@alexcrichton Will do.
Here are the results for rust-belt, a Piston game, on macOS (with cargo cleans in between).
Specs: Macbook Pro i7-4980HQ (4 core / 8 thread) CPU @ 2.80GHz with SSD
$ time cargo +nightly build --release
real 1m37.498s
user 5m45.737s
sys 0m15.276s
$ RUSTFLAGS="-C codegen-units=16 -Z thinlto" time cargo +nightly build --release
99.09 real 527.33 user 17.32 sys
If I’m reading that correctly, the compile time slowed down about 1% when ThinLTO was enabled.