[SYCL][CUDA][libclc] Added atomics with scopes and memory orders (#4820)

Added libclc implementations for CUDA atomics, including for various scopes and memory orders. They are implemented using LLVM intrinsics and exposed as clang builtins, which are than used to implement functions in libclc.

Author: t4c1

clang/include/clang/Basic/BuiltinsNVPTX.def

@@ -85,5 +85,13 @@ images/image_helpers.ll
 images/image.cl
 group/collectives_helpers.ll
 group/collectives.cl
-SPV_EXT_shader_atomic_float_add/atomicfaddext.cl
-SPV_EXT_shader_atomic_float_add/faddext_helpers.ll
+atomic/atomic_add.cl
+atomic/atomic_and.cl
+atomic/atomic_cmpxchg.cl
+atomic/atomic_dec.cl
+atomic/atomic_inc.cl
+atomic/atomic_max.cl
+atomic/atomic_min.cl
+atomic/atomic_xchg.cl
+atomic/atomic_or.cl
+atomic/atomic_xor.cl

clang/lib/CodeGen/CGBuiltin.cpp

@@ -0,0 +1,25 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#include <atomic_helpers.h>
+#include <spirv/spirv.h>
+#include <spirv/spirv_types.h>
+
+__CLC_NVVM_ATOMIC(int, i, int, i, add, _Z18__spirv_AtomicIAdd)
+__CLC_NVVM_ATOMIC(uint, j, int, i, add, _Z18__spirv_AtomicIAdd)
+__CLC_NVVM_ATOMIC(long, l, long, l, add, _Z18__spirv_AtomicIAdd)
+__CLC_NVVM_ATOMIC(ulong, m, long, l, add, _Z18__spirv_AtomicIAdd)
+
+__CLC_NVVM_ATOMIC(float, f, float, f, add, _Z21__spirv_AtomicFAddEXT)
+#ifdef cl_khr_int64_base_atomics
+__CLC_NVVM_ATOMIC(double, d, double, d, add, _Z21__spirv_AtomicFAddEXT)
+#endif
+
+#undef __CLC_NVVM_ATOMIC_TYPES
+#undef __CLC_NVVM_ATOMIC
+#undef __CLC_NVVM_ATOMIC_IMPL

clang/test/CodeGen/builtins-nvptx.c

@@ -0,0 +1,20 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#include <atomic_helpers.h>
+#include <spirv/spirv.h>
+#include <spirv/spirv_types.h>
+
+__CLC_NVVM_ATOMIC(int, i, int, i, and, _Z17__spirv_AtomicAnd)
+__CLC_NVVM_ATOMIC(long, l, long, l, and, _Z17__spirv_AtomicAnd)
+__CLC_NVVM_ATOMIC(unsigned int, j, int, i, and, _Z17__spirv_AtomicAnd)
+__CLC_NVVM_ATOMIC(unsigned long, m, long, l, and, _Z17__spirv_AtomicAnd)
+
+#undef __CLC_NVVM_ATOMIC_TYPES
+#undef __CLC_NVVM_ATOMIC
+#undef __CLC_NVVM_ATOMIC_IMPL