[flang-commits] [flang] [flang] Fold double bessel functions on Windows. (PR #130253)

[مهدي شينون via flang-commits]

https://github.com/MehdiChinoune created https://github.com/llvm/llvm-project/pull/130253

There are no functions for `float`.
see: https://learn.microsoft.com/en-us/cpp/c-runtime-library/reference/bessel-functions-j0-j1-jn-y0-y1-yn

>From 3b0f0afe3fdcedc5979e9bf5e17f7919a3477eef Mon Sep 17 00:00:00 2001
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Date: Fri, 7 Mar 2025 07:24:43 +0100
Subject: [PATCH] [flang] Fold double bessel functions on Windows.

There are no functions for `float`.
see: https://learn.microsoft.com/en-us/cpp/c-runtime-library/reference/bessel-functions-j0-j1-jn-y0-y1-yn
---
 flang/lib/Evaluate/intrinsics-library.cpp | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/flang/lib/Evaluate/intrinsics-library.cpp b/flang/lib/Evaluate/intrinsics-library.cpp
index d2c1be65dca44..971c8d2b67e9b 100644
--- a/flang/lib/Evaluate/intrinsics-library.cpp
+++ b/flang/lib/Evaluate/intrinsics-library.cpp
@@ -559,6 +559,23 @@ struct HostRuntimeLibrary<long double, LibraryVersion::LibmExtensions> {
 #endif // HAS_FLOAT80 || HAS_LDBL128
 #endif //_POSIX_C_SOURCE >= 200112L || _XOPEN_SOURCE >= 600
 
+#ifdef _WIN32
+template <> struct HostRuntimeLibrary<double, LibraryVersion::LibmExtensions> {
+  using F = FuncPointer<double, double>;
+  using FN = FuncPointer<double, int, double>;
+  static constexpr HostRuntimeFunction table[]{
+      FolderFactory<F, F{::_j0}>::Create("bessel_j0"),
+      FolderFactory<F, F{::_j1}>::Create("bessel_j1"),
+      FolderFactory<FN, FN{::_jn}>::Create("bessel_jn"),
+      FolderFactory<F, F{::_y0}>::Create("bessel_y0"),
+      FolderFactory<F, F{::_y1}>::Create("bessel_y1"),
+      FolderFactory<FN, FN{::_yn}>::Create("bessel_yn"),
+  };
+  static constexpr HostRuntimeMap map{table};
+  static_assert(map.Verify(), "map must be sorted");
+};
+#endif
+
 /// Define pgmath description
 #if LINK_WITH_LIBPGMATH
 // Only use libpgmath for folding if it is available.