I am puzzled by this julia> test(flag) = flag ? 1.0 : 1 test (generic function with 2 methods) julia> @code_warntype test(true) Variables #self#::Core.Compiler.Const(test, false) flag::Bool Body::Union{Float64, Int64} 1 ─ goto #4 if not flag 2 ─ return 1.0 3 ─ Core.Compiler.Const(…

[image] pablosanjose: Oh! Why is this? Isn’t true a compile-time constant here? (Still slightly puzzled…) @code_warntype test(true) gets macro expanded to code_warntype(test, Tuple{Bool}) where clearly, all information that the bool was a constant true has been lost.

Wrap in a function: julia> test(flag) = flag ? 1.0 : 1 test (generic function with 1 method) julia> f() = test(true) f (generic function with 1 method) julia> @code_warntype f() Variables #self#::Core.Compiler.Const(f, false) Body::Float64 1 ─ %1 = Main.test(true)::Core.Compiler.Const(1.0, fal…

Oh! Why is this? Isn’t true a compile-time constant here? (Still slightly puzzled…)

See eg [image] Inlining behavior: constant prop. fails, I need help in understanding "why" Performance This is how I usually benchmark constant propagation: julia> function f(x) D = 1 reconstruct(x, D) end f (generic function with 1 method) …

Aaaaah! Got it now… Many thanks to both!

If I may, just a quick followup: why doesn’t this work with kwargs? julia> test(; flag = true) = flag ? 1.0 : 1 test (generic function with 1 method) julia> f() = test(flag = true) f (generic function with 1 method) julia> @code_warntype f() Variables #self#::Core.Compiler.Const(f, false) Body…

Question about constant propagation and inference

General Usage

Tamas_Papp June 3, 2019, 1:10pm 4

See eg

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Question about constant propagation and inference

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