[CUDA] Improve handling of math functions.

Summary:
A bunch of related changes here to our CUDA math headers.

- The second arg to nexttoward is a double (well, technically, long
  double, but we don't have that), not a float.

- Add a forward-declare of llround(float), which is defined in the CUDA
  headers.  We need this for the same reason we need most of the other
  forward-declares: To prevent a constexpr function in our standard
  library from becoming host+device.

- Add nexttowardf implementation.

- Pull "foobarf" functions defined by the CUDA headers in the global
  namespace into namespace std.  This lets you do e.g. std::sinf.

- Add overloads for math functions accepting integer types.  This lets
  you do e.g. std::sin(0) without having an ambiguity between the
  overload that takes a float and the one that takes a double.

With these changes, we pass testcases derived from libc++ for cmath and
math.h.  We can check these testcases in to the test-suite once support
for CUDA lands there.

Reviewers: tra

Subscribers: cfe-commits

Differential Revision: https://reviews.llvm.org/D23627

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@279140 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 4 insertions, 1 deletions

diff --git a/lib/Headers/__clang_cuda_math_forward_declares.h b/lib/Headers/__clang_cuda_math_forward_declares.h
index 3f2834d950..0a605e1956 100644
--- a/lib/Headers/__clang_cuda_math_forward_declares.h
+++ b/lib/Headers/__clang_cuda_math_forward_declares.h
@@ -140,6 +140,7 @@ __DEVICE__ long lrint(double);
 __DEVICE__ long lrint(float);
 __DEVICE__ long lround(double);
 __DEVICE__ long lround(float);
+__DEVICE__ long long llround(float); // No llround(double).
 __DEVICE__ double modf(double, double *);
 __DEVICE__ float modf(float, float *);
 __DEVICE__ double nan(const char *);
@@ -149,7 +150,8 @@ __DEVICE__ float nearbyint(float);
 __DEVICE__ double nextafter(double, double);
 __DEVICE__ float nextafter(float, float);
 __DEVICE__ double nexttoward(double, double);
-__DEVICE__ float nexttoward(float, float);
+__DEVICE__ float nexttoward(float, double);
+__DEVICE__ float nexttowardf(float, double);
 __DEVICE__ double pow(double, double);
 __DEVICE__ double pow(double, int);
 __DEVICE__ float pow(float, float);
@@ -235,6 +237,7 @@ using ::log2;
 using ::logb;
 using ::lrint;
 using ::lround;
+using ::llround;
 using ::modf;
 using ::nan;
 using ::nanf;