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- A large fraction of compiler time is spent on code generation; how many of those lines did the compiler actually generate code for? (i.e. not unused functions or uninstantiated templates)

(And in the case of uninstantiated templates, a C++ compiler doesn't even need to type check them…)

- Did you have optimizations enabled?

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> how many of those lines did the compiler actually generate code for?

Not many. How many lines would a comparable Rust program have to instantiate? (should be the same)

All I was trying to do was make an apples to apples comparison by discrediting the implication that the clang++ and g++ compilers are only faster because people use separate compilation units.

I think it's fair to compare Rust and C++ this way, and if Rust is slower to compile, then it's fair to ask why.

> Did you have optimizations enabled?

Yes, -O3. Also -Wall -Wextra and -fwrapv if you're interested.

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