1 files changed, 63 insertions, 0 deletions
diff --git a/tests/optimization/buffer-load-defer-user-pointer.slang b/tests/optimization/buffer-load-defer-user-pointer.slang
new file mode 100644
index 000000000..58e6386f9
--- /dev/null
+++ b/tests/optimization/buffer-load-defer-user-pointer.slang
@@ -0,0 +1,63 @@
+//TEST:SIMPLE(filecheck=SPV): -target spirv -O0
+//TEST:SIMPLE(filecheck=CUDA): -target cuda -entry compute_main -stage compute
+//TEST:SIMPLE(filecheck=PTX): -target ptx -entry compute_main -stage compute
+
+// Check that we can specialize buffer loads through user pointers, and
+// do not load big struct elements into registers unnecessarily.
+
+struct Bottom
+{
+    float bigArray[1024];
+    float bottomGetValue(int index) { return bigArray[index]; }
+}
+
+struct Middle
+{
+    Bottom bottom;
+    float middleGetValue(int index) { return bottom.bottomGetValue(index); }
+}
+
+struct Top
+{
+    StructuredBuffer<Middle*>.Handle middle;
+
+    // Calling `middleGetValue` on `middle[0]` should not causing the entire `Middle`
+    // struct to be loaded into registers. Instead, we should be able to specialize
+    // `middleGetValue` to take a `Middle*` and recursively specialize `bottomGetValue`
+    // to only load the `Bottom.bigArray[index]` element.
+    float topGetValue(int index) { return middle[0].middleGetValue(index); }
+}
+
+struct Root
+{
+    Top top;
+}
+
+ConstantBuffer<Root> cb;
+
+RWStructuredBuffer<float> outputBuffer;
+
+// Check that the generated CUDA code never loads a `Middle` or `Bottom` struct into a local var.
+// CUDA-NOT: Middle{{[_A-Za-z0-9]*}} {{[a-zA-Z0-9_]+}} =
+// CUDA-NOT: Bottom{{[_A-Za-z0-9]*}} {{[a-zA-Z0-9_]+}} =
+// CUDA-NOT: Top{{[_A-Za-z0-9]*}} {{[a-zA-Z0-9_]+}} =
+
+// Check that the generated CUDA code can be compiled by nvrtc correctly into PTX.
+// PTX: compute_main
+
+// Check that the generated (unoptimized) SPIR-V contains a specialized Bottom_bottomGetValue function
+// that takes in a Bottom* and use access chain to load the required array element directly, without 
+// needing to load the entire Bottom struct.
+// SPV: %Bottom_bottomGetValue = OpFunction %float None
+// SPV: OpFunctionParameter %_ptr_PhysicalStorageBuffer_Middle_natural
+// SPV: %[[INDEX:[A-Za-z0-9_]+]] = OpFunctionParameter %int
+// SPV: %[[PTR:[A-Za-z0-9_]+]] = OpAccessChain %_ptr_PhysicalStorageBuffer_float %{{.*}} %[[INDEX]]
+// SPV: %[[VALUE:[A-Za-z0-9_]+]] = OpLoad %float %[[PTR]]
+// SPV: OpReturnValue %[[VALUE]]
+
+[shader("compute")]
+[numthreads(1, 1, 1)]
+void compute_main(uint3 tid: SV_DispatchThreadID)
+{
+    outputBuffer[0] = cb.top.topGetValue(0);
+}