arsenault via llvm-commits]

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@@ -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) {
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arsenm wrote:

But why do you need to directly deal with float128? Just keep everything as APFloat in the compiler 

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