>"As fast as C" is not a lie. It literally translates to C.
No, just because it outputs C it doesn't mean it's as fast as hand-written C. Using that logic, every language that outputs machine code is as fast as assembly, which is obviously not true.
No, just because it outputs C it doesn't mean it's as fast as hand-written C. Using that logic, every language that outputs machine code is as fast as assembly, which is obviously not true.
As long as you use the same data structures and algos, you'll get the same perf.
There's stuff like bounds checking, but it can be disabled, and it adds like 5%.