The vec_step operator

The vec_step operator takes a vector type operand and returns an integer value representing the amount by which a pointer to a vector element should be incremented in order to move by 16 bytes (the size of a vector), or equivalently, the number of elements in the vector. The following table provides a summary of values by data type.

Table 1. Increment value for vec_step by data type
`vec_step` expresssion	Value
`vec_step(vector unsigned char)` `vec_step(vector signed char)` `vec_step(vector bool char)`	16
`vec_step(vector unsigned short)` `vec_step(vector signed short)` `vec_step(vector bool short)`	8
`vec_step(vector unsigned int)` `vec_step(vector signed int)` `vec_step(vector bool int)`	4
`vec_step(vector unsigned long long)` `vec_step(vector signed long long)` `vec_step(vector bool long long)`	2
`vec_step(vector double)`	2