Serhiy Storchaka added the comment:
> It looks to me that the patch contain unneeded changes. Some changes don't affect performance, others don't look well justified. Are there benchmarks that confirm the benefit of these changes?

Hum, since I expect disagreements on the changes, I propose to split
the patch into two parts: minimum change to optimize, and a second
change (later, once the first one is merged) to cleanup further the
code.

"Some changes don't affect performance"

Well, a cleanup is supposed to not affect performances at all :-)