[flang] Fold double bessel functions on Windows.

[MehdiChinoune]

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

[llvmbot]

@llvm/pr-subscribers-flang-semantics

Author: مهدي شينون (Mehdi Chinoune) (MehdiChinoune)

Changes

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

---

Full diff: https://github.com/llvm/llvm-project/pull/130253.diff

1 Files Affected:

• (modified) flang/lib/Evaluate/intrinsics-library.cpp (+17)

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.

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[MehdiChinoune]

ping!

[jeanPerier]

Not familiar with windows, but change looks good, thanks.

[MehdiChinoune]

I don't have commit access, could someone push changes, please.

[DavidTruby]

LGTM too so I will merge, thanks!