http://www.cbc.ca/news/business/discount-retail-boom-1.3997734
Article from earlier in the year talks about how Giant Tiger was expanding.
Giant Tiger seems to be associated with "small town Canada" a lot.
Its presence in the GTA as it approaches the city itself seems barely felt by Torontonians. It maintains a little foothold within the city limits -- a couple of locations in Scarborough, and one in Etobicoke. All are within striking distance of a Walmart though.