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

[Nick Desaulniers via libc-commits]

================
@@ -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()))
+        fputil::raise_except_if_required(FE_INVALID);
+      out = quiet_nan;
+      return true;
+    }
+
+    if (sx.is_inf() || sy.is_zero()) {
+      fputil::raise_except_if_required(FE_INVALID);
+      fputil::set_errno_if_required(EDOM);
+      out = quiet_nan;
+      return true;
+    }
+
+    if (sy.is_inf()) {
+      out = x;
+      return true;
+    }
+
+    // case where x == 0
+    out = x;
+    return true;
----------------
nickdesaulniers wrote:

Either sides of this branch look the same to me. Intentional?

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