diff --git a/libs/vkd3d/device.c b/libs/vkd3d/device.c
index 65aa4b6a..0a41f5f7 100644
--- a/libs/vkd3d/device.c
+++ b/libs/vkd3d/device.c
@@ -719,7 +719,7 @@ static HRESULT STDMETHODCALLTYPE d3d12_device_CreateRootSignature(ID3D12Device *
     if (node_mask && node_mask != 1)
         FIXME("Ignoring node mask 0x%08x.\n", node_mask);
 
-    if (bytecode_length != ~0u)
+    if (bytecode_length != ~(SIZE_T)0)
     {
         FIXME("Root signature byte code not supported.\n");
         return E_NOTIMPL;
diff --git a/tests/d3d12.c b/tests/d3d12.c
index def9aeaf..3cf390d9 100644
--- a/tests/d3d12.c
+++ b/tests/d3d12.c
@@ -105,7 +105,7 @@ static HRESULT create_root_signature_(unsigned int line, ID3D12Device *device,
 static HRESULT create_root_signature_(unsigned int line, ID3D12Device *device,
         const D3D12_ROOT_SIGNATURE_DESC *desc, ID3D12RootSignature **root_signature)
 {
-    return ID3D12Device_CreateRootSignature(device, 0, desc, ~0u,
+    return ID3D12Device_CreateRootSignature(device, 0, desc, ~(SIZE_T)0,
             &IID_ID3D12RootSignature, (void **)root_signature);
 }
 #endif