https://github.com/bassiounix created https://github.com/llvm/llvm-project/pull/224690
Now that __builtin_exp and __builtin_expf are constant-evaluable in clang (#199808), mark libc++'s float, double, and integral-promoting overloads of __math::exp as _LIBCPP_CONSTEXPR_SINCE_CXX23. The long double overload stays non-constexpr because __builtin_expl is not constant-evaluable yet. Add constexpr coverage for std::exp and std::expf to the clang-specific constexpr <cmath> test. Co-Authored-By: Claude Fable 5.1 <[email protected]> --- <sub>Stack created with <a href="https://github.com/github/gh-stack";>GitHub Stacks CLI</a> • <a href="https://gh.io/stacks-feedback";>Give Feedback 💬</a></sub> >From 34a4380f2a3984642032c4de9e51d605dbc38654 Mon Sep 17 00:00:00 2001 From: bassiounix <[email protected]> Date: Fri, 18 Sep 2026 20:18:25 +0300 Subject: [PATCH] [libc++] Make std::exp constexpr for float and double since C++23 Now that __builtin_exp and __builtin_expf are constant-evaluable in clang (#199808), mark libc++'s float, double, and integral-promoting overloads of __math::exp as _LIBCPP_CONSTEXPR_SINCE_CXX23. The long double overload stays non-constexpr because __builtin_expl is not constant-evaluable yet. Add constexpr coverage for std::exp and std::expf to the clang-specific constexpr <cmath> test. Co-Authored-By: Claude Fable 5.1 <[email protected]> --- libcxx/include/__math/exponential_functions.h | 8 +++++--- .../libcxx/numerics/c.math/constexpr-cxx23-clang.pass.cpp | 4 ++++ 2 files changed, 9 insertions(+), 3 deletions(-) diff --git a/libcxx/include/__math/exponential_functions.h b/libcxx/include/__math/exponential_functions.h index 09930b7819e23..1da3cfa2ea38d 100644 --- a/libcxx/include/__math/exponential_functions.h +++ b/libcxx/include/__math/exponential_functions.h @@ -26,17 +26,19 @@ namespace __math { // exp -inline _LIBCPP_HIDE_FROM_ABI float exp(float __x) _NOEXCEPT { return __builtin_expf(__x); } +inline _LIBCPP_CONSTEXPR_SINCE_CXX23 _LIBCPP_HIDE_FROM_ABI float exp(float __x) _NOEXCEPT { + return __builtin_expf(__x); +} template <class = int> -_LIBCPP_HIDE_FROM_ABI double exp(double __x) _NOEXCEPT { +_LIBCPP_CONSTEXPR_SINCE_CXX23 _LIBCPP_HIDE_FROM_ABI double exp(double __x) _NOEXCEPT { return __builtin_exp(__x); } inline _LIBCPP_HIDE_FROM_ABI long double exp(long double __x) _NOEXCEPT { return __builtin_expl(__x); } template <class _A1, __enable_if_t<is_integral<_A1>::value, int> = 0> -inline _LIBCPP_HIDE_FROM_ABI double exp(_A1 __x) _NOEXCEPT { +inline _LIBCPP_CONSTEXPR_SINCE_CXX23 _LIBCPP_HIDE_FROM_ABI double exp(_A1 __x) _NOEXCEPT { return __builtin_exp((double)__x); } diff --git a/libcxx/test/libcxx/numerics/c.math/constexpr-cxx23-clang.pass.cpp b/libcxx/test/libcxx/numerics/c.math/constexpr-cxx23-clang.pass.cpp index beca4907284ad..b9e0afab6349e 100644 --- a/libcxx/test/libcxx/numerics/c.math/constexpr-cxx23-clang.pass.cpp +++ b/libcxx/test/libcxx/numerics/c.math/constexpr-cxx23-clang.pass.cpp @@ -207,6 +207,10 @@ int main(int, char**) { ASSERT_CONSTEXPR_CXX23(std::fpclassify(-1.0) == FP_NORMAL); ASSERT_CONSTEXPR_CXX23(std::fpclassify(-1.0L) == FP_NORMAL); + ASSERT_CONSTEXPR_CXX23(std::exp(0.0f) == 1.0f); + ASSERT_CONSTEXPR_CXX23(std::exp(0.0) == 1.0); + ASSERT_CONSTEXPR_CXX23(std::expf(0.0f) == 1.0f); + ASSERT_CONSTEXPR_CXX23(std::isfinite(-1.0f) == 1); ASSERT_CONSTEXPR_CXX23(std::isfinite(-1.0) == 1); ASSERT_CONSTEXPR_CXX23(std::isfinite(-1.0L) == 1); _______________________________________________ llvm-branch-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-branch-commits
