From f68ff1ac1ccc233cd0e70c707a9e9dd5a0f71ee6 Mon Sep 17 00:00:00 2001
From: Dimitry Andric <dim@FreeBSD.org>
Date: Sat, 2 Nov 2019 16:59:53 +0000
Subject: [PATCH] Add __isnan()/__isnanf() aliases for compatibility with glibc
 and CUDA

Even though clang comes with a number of internal CUDA wrapper headers,
compiling sample CUDA programs will result in errors similar to:

In file included from <built-in>:1:
In file included from /usr/lib/clang/9.0.0/include/__clang_cuda_runtime_wrapper.h:204:
/usr/home/arr/cuda/var/cuda-repo-10-0-local-10.0.130-410.48/usr/local/cuda-10.0//include/crt/math_functions.hpp:2910:7: error: no matching function for call to '__isnan'
  if (__isnan(a)) {
      ^~~~~~~
/usr/lib/clang/9.0.0/include/__clang_cuda_device_functions.h:460:16: note: candidate function not viable: call to __device__ function from __host__ function
__DEVICE__ int __isnan(double __a) { return __nv_isnand(__a); }
               ^

CUDA expects __isnan() and __isnanf() declarations to be available,
which are glibc specific extensions, equivalent to the regular isnan()
and isnanf().

To provide these, define __isnan() and __isnanf() as aliases of the
already existing static inline functions __inline_isnan() and
__inline_isnanf() from math.h.

Reported by:	arrowd
PR:		241550
MFC after:	1 week
---
 lib/libc/gen/isnan.c   | 7 +++++++
 lib/msun/src/math.h    | 6 ++++++
 lib/msun/src/s_isnan.c | 6 ++++++
 3 files changed, 19 insertions(+)

diff --git a/lib/libc/gen/isnan.c b/lib/libc/gen/isnan.c
index e17d915e0ad3..ea84c7ebe403 100644
--- a/lib/libc/gen/isnan.c
+++ b/lib/libc/gen/isnan.c
@@ -43,6 +43,13 @@
  */
 
 #ifdef PIC
+/*
+ * Because math.h defines __isnan and __isnanf as aliases for compatibility with
+ * glibc and CUDA, we have to undefine them here to avoid redefinition errors.
+ */
+#undef __isnan
+#undef __isnanf
+
 __weak_reference(__isnan, isnan);
 __weak_reference(__isnanf, isnanf);
 
diff --git a/lib/msun/src/math.h b/lib/msun/src/math.h
index a8f45544c475..6ce45cbb5280 100644
--- a/lib/msun/src/math.h
+++ b/lib/msun/src/math.h
@@ -214,6 +214,12 @@ __inline_isnanl(__const long double __x)
 	return (__x != __x);
 }
 
+/*
+ * Define the following aliases, for compatibility with glibc and CUDA.
+ */
+#define __isnan __inline_isnan
+#define __isnanf __inline_isnanf
+
 /*
  * Version 2 of the Single UNIX Specification (UNIX98) defined isnan() and
  * isinf() as functions taking double.  C99, and the subsequent POSIX revisions
diff --git a/lib/msun/src/s_isnan.c b/lib/msun/src/s_isnan.c
index 249c00615748..ea3c8db67da6 100644
--- a/lib/msun/src/s_isnan.c
+++ b/lib/msun/src/s_isnan.c
@@ -45,6 +45,12 @@ isnan(double d)
 }
 #endif /* !PIC */
 
+/*
+ * Because math.h defines __isnanf as an alias for compatibility with glibc and
+ * CUDA, we have to undefine it here to avoid redefinition errors.
+ */
+#undef __isnanf
+
 int
 __isnanf(float f)
 {