[AshamedCaptain]

The article has too many x86 assumptions. The casts are most definitely _not_ free, because there are multiple operations like sign-extending, zero-extending, etc. which depend on the ABI. The fact that these are all almost free in x86 is irrelevant since some architectures will have to go out of their way to implement the operation (albeit the ABI is usually designed to make these operations simple). Similarly, I could also imagine another architecture having a shorter instruction to set a register to 0/1, or even one where _Bool is defined with the machine word size and thus doesn't need any cast whatsoever (not even sign extension).

On such architecture "casting to bool" would be free, but other, narrowing type conversions would not.

[danobi]

Above two comments are very helpful, thanks. I've corrected the -m32 issue.

And thanks for pointing out the x86/ABI assumptions. Had not considered that. It's certainly interesting to think about.