[hip] Fix `<complex>` compilation on Windows with VS2019.

[hliao]

Fix typo.

[MaskRay]

In your commit the message does not include Reviewed by:. Many people agree that both Reviewed by: & Differential Revision: should be present. The Reviewed by: list indicates people who acknowledged the patch. (The Reviewers: list does not necessarily mean all the people on the list have acknowledged the patch so Reviewers: is mostly useless.)

arc amend can fetch the Phabricator summary and amend the local description.

You can install llvm/utils/git/pre-push.py to prevent accidental Summary:, Reviewers:, Subscribers: and Tags: in the presence of Differential Revision:.

clang/lib/Headers/__clang_hip_cmath.h

 #ifdef _GLIBCXX_BEGIN_NAMESPACE_VERSION
 _GLIBCXX_END_NAMESPACE_VERSION
 #endif
 } // namespace std
 #endif
 
 // Define device-side math functions from <ymath.h> on MSVC.
 #if defined(_MSC_VER)
+
+// Before VS2019, `<ymath.h>` is also included in `<limits>` and other headers.
+// But, from VS2019, it's only included in `<complex>`. Need to include
+// `<ymath.h>` here to ensure C functions declared there won't be markded as
+// `__host__` and `__device__` through `<complex>` wrapper.
+#include <ymath.h>
+
 #if defined(__cplusplus)
 extern "C" {
 #endif // defined(__cplusplus)
 __DEVICE__ __attribute__((overloadable)) double _Cosh(double x, double y) {
   return cosh(x) * y;
 }
 __DEVICE__ __attribute__((overloadable)) float _FCosh(float x, float y) {
   return coshf(x) * y;