Iphone wont start

I was changing the settings around on my phone and I messed with the time and date and when I started my phone again it wouldn't work. I let it die but it loaded so slow it kept dying and I couldn't get to the setting. People were saying if you make it a certain date then it bricks your phone but taking the battery out makes it work again. Will the warranty that comes with the phone cover it if that doesn't work?