[Python-Dev] DUP_TOPX

[Guido van Rossum]

> During a code review, Neal Norwitz noticed that ceval.c
> defines DUP_TOPX for x in (1,2,3,4,5) but that compile.c
> never generates that op code with a parameter greater than
> three.
> 
> The question of the day is whether anyone knows of a 
> reason that we can't or shouldn't remove the code for 
> the 4 and 5 cases.  Is there anything else (past or present)
> that can generate this opcode?

Not that I know of.  Now's the time to find out, so let's drop these.

> Taking it out is only a microscopic win, a few saved brain 
> cycles and a smaller byte size for the main eval loop 
> (making it slightly more likely to stay in cache).
> 
> Also, we wanted to know if anyone still had a use for the
> LLTRACE facility built into ceval.c.  It's been there since
> '92 and may possibly not longer be of value.

Haven't used in 5 years I think, so if you want to lose it, be my
guest.

--Guido van Rossum (home page: http://www.python.org/~guido/)