[libc-commits] [libc] [libc][math][c23] Add fmodl and fmodf128 math functions. (PR #84600)

[via libc-commits]

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@@ -219,22 +158,57 @@ template <typename T> class FModDivisionInvMultHelper {
   }
 };
 
-template <typename T, class Wrapper = FModExceptionalInputHandler<T>,
-          class DivisionHelper = FModDivisionSimpleHelper<T>>
+template <typename T, typename U = typename FPBits<T>::StorageType,
+          typename DivisionHelper = FModDivisionSimpleHelper<U>>
 class FMod {
-  static_assert(cpp::is_floating_point_v<T>,
+  static_assert(cpp::is_floating_point_v<T> && cpp::is_unsigned_v<U> &&
+                    (sizeof(U) * CHAR_BIT > FPBits<T>::FRACTION_LEN),
                 "FMod instantiated with invalid type.");
 
 private:
   using FPB = FPBits<T>;
   using StorageType = typename FPB::StorageType;
 
+  LIBC_INLINE static bool pre_check(T x, T y, T &out) {
+    using FPB = fputil::FPBits<T>;
+    const T quiet_nan = FPB::quiet_nan().get_val();
+    FPB sx(x), sy(y);
+    if (LIBC_LIKELY(!sy.is_zero() && !sy.is_inf_or_nan() &&
+                    !sx.is_inf_or_nan())) {
+      return false;
+    }
+
+    if (sx.is_nan() || sy.is_nan()) {
+      if ((sx.is_nan() && !sx.is_quiet_nan()) ||
+          (sy.is_nan() && !sy.is_quiet_nan()))
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lntue wrote:

It's a bit subtle, that those 2 are not equivalent.  Line 181 means either of them is nan, and lines 182-183 means either of them is signalling nan.  I updated L182-183 to be a bit clearer.

https://github.com/llvm/llvm-project/pull/84600