Jussi Pakkanen has been toying around with Clang static analysis and Clang compiling for Qt Creator. Long story short, he's very happy with his compile-time results. He's been playing around with building Qt Creator from scratch using the Meson automatic unity build generator and the Clang compiler, which has led him to having compile times under three minutes.
From a MacBook Pro with a solid-state drive and 16GB of memory (the CPU model wasn't mentioned in his post), a regular, unoptimized build takes almost 27 minutes for building Qt Creator... An optimized build meanwhile takes just over 32 minutes. This is with Qt Creator's default build system. However, with Jussi's changes and using Clang with the Unity build system, a build drops down to two and a half minutes for an unoptimized build or just over six minutes for an optimized build.
Those building Qt Creator and wishing to learn more can see this Qt mailing list post. The numbers jive with our findings too about fast compile times with Clang not only on x86 but also on ARM while the performance of the resulting binaries is mixed. It's common for many game developers and other commercial software studios to do their debug builds with LLVM/Clang for the expedited compile-times and static analysis while most of them are shipping their "release binaries" with GCC.