OpenCL requires all types to be naturally aligned. /* * Vector types * * Note: OpenCL requires that all types be naturally aligned. * This means that vector types must be naturally aligned. * For example, a vector of four floats must be aligned to * a 16 byte boundary (calculated as 4 * the natural 4-byte * alignment of the float). The alignment qualifiers here * will only function properly if your compiler supports them * and if you don't actively work to defeat them. For example, * in order for a cl_float4 to be 16 byte aligned in a struct, * the start of the struct must itself be 16-byte aligned.
http://d.puremagic.com/issues/show_bug.cgi?id=2278
