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

[Diego Caballero via llvm-commits]

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@@ -1075,6 +1099,11 @@ bool IEEEFloat::isSignificandAllOnesExceptLSB() const {
 }
 
 bool IEEEFloat::isSignificandAllZeros() const {
+  // For the E8M0 format, this is always true since there are no
+  // actual significand bits.
+  if (semantics == &semFloat8E8M0FN)
+    return true;
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dcaballe wrote:

Orthogonal to the discussion above but if we moved forward with the early exit, could we implement it using `hasExponentOnly()` to cover any other future cases?

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