Performance: the C case


 C's performance comes from low-level programming.

 The cost is hazardous behavior, safeness being the programmer's job, which doesn't scale.

 Performance doesn't need to imply unsafeness
using higher-level libraries gives the same performance without loosing safeness
separating low-level programming from high-level programming is a solution (see C# and pliant)

 optimizing C programs is hard and/or dangerous
explicit parallelism hidden
complex memory aliasing (eg: untagged unions)
no way to differentiate requirements from unthought choices (eg: aligned vs non-aligned structs)
program analysis very hard