According to the excellent Wikipedia article on LDS temple architecture, the Las Vegas temple is one of about a dozen temples that exhibit the “sloped roof style” that was used for temples in the mid- to late-1980s.
The sloped roof style is also known as skillion roof. I’m having a hard time finding other religious architectural examples, so this may be one of the more authentically creative and novel temple deigns. The use of a single slanted roof is more common in residences. 
A feature of the Las Vegas temple that was novel to me is the walls of windows on the south end. Behind those windows on the upper floor is the celestial room, and since those are southeast and southwest facing windows, in Las Vegas, sunlight floods in through the frosted glass.