[Python-Dev] DUP_TOPX (original) (raw)

Guido van Rossum guido@python.org
Fri, 10 Jan 2003 09:56:04 -0500

During a code review, Neal Norwitz noticed that ceval.c defines DUPTOPX 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/)