removing atomics for CPUs under version 1.7

Author: leios

src/atomics.jl

@@ -47,8 +47,8 @@ These operations are performed in one atomic transaction.
 The function returns `old`.
 
 This operation is supported for values of type Int32, Int64, UInt32 and UInt64.
-Additionally, on GPU hardware with compute capability 7.0+, values of type UInt1
-6 are supported.
+Additionally, on GPU hardware with compute capability 7.0+, values of type UInt16 are supported.
+Also: atomic operations for the CPU requires a Julia version of 1.7.0 or above.
 """
 function atomic_cas!(ptr::Ptr{T}, old::T, new::T) where T
     Core.Intrinsics.atomic_pointerreplace(ptr, old, new, :acquire_release, :monotonic)
@@ -62,6 +62,7 @@ It reads the value `old` located at address `ptr` and stores `val` at the same a
 These operations are performed in one atomic transaction. The function returns `old`.
 
 This operation is supported for values of type Int32, Int64, UInt32 and UInt64.
+Also: atomic operations for the CPU requires a Julia version of 1.7.0 or above.
 """
 function atomic_xchg!(ptr::Ptr{T}, b::T) where T
     Core.Intrinsics.atomic_pointerswap(ptr::Ptr{T}, b::T, :monotonic)
@@ -75,6 +76,7 @@ It reads the value `old` located at address `ptr` and uses `val` in the operatio
 These operations are performed in one atomic transaction. The function returns `old`.
 
 This function is somewhat experimental.
+Also: atomic operations for the CPU requires a Julia version of 1.7.0 or above.
 """
 function atomic_op!(ptr::Ptr{T}, op, b::T) where T
     Core.Intrinsics.atomic_pointermodify(ptr::Ptr{T}, op, b::T, :monotonic)
@@ -92,6 +94,7 @@ The function returns `old`.
 
 This operation is supported for values of type Int32, Int64, UInt32, UInt64, and Float32.
 Additionally, on GPU hardware with compute capability 6.0+, values of type Float64 are supported.
+Also: atomic operations for the CPU requires a Julia version of 1.7.0 or above.
 """
 atomic_add!
 
@@ -104,6 +107,7 @@ These operations are performed in one atomic transaction.
 The function returns `old`.
 
 This operation is supported for values of type Int32, Int64, UInt32 and UInt64.
+Also: atomic operations for the CPU requires a Julia version of 1.7.0 or above.
 """
 atomic_sub!
 
@@ -116,6 +120,7 @@ These operations are performed in one atomic transaction.
 The function returns `old`.
 
 This operation is supported for values of type Int32, Int64, UInt32 and UInt64.
+Also: atomic operations for the CPU requires a Julia version of 1.7.0 or above.
 """
 atomic_and!
 
@@ -128,6 +133,7 @@ These operations are performed in one atomic transaction.
 The function returns `old`.
 
 This operation is supported for values of type Int32, Int64, UInt32 and UInt64.
+Also: atomic operations for the CPU requires a Julia version of 1.7.0 or above.
 """
 atomic_or!
 
@@ -140,6 +146,7 @@ These operations are performed in one atomic transaction.
 The function returns `old`.
 
 This operation is supported for values of type Int32, Int64, UInt32 and UInt64.
+Also: atomic operations for the CPU requires a Julia version of 1.7.0 or above.
 """
 atomic_xor!
 
@@ -152,6 +159,7 @@ These operations are performed in one atomic transaction.
 The function returns `old`.
 
 This operation is supported for values of type Int32, Int64, UInt32 and UInt64.
+Also: atomic operations for the CPU requires a Julia version of 1.7.0 or above.
 """
 atomic_min!
 
@@ -164,6 +172,7 @@ These operations are performed in one atomic transaction.
 The function returns `old`.
 
 This operation is supported for values of type Int32, Int64, UInt32 and UInt64.
+Also: atomic operations for the CPU requires a Julia version of 1.7.0 or above.
 """
 atomic_max!
 
@@ -176,6 +185,7 @@ These three operations are performed in one atomic transaction.
 The function returns `old`.
 
 This operation is only supported for values of type Int32.
+Also: atomic operations for the CPU requires a Julia version of 1.7.0 or above.
 """
 atomic_inc!
 
@@ -188,5 +198,6 @@ These three operations are performed in one atomic transaction.
 The function returns `old`.
 
 This operation is only supported for values of type Int32.
+Also: atomic operations for the CPU requires a Julia version of 1.7.0 or above.
 """
 atomic_dec!

src/cpu.jl

@@ -269,3 +269,29 @@ end
 
 # Argument conversion
 KernelAbstractions.argconvert(k::Kernel{CPU}, arg) = arg
+
+###
+# CPU error handling if under 1.7
+###
+
+if Base.VERSION < v"1.7.0"
+    import KernelAbstractions: atomic_add!, atomic_and!, atomic_cas!,
+                               atomic_dec!, atomic_inc!, atomic_max!,
+                               atomic_min!, atomic_op!, atomic_or!,
+                               atomic_sub!, atomic_xchg!, atomic_xor!
+    function atomic_error(args...)
+        error("CPU Atomics are not allowed for julia version under 1.7!"
+    end
+
+    afxs = [atomic_add!, atomic_and!, atomic_cas!, atomic_dec!,
+            atomic_inc!, atomic_max!, atomic_min!, atomic_op!,
+            atomic_or!, atomic_sub!, atomic_xchg!, atomic_xor! ]
+    for afx in afxs
+        @inline function Cassette.overdub(::CPUCtx, ::typeof(afx), args...)
+            atomic_error(args...)
+        end
+    end
+end
+
+end
+

test/testsuite.jl

@@ -70,7 +70,8 @@ function testsuite(backend, backend_str, backend_mod, AT, DAT)
         convert_testsuite(backend, AT)
     end
 
-    if backend_str != "ROCM"
+    if backend_str != "ROCM" &&
+      !(backend_str == "CPU" && Base.VERSION < v"1.7.0")
         @testset "Atomics" begin
             atomics_testsuite(backend, AT)
         end