...But, who would disable that (or any other "standard" 8051 optimization) in a real application?

I do. Because once you have multiple register sets in use it becomes very difficult to manage assignment of register sets to functions. And if you want to have a common function, callable from different register set functions, then it's impossible with absolute register addressing turned on...

I think you may have a different opinion of how register banks were intended to be used than I do.

I also think you took my post as a personal attack, which it was not.

I was simply pointing out that there is a great deal of data missing from this thread where comparing compiler output is concerned.

On more of a technical note...if you are going to call a function from multiple register banks, make sure that all arguments fit into registers.

...The optimizer in each of the compilers will do a better job on a larger application.

Absolutely not in Keil's case. It can't even get the simple things right...

I think that there are lot of people who would disagree with your absolute assessment of the Keil tools.

Jon