From da0cd38267282241a92d3b6e7ce11f524276e075 Mon Sep 17 00:00:00 2001
From: Robin Caloudis <robin.caloudis@gmx.de>
Date: Thu, 18 Jul 2024 15:01:09 +0200
Subject: [PATCH] [libc++] Fix acceptance of convertible-to-{float,double,long
 double} in std::isfinite() (#98841)

Closes https://github.com/llvm/llvm-project/issues/98816.
---
 libcxx/include/__math/traits.h                    | 12 ++++++++++++
 libcxx/test/std/numerics/c.math/isfinite.pass.cpp | 12 ++++++++++++
 2 files changed, 24 insertions(+)

diff --git a/libcxx/include/__math/traits.h b/libcxx/include/__math/traits.h
index a4482667975576c..27ec52ecef022e9 100644
--- a/libcxx/include/__math/traits.h
+++ b/libcxx/include/__math/traits.h
@@ -55,6 +55,18 @@ _LIBCPP_NODISCARD _LIBCPP_CONSTEXPR_SINCE_CXX23 _LIBCPP_HIDE_FROM_ABI bool isfin
   return true;
 }
 
+_LIBCPP_NODISCARD inline _LIBCPP_CONSTEXPR_SINCE_CXX23 _LIBCPP_HIDE_FROM_ABI bool isfinite(float __x) _NOEXCEPT {
+  return __builtin_isfinite(__x);
+}
+
+_LIBCPP_NODISCARD inline _LIBCPP_CONSTEXPR_SINCE_CXX23 _LIBCPP_HIDE_FROM_ABI bool isfinite(double __x) _NOEXCEPT {
+  return __builtin_isfinite(__x);
+}
+
+_LIBCPP_NODISCARD inline _LIBCPP_CONSTEXPR_SINCE_CXX23 _LIBCPP_HIDE_FROM_ABI bool isfinite(long double __x) _NOEXCEPT {
+  return __builtin_isfinite(__x);
+}
+
 // isinf
 
 template <class _A1, __enable_if_t<is_arithmetic<_A1>::value && numeric_limits<_A1>::has_infinity, int> = 0>
diff --git a/libcxx/test/std/numerics/c.math/isfinite.pass.cpp b/libcxx/test/std/numerics/c.math/isfinite.pass.cpp
index 6bbc3aaac6d130f..3d5be616343343e 100644
--- a/libcxx/test/std/numerics/c.math/isfinite.pass.cpp
+++ b/libcxx/test/std/numerics/c.math/isfinite.pass.cpp
@@ -62,9 +62,21 @@ struct TestInt {
   }
 };
 
+template <typename T>
+struct ConvertibleTo {
+  operator T() const { return T(); }
+};
+
 int main(int, char**) {
   types::for_each(types::floating_point_types(), TestFloat());
   types::for_each(types::integral_types(), TestInt());
 
+  // Make sure we can call `std::isfinite` with convertible types
+  {
+    assert(std::isfinite(ConvertibleTo<float>()));
+    assert(std::isfinite(ConvertibleTo<double>()));
+    assert(std::isfinite(ConvertibleTo<long double>()));
+  }
+
   return 0;
 }