[clang] [llvm] [APFloat] Add APFloat support for FP6 data types (PR #94735)

[Jakub Kuderski via cfe-commits]

================
@@ -68,6 +68,10 @@ enum class fltNonfiniteBehavior {
   // `fltNanEncoding` enum. We treat all NaNs as quiet, as the available
   // encodings do not distinguish between signalling and quiet NaN.
   NanOnly,
+
+  // This behavior is present in Float6E3M2FN and Float6E2M3FN types.
+  // There is no representation for Inf or NaN.
+  NoNanInf,
----------------
kuhar wrote:

nit:
```suggestion
  // This behavior is present in Float6E3M2FN and Float6E2M3FN types,
  // which do not support Inf or NaN values.
  NoNanInf,
```
also, is there a standard name for such FP types? Maybe `Finite` or would that be too overloaded?


https://github.com/llvm/llvm-project/pull/94735