[CUDA] Support <complex> and std::min/max on the device.

Summary:
We do this by wrapping <complex> and <algorithm>.

Tests are in the test-suite.

Reviewers: tra

Subscribers: jhen, beanz, cfe-commits, mgorny

Differential Revision: https://reviews.llvm.org/D24979

llvm-svn: 283680

1 files changed, 96 insertions, 0 deletions

diff --git a/clang/lib/Headers/cuda_wrappers/algorithm b/clang/lib/Headers/cuda_wrappers/algorithm
new file mode 100644
index 00000000000..95d9beb73c6
--- /dev/null
+++ b/clang/lib/Headers/cuda_wrappers/algorithm
@@ -0,0 +1,96 @@
+/*===---- complex - CUDA wrapper for <algorithm> ----------------------------===
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ *
+ *===-----------------------------------------------------------------------===
+ */
+
+#ifndef __CLANG_CUDA_WRAPPERS_ALGORITHM
+#define __CLANG_CUDA_WRAPPERS_ALGORITHM
+
+// This header defines __device__ overloads of std::min/max, but only if we're
+// <= C++11.  In C++14, these functions are constexpr, and so are implicitly
+// __host__ __device__.
+//
+// We don't support the initializer_list overloads because
+// initializer_list::begin() and end() are not __host__ __device__ functions.
+//
+// When compiling in C++14 mode, we could force std::min/max to have different
+// implementations for host and device, by declaring the device overloads
+// before the constexpr overloads appear.  We choose not to do this because
+
+//  a) why write our own implementation when we can use one from the standard
+//     library? and
+//  b) libstdc++ is evil and declares min/max inside a header that is included
+//     *before* we include <algorithm>.  So we'd have to unconditionally
+//     declare our __device__ overloads of min/max, but that would pollute
+//     things for people who choose not to include <algorithm>.
+
+#include_next <algorithm>
+
+#if __cplusplus <= 201103L
+
+// We need to define these overloads in exactly the namespace our standard
+// library uses (including the right inline namespace), otherwise they won't be
+// picked up by other functions in the standard library (e.g. functions in
+// <complex>).  Thus the ugliness below.
+#ifdef _LIBCPP_BEGIN_NAMESPACE_STD
+_LIBCPP_BEGIN_NAMESPACE_STD
+#else
+namespace std {
+#ifdef _GLIBCXX_BEGIN_NAMESPACE_VERSION
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+#endif
+#endif
+
+template <class __T, class __Cmp>
+inline __device__ const __T &
+max(const __T &__a, const __T &__b, __Cmp __cmp) {
+  return __cmp(__a, __b) ? __b : __a;
+}
+
+template <class __T>
+inline __device__ const __T &
+max(const __T &__a, const __T &__b) {
+  return __a < __b ? __b : __a;
+}
+
+template <class __T, class __Cmp>
+inline __device__ const __T &
+min(const __T &__a, const __T &__b, __Cmp __cmp) {
+  return __cmp(__b, __a) ? __b : __a;
+}
+
+template <class __T>
+inline __device__ const __T &
+min(const __T &__a, const __T &__b) {
+  return __a < __b ? __b : __a;
+}
+
+#ifdef _LIBCPP_END_NAMESPACE_STD
+_LIBCPP_END_NAMESPACE_STD
+#else
+#ifdef _GLIBCXX_BEGIN_NAMESPACE_VERSION
+_GLIBCXX_END_NAMESPACE_VERSION
+#endif
+} // namespace std
+#endif
+
+#endif // __cplusplus <= 201103L
+#endif // __CLANG_CUDA_WRAPPERS_ALGORITHM