Ah - my mistake; I somehow misread your comment. Pity about the RSS regression.
Personally I have plenty of RAM and I'd happily use more in exchange for a faster compile. Its much cheaper to buy more ram than a faster CPU, but I certainly understand the choice.
With compilers I sometimes wonder if it wouldn't be better to just switch to an arena allocator for the whole compilation job. But it wouldn't surprise me if LLVM allocates way more memory than you'd expect.
