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	1224	January 25, 2017
No constant expression elimination for e.g. '2^24-1' Performance question	7	877	November 12, 2019
Simplify Julia Expr with Symbolics.jl General Usage question , symbolics	2	269	February 25, 2024
Simplifying Symbolics.jl expression General Usage symbolics	2	119	September 3, 2024
Rules for constant elimination General Usage	1	681	October 11, 2017

Does Julia do common subexpression elimination?

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