Query regarding backend of Clang

Dear LLVM Team
I am looking for a llvm beasede compiler nad dont want to use GCC or any other based compiler. I have installed the clang++ and LLVM by following instruction from page http://clang.llvm.org/get_started.html

I want to use LLVM based compiler for making some changes in ANSI C compiler for a project. My goal is to use LLVM compiler so that compilation process becomes fast.

Could please tell me that do I need to use some other compiler or by following the above mentioned instruction I have installed LLVM based compiler. As Clang++ is just a front end and uses other compiler in backend. So is it a LLVM based compiler or GCC based compiler?
And is ther any way that I can check which compiler Clang++ is using?

Thanks and Regards

Clang is a frontend *for the LLVM compiler*. For more information,
check out the homepage [1], but I think you've already installed what
you're looking for.

[1]: http://clang.llvm.org

Further questions about clang should probably go to cfe-dev [2] (if
you have questions about "hacking on clang") or cfe-users [3] (if you
have questions about "using clang").

[2]: http://lists.cs.uiuc.edu/mailman/listinfo/cfe-dev
[3]: http://lists.cs.uiuc.edu/mailman/listinfo/cfe-users