[SYCL] Fix Host Device sampler coordinate conversion (#3226)

The None and Clamp sampler are incorrectly calculating isOutOfRange predicate when the image dimensions are less than 3. This is because the shorthand float conversion used for the samplers uses 0 for the missing dimensions. But that isn't correct, when linearly sampling, the pixel center is at 0.5. Setting it to 0 then leads to an 'out of bounds' for those undefined dimensions. This fix is to use 0.5 for missing dimension.

Signed-off-by: Chris Perkins <[email protected]>

Author: cperkinsintel

sycl/include/CL/sycl/detail/image_accessor_util.hpp

@@ -52,17 +52,19 @@ UnnormalizeCoordinates(const vec<T, 4> &Coords, const range<3> &Range) {
 }
 
 // Converts the Coordinates from any dimensions into float4.
+// valid but unused coordinates are written as 0.5 so the Int_uvwsubhalf
+// calculation won't pass 0.
 // Non-valid coordinates are written as 0.
 template <typename T>
 detail::enable_if_t<IsValidCoordType<T>::value, cl_float4>
 convertToFloat4(T Coords) {
-  return {static_cast<float>(Coords), 0.f, 0.f, 0.f};
+  return {static_cast<float>(Coords), 0.5f, 0.5f, 0.f};
 }
 
 template <typename T>
 detail::enable_if_t<IsValidCoordType<T>::value, cl_float4>
 convertToFloat4(vec<T, 2> Coords) {
-  return {static_cast<float>(Coords.x()), static_cast<float>(Coords.y()), 0.f,
+  return {static_cast<float>(Coords.x()), static_cast<float>(Coords.y()), 0.5f,
           0.f};
 }