This recent GitHub reads like Julia doesn’t do common subexpression elimination at all, is this a correct assumption? Here’s the relevant bits from the issue: using BenchmarkTools f(x) = exp(x)/(1+exp(x)) function g(x) e = exp(x) e/(1 + e) end h!(f::F, v) where {F} = map!(f, v, v) @btime h!…

Yes, as you have very clearly demonstrated, and as is somewhat clearly stated in the issue you linked, julia does not typically do common subexpression elimination. There are some cases where it can do subespression elimination, but it’s probably best to just assume it never happens.

Does Julia do common subexpression elimination?

General Usage Performance

mbauman Split this topic August 17, 2023, 7:44pm 7

2 posts were split to a new topic: Towards implementing CSE in the Julia compiler

Topic		Replies	Views
A simple tool for common subexpression elimination Community package , announcement	2	1264	January 25, 2017
No constant expression elimination for e.g. '2^24-1' Performance question	7	903	November 12, 2019
When does julia infer optimal code, when not? Performance question	4	695	November 16, 2018
Trivial code change causes vectorization failure Performance	3	691	February 1, 2019
Rules for constant elimination General Usage	1	691	October 11, 2017

Does Julia do common subexpression elimination?

Related topics