Hi Guys,
I want to share my experience. I was international student in Canada. I had my study permit till March 31 2016 and I graduated in Dec 20, 2015. I went my back home on Dec 26, 2015 and I came back to Canada on Feb 26, 2016 and Once I came back I applied for my PGWP.
Additional Info, When I was in my back home I have renewed my passport so my TRV was in old Passport. I traveled with old and new passport when I can back to Canada.
I believe as long as you have valid study permit and valid TRV, you can leave Canada and come back before your TRV and study permit expired.
Have any question, feel free to ask!
Thanks,
Krunal