================ @@ -4408,6 +4409,42 @@ Target-Specific Extensions Clang supports some language features conditionally on some targets. +AMDGPU Language Extensions +-------------------------- + +__builtin_amdgcn_fence +^^^^^^^^^^^^^^^^^^^^^^ + +``__builtin_amdgcn_fence`` emits a fence. + +* ``unsigned`` atomic ordering, e.g. ``__ATOMIC_ACQUIRE`` +* ``const char *`` synchronization scope, e.g. ``workgroup`` +* Zero or more ``const char *`` address spaces names. + +The address spaces arguments must be string literals with known values, such as: + +* ``"local"`` +* ``"global"`` +* ``"image"`` + +If one or more address space name are provided, the code generator will attempt +to emit potentially faster instructions that only fence those address spaces. +Emitting such instructions may not always be possible and the compiler is free +to fence more aggressively. + +If no address spaces names are provided, all address spaces are fenced. + +.. code-block:: c++ + + // Fence all address spaces. + __builtin_amdgcn_fence(__ATOMIC_SEQ_CST, "workgroup"); + __builtin_amdgcn_fence(__ATOMIC_ACQUIRE, "agent"); + + // Fence only requested address spaces. + __builtin_amdgcn_fence(__ATOMIC_SEQ_CST, "workgroup", "local") ---------------- Pierre-vh wrote:
I wasusing the OpenCL terminology: https://registry.khronos.org/OpenCL/sdk/3.0/docs/man/html/atomic_work_item_fence.html > flags must be set to CLK_GLOBAL_MEM_FENCE, CLK_LOCAL_MEM_FENCE, > CLK_IMAGE_MEM_FENCE Thinking about it, maybe it's better to use names consistent with our AMDGPUAS definitions, so image would just be "private" but local/global stay. What do you think? https://github.com/llvm/llvm-project/pull/78572 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
