Qx compiler option and AMD processors

[ggveldkamp2]

I am deciding which compiler optimization options to use for a release version of our software. I am thinking about using "/O2 /QxK" or "/O2 /QxK /QaxW", this will make the minimum required cpu a Pentium III. Will the generated code also run on AMD processors with SSE (e.g. Athlon XP and better)?

Thanks,

Guido Veldkamp

[Steven_L_Intel1]

Yes, the code will run on AMD processors, but with SSE and not SSE2 instructions. If you're going to use /Qax you may as well use /QaxN (along with ./QxK to get better performance on Intel Pentium 4 and later processors. When using the auto-CPU-dispatch (/Qax) options, non-Intel processors take the generic path (which you can set with /Qx).

[ggveldkamp2]

Thanks Steve. Using the auto-CPU-dispatch options increases the size of the programs significantly. We have many programs that are run very often for a relative short time, so program loading time is also important. Using "/QxK /QaxW" increases the size about 15% compared to "/QxK". I will have to try to see what's best for us. I will also try "/QxK /QaxN".

[Steven_L_Intel1]

If the programs run for short times, it does not make sense to me to spend effort optimizing them. Just use /QxK and let it be.