[libc-commits] [llvm] [libc] [libc][math] Implement nexttoward functions (PR #72763)

[Nick Desaulniers via libc-commits]

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@@ -169,8 +171,50 @@ LIBC_INLINE T nextafter(T from, T to) {
     int_val = (to_bits.uintval() & sign_mask) + UIntType(1);
   }
 
+  UIntType exponent_bits = int_val & FloatProperties<T>::EXPONENT_MASK;
+  if (exponent_bits == UIntType(0))
+    raise_except_if_required(FE_UNDERFLOW | FE_INEXACT);
+  else if (exponent_bits == FloatProperties<T>::EXPONENT_MASK)
+    raise_except_if_required(FE_OVERFLOW | FE_INEXACT);
+
+  return cpp::bit_cast<T>(int_val);
+}
+
+template <typename T>
+LIBC_INLINE cpp::enable_if_t<cpp::is_floating_point_v<T>, T>
+nexttoward(T from, long double to) {
+  FPBits<T> from_bits(from);
+  if (from_bits.is_nan())
+    return from;
+
+  FPBits<long double> to_bits(to);
+  if (to_bits.is_nan())
+    return to;
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nickdesaulniers wrote:

ah, thanks, slightly behind!

https://github.com/llvm/llvm-project/pull/72763