John Marino rearranged how GCC5 handles CPUTYPE settings. If you are specifically setting the target CPU when compiling, his commit will give you an exact list of what to target.
Note that I am not saying another architecture – this is all x86_64. I also don’t recommend doing this unless you have a specific use for it – compiler overoptimizations often create more problems than they fix.
Worth noting is that gcc also supports “-march=native” which means that gcc will figure out which CPUTYPE to use, instead of the user.
you can set CPUTYPE=native to enable that. Plus if the value of CPUTYPE is invalid, it sets it to native.