Without using any extra dependencies the most concise version of your code is this:
NSDictionary *views = @{ @"view" : view };
[parentView addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"|[view]|" options:0 metrics:nil views:views]];
[parentView addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"V:|[view]|" options:0 metrics:nil views:views]];
(You don't need to have the array variables, zero padding assumed and H: is the default axis value).
You could use my auto layout convenience category which would allow the following:
[view pinToSuperviewEdges:JRTViewPinAllEdges inset:0];