Pass device pointers to kernels as global LLVMPtrs

docs/src/api/kernels.md

@@ -37,7 +37,7 @@ used by `@oneapi`. Returns a callable kernel object.
 
 Convert arguments for kernel execution. This function is called for every argument passed to
 a kernel, allowing customization of argument conversion. By default, it converts `oneArray`
-to `oneDeviceArray`.
+to `oneDeviceArray`, and `ZePtr{T}` to `LLVMPtr{T,AS.CrossWorkgroup}`.
 
 
 ## Basic Kernel Example

src/compiler/execution.jl

@@ -158,8 +158,9 @@ struct KernelAdaptor
 end
 KernelAdaptor() = KernelAdaptor(nothing)
 
-# convert oneAPI host pointers to device pointers
-Adapt.adapt_storage(to::KernelAdaptor, p::ZePtr{T}) where {T} = reinterpret(Ptr{T}, p)
+# device pointers are passed as global pointers; a plain `Ptr` is a private pointer in SPIR-V
+Adapt.adapt_storage(to::KernelAdaptor, p::ZePtr{T}) where {T} =
+  reinterpret(LLVMPtr{T,AS.CrossWorkgroup}, p)
 
 # convert oneAPI host arrays to device arrays
 function Adapt.adapt_storage(to::KernelAdaptor, xs::oneArray{T,N}) where {T,N}

test/execution.jl

@@ -713,13 +713,28 @@ end
 
     if VERSION < v"1.12"
         a = oneArray(Float32[0])
-        @oneapi kernel(pointer(a))
+        @oneapi kernel(reinterpret(Ptr{Float32}, pointer(a)))
         @test Array(a) == [42]
     else
         @test_broken false
     end
 end
 
+@testset "device pointer arguments" begin
+    # pointers to device memory are passed to kernels as global pointers; a plain `Ptr`
+    # would be a private pointer in SPIR-V, losing the store (#458)
+    function kernel(ptr, val)
+        unsafe_store!(ptr, val)
+        return
+    end
+
+    for B in (oneL0.DeviceBuffer, oneL0.SharedBuffer, oneL0.HostBuffer)
+        a = oneVector{Int,B}([1])
+        @oneapi kernel(pointer(a), 42)
+        @test Array(a) == [42]
+    end
+end
+
 ############################################################################################
 
 # A chain of N live accumulators forces the register allocator to spill once N exceeds