add hip.h

tests/cpp/tree/gpu_hist/test_driver.cu

@@ -1,6 +1,10 @@
 #include <gtest/gtest.h>
 #include "../../../../src/tree/driver.h"
+#if defined(XGBOOST_USE_CUDA)
 #include "../../../../src/tree/gpu_hist/expand_entry.cuh"
+#elif defined(XGBOOST_USE_HIP)
+#include "../../../../src/tree/gpu_hist/expand_entry.hip.h"
+#endif
 
 namespace xgboost {
 namespace tree {

tests/cpp/tree/gpu_hist/test_evaluate_splits.cu

@@ -3,7 +3,11 @@
  */
 #include <gtest/gtest.h>
 
+#if defined(XGBOOST_USE_CUDA)
 #include "../../../../src/tree/gpu_hist/evaluate_splits.cuh"
+#elif defined(XGBOOST_USE_HIP)
+#include "../../../../src/tree/gpu_hist/evaluate_splits.hip.h"
+#endif
 #include "../../helpers.h"
 #include "../../histogram_helpers.h"
 #include "../test_evaluate_splits.h"  // TestPartitionBasedSplit

tests/cpp/tree/gpu_hist/test_histogram.cu

@@ -6,8 +6,13 @@
 #include <vector>
 
 #include "../../../../src/common/categorical.h"
+#if defined(XGBOOST_USE_CUDA)
 #include "../../../../src/tree/gpu_hist/histogram.cuh"
 #include "../../../../src/tree/gpu_hist/row_partitioner.cuh"
+#elif defined(XGBOOST_USE_HIP)
+#include "../../../../src/tree/gpu_hist/histogram.hip.h"
+#include "../../../../src/tree/gpu_hist/row_partitioner.hip.h"
+#endif
 #include "../../../../src/tree/param.h"  // TrainParam
 #include "../../categorical_helpers.h"
 #include "../../helpers.h"

tests/cpp/tree/gpu_hist/test_row_partitioner.cu

@@ -9,7 +9,11 @@
 #include <algorithm>
 #include <vector>
 
+#if defined(XGBOOST_USE_CUDA)
 #include "../../../../src/tree/gpu_hist/row_partitioner.cuh"
+#elif defined(XGBOOST_USE_HIP)
+#include "../../../../src/tree/gpu_hist/row_partitioner.hip.h"
+#endif
 #include "../../helpers.h"
 #include "xgboost/base.h"
 #include "xgboost/context.h"