Does the University of Toronto require a GRE for a MS in computer science?

Short answer, yes. It won’t hurt your case unless the score is too bad but the Computer science department website of University of Toronto states that there is no requirement of GRE test score for the admission process. Submitting IELTS or TOEFL scores will suffice the process of admission for international students. The online application form does provide a field where you can submit your GRE scores, but it is made optional.

However it is recommended to upload a GRE score as it will create an edge over other applicants. Target for a safe score of 320+ in GRE so that you leave no stone unturned to create a good impression.

Tabulation below gives a brief overview on expected test scores of University of Toronto:

When you are applying for such competitive programs, it's always wise to present yourself in the best way possible by keeping your best foot ahead.

Submitting a GRE score along with a good GPA and resume will definitely enhance the chances of your selection.