[llvm] [APFloat] Add APFloat support for E8M0 type (PR #107127)

[Matt Arsenault via llvm-commits]

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@@ -396,6 +404,8 @@ static inline Error createError(const Twine &Err) {
 }
 
 static constexpr inline unsigned int partCountForBits(unsigned int bits) {
+  if (bits == 0)
+    return 1;
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arsenm wrote:

Can avoid reaching here? 

https://github.com/llvm/llvm-project/pull/107127