Loop vectorization methods and apparatus are disclosed. An example method includes generating a first control mask for a set of iterations of a loop by evaluating a condition of the loop, wherein generating the first control mask includes setting a bit of the control mask to a first value when the condition indicates that an operation of the loop is to be executed, and setting the bit of the first control mask to a second value when the condition indicates that the operation of the loop is to be bypassed. The example method also includes compressing indexes corresponding to the first set of iterations of the loop according to the first control mask.