do any games use four screen mirroring? which mapper supports it?

Sure, Boulder Dash uses it for example.
And I guess any mapper can support it, since it's just 2k extra VRAM, wich make space for 4 nametables instead of 2. However, this game was a MMC 1.

thanks,but does this mean when four screen mirroring is used it overrides vertical and horizontal mirroring,because i see no mapper which allows in-game switching between four screen mirroring and other mirroring types.

Yeah, it would probably always override the mirroring. There aren't any mapper controls related to it that I'm aware of. Though I do recall seeing something like a 'one-screen mirroring' feature for the MMC1 (I think it was MMC1).

As nice as a feature that it is, games that use 4-screen are very uncommon. In fact, the only north american release I know of that uses it is Gauntlet (MMC3).

Rad Racer 2

Yes, it has actually nothing to do with mirroring, since you can get 4 real nametables. And the MMC1 has a one screen mirroring feature, I actually don't know how it works on fourscreen games. I guess its disabled.