Yes and no. While verifying you should benchmark too. Maybe the inline option is slower! Don't try to outclever or force compiler to do weird things and be know

Yes and no. While verifying you should benchmark too. Maybe the inline option is slower! Don't try to outclever or force compiler to do weird things and be knowledgeable about limitations due to compilation steps and the ABI limitations is the lesson. Most of the time using contexpr and defining inlineable functions in headers will get you the most optimal result. In the most of the remaining part the compiler is again right to not inline things because it probably knows more about the instruction caches etc than you. The remaining tiny part is basically PhD or very expert level experience which makes it your job to know more than the compiler because it is your job to write the compiler or discover its shortcomings.