OpenCL C standard is based on the strict aliasing rules of the C99 standard. What is meant by strict aliasing rule? Consider the following example:
cl_int data; cl_int *pToIntData = &data; cl_short *pToShortData = (cl_short *)pToIntData; //Now one can access the sub data as follows cl_short hi = pToShortData[1]; cl_short lo = pToShortData[0];
In the preceding example pToShortData is an alias to pToIntData. According to C99 standard an alias cannot be created for the type other than the original. Though the preceding code will compile just fine and may result in a correct behavior since you are only reading from the aliased pointer, but when you write to an aliased pointer, compiler will result in a "strict aliasing rule broken" warning and will result in an undefined behavior. The GCC compiler will throw a warning at higher optimization levels. Similarly aliasing a vector type pointer to a different data type pointer is illegal, though it may be correct since built-in vector...