Comment by teo_zero
7 hours ago
Expecting a piece of code to be compiled to a precise sequence of machine instructions is exactly what you should not do with high-level languages like C++. Their task is exactly to abstract the machine away. They give you the guarantee that the final observable result will be what you asked for, not that the means to obtain that result will be what you have in mind.
If you write a loop to zero out some memory, it can be compiled to a loop, or to a call to an optimized predefined function, or even to a sequence of single zeroing instructions, if the size is small enough.
Even a single statement as a=0 may be compiled to a "load immediate" instruction, or an "XOR with itself", or a "sub with itself", or a move from another register known to be 0.
I'm not sure what this has to do with my comment. I am aware of all of this. It would be nice if an infinite loop was defined to be 'do nothing, indefinitely'. On architectures with an instruction that works that works precisely that way, it could be turned into that, perhaps, but that's an implementation detail and should follow the as-if principle (I'm also not sure any compiler would bother).