[libc] Add `lgamma` and `lgamma_r` stubs for the GPU (#102019)

Summary:
These functions are used by the <random> implementation in libc++ and
cause a lot of tests to fail. For now we provide these through the
vendor abstraction until we have a real version. The NVPTX version
doesn't even update the output correctly so these are just temporary.

1 files changed, 24 insertions, 0 deletions

diff --git a/libc/src/math/amdgpu/lgamma_r.cpp b/libc/src/math/amdgpu/lgamma_r.cpp
new file mode 100644
index 000000000000..0a79988d66e3
--- /dev/null
+++ b/libc/src/math/amdgpu/lgamma_r.cpp
@@ -0,0 +1,24 @@
+//===-- Implementation of the lgamma_r function for GPU -------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "src/math/lgamma_r.h"
+#include "src/__support/common.h"
+
+#include "declarations.h"
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+LLVM_LIBC_FUNCTION(double, lgamma_r, (double x, int *signp)) {
+  int tmp = *signp;
+  double r = __ocml_lgamma_r_f64(x, (gpu::Private<int> *)&tmp);
+  *signp = tmp;
+  return r;
+}
+
+} // namespace LIBC_NAMESPACE_DECL