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

[Matt Arsenault via llvm-commits]

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@@ -4574,7 +4671,11 @@ IEEEFloat::opStatus IEEEFloat::next(bool nextDown) {
       // the integral bit to 1, and increment the exponent. If we have a
       // denormal always increment since moving denormals and the numbers in the
       // smallest normal binade have the same exponent in our representation.
-      bool WillCrossBinadeBoundary = !isDenormal() && isSignificandAllOnes();
+      // If there are only exponents, any increment always crosses the
+      // BinadeBoundary.
+      bool WillCrossBinadeBoundary =
+          !isDenormal() &&
+          (APFloat::hasSignificand(*semantics) ? isSignificandAllOnes() : true);
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arsenm wrote:

this is an and 

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