> I tried backing up allocation coalescing (by backing up changes 1.8
> -> 1.9 and 1.10 -> 1.11 of asmcomp/senectgen.ml), but that only
> increased the number of memory accesses.

I'm not surprised that allocation coalescing reduces the number of
memory accesses, indeed.

> Do you have another guess
> what else was changed between 2.01 and 2.02 that could have caused
> the increase of the number of memory accesses?

Some library functions (on which your code may depend) have been
reimplemented differently, most notably Printf.sprintf.  That's all I
can see.  

- Xavier Leroy