This is what CIC says about accelerated studies
Accelerated studies
If a student completes their studies in less time than the normal length of the program (that is, they have accelerated their studies), the post-graduation work permit should be assessed on the length of the program of study.
For example, if the student is enrolled in a program of study that is normally 1 year in duration, but the student completes the requirements for the program of study within 8 months, they may be eligible for a post-graduation work permit that is valid for 1 year.