Size classes on Modal Views

I am trying to set different constraints for iPad and iPhone (4'').

I have set Regular Height and Compact width constraints for iPhone. But these constraints are shown on 7.9'' iPad, 9.7'' iPad.

These constraints are for a modal view.

How do i make my Regular Height and Compact width constraints limit to my iPhones only.

Because the form sheet presentation on iPad is compact width and regular height, It is taking those constraints.

Formsheet ios 8 constraints are same as iphones constraints

The solution is to override traitCollection in the Presented view controller

override var traitCollection: UITraitCollection
{
    if UIDevice.isIPad()
    {
        let traits = UITraitCollection(horizontalSizeClass: UIUserInterfaceSizeClass.Regular)
        let traits2 = UITraitCollection(verticalSizeClass: UIUserInterfaceSizeClass.Regular)
        let traitCollection = UITraitCollection(traitsFromCollections: [traits, traits2])

        return traitCollection
    }
    else
    {
        return super.traitCollection
    }
}