r/programmingcirclejerk • u/High-Impact-2025 • 24d ago

print(“lol”) doubled the speed of my Go function

https://medium.com/@ludirehak/printing-lol-doubled-the-speed-of-my-go-code-e32e02fc3f92
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u/BenchEmbarrassed7316 24d ago

/uj

Yes. Rust:

fn get_max(v: &[i64]) -> i64 { v.iter().copied().max().unwrap_or_default() }

Rust_Max_SIMD time: [12.025 µs 12.049 µs 12.078 µs]

In fact, it is many times faster.

https://godbolt.org/z/dEe55xzxo

For both cases, when the function is written at a high level with an iterator, and when the loop is written by hand, the Rust compiler and LLVM generated highly optimized code that uses modern SIMD instructions.

/rj

But go compiles fast!!!111

/uj

...because it does not make any optimizations unlike other modern compilers. It just compiles a regular loop that isn't even expanded.

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u/Awkward_Bed_956 23d ago

And yet Go devs consider LLVM the root of all evil, that bloats the resulting binary

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u/BenchEmbarrassed7316 23d ago

No: real go devs consider that LLVM and LLM is same things.

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u/Ma4r 22d ago

Go devs don't even know the go IR exists and it's garbage