[clang] [libc] [Clang] Implement resource directory headers for common GPU intrinsics (PR #110179)

[Johannes Doerfert via cfe-commits]

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@@ -0,0 +1,191 @@
+//===-- gpuintrin.h - Generic GPU intrinsic functions ---------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// Provides wrappers around the clang builtins for accessing GPU hardware
+// features. The interface is intended to be portable between architectures, but
+// some targets may provide different implementations. This header can be
+// included for all the common GPU programming languages, namely OpenMP, HIP,
+// CUDA, and OpenCL.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef __GPUINTRIN_H
+#define __GPUINTRIN_H
+
+#if !defined(_DEFAULT_FN_ATTRS)
+#if defined(__HIP__) || defined(__CUDA__)
+#define _DEFAULT_FN_ATTRS __attribute__((device))
+#else
+#define _DEFAULT_FN_ATTRS
+#endif
+#endif
+
+#if defined(__NVPTX__)
+#include <nvptxintrin.h>
+#elif defined(__AMDGPU__)
+#include <amdgpuintrin.h>
+#else
+#error "This header is only meant to be used on GPU architectures."
+#endif
+
+#include <stdint.h>
+
+#if !defined(__cplusplus)
+_Pragma("push_macro(\"bool\")");
+#define bool _Bool
+#endif
+
+_Pragma("omp begin declare target device_type(nohost)");
+_Pragma("omp begin declare variant match(device = {kind(gpu)})");
+
+// Returns the number of blocks in the requested dimension.
+_DEFAULT_FN_ATTRS static __inline__ uint32_t __gpu_num_blocks(int __dim) {
+  switch (__dim) {
+  case 0:
+    return __gpu_num_blocks_x();
+  case 1:
+    return __gpu_num_blocks_y();
+  case 2:
+    return __gpu_num_blocks_z();
+  default:
+    __builtin_unreachable();
+  }
+}
+
+// Returns the number of block id in the requested dimension.
+_DEFAULT_FN_ATTRS static __inline__ uint32_t __gpu_block_id(int __dim) {
+  switch (__dim) {
+  case 0:
+    return __gpu_block_id_x();
+  case 1:
+    return __gpu_block_id_y();
+  case 2:
+    return __gpu_block_id_z();
+  default:
+    __builtin_unreachable();
+  }
+}
+
+// Returns the number of threads in the requested dimension.
+_DEFAULT_FN_ATTRS static __inline__ uint32_t __gpu_num_threads(int __dim) {
+  switch (__dim) {
+  case 0:
+    return __gpu_num_threads_x();
+  case 1:
+    return __gpu_num_threads_y();
+  case 2:
+    return __gpu_num_threads_z();
+  default:
+    __builtin_unreachable();
+  }
+}
+
+// Returns the thread id in the requested dimension.
+_DEFAULT_FN_ATTRS static __inline__ uint32_t __gpu_thread_id(int __dim) {
+  switch (__dim) {
+  case 0:
+    return __gpu_thread_id_x();
+  case 1:
+    return __gpu_thread_id_y();
+  case 2:
+    return __gpu_thread_id_z();
+  default:
+    __builtin_unreachable();
+  }
+}
+
+// Get the first active thread inside the lane.
+_DEFAULT_FN_ATTRS static __inline__ uint64_t
+__gpu_first_lane_id(uint64_t __lane_mask) {
+  return __builtin_ffsll(__lane_mask) - 1;
+}
+
+// Conditional that is only true for a single thread in a lane.
+_DEFAULT_FN_ATTRS static __inline__ bool
+__gpu_is_first_in_lane(uint64_t __lane_mask) {
+  return __gpu_lane_id() == __gpu_first_lane_id(__lane_mask);
+}
+
+// Gets the first floating point value from the active lanes.
+_DEFAULT_FN_ATTRS static __inline__ float
+__gpu_read_first_lane_f32(uint64_t __lane_mask, float __x) {
+  return __builtin_bit_cast(
+      float, __gpu_read_first_lane_u32(__lane_mask,
+                                       __builtin_bit_cast(uint32_t, __x)));
+}
+
+// Gets the first floating point value from the active lanes.
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jdoerfert wrote:

Copy and paste errors, also below.

https://github.com/llvm/llvm-project/pull/110179