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[return to "Std: Clamp generates less efficient assembly than std:min(max,std:max(min,v))"]
1. celega+im[view] [source] 2024-01-16 13:50:05
>>x1f604+(OP)
On gcc 13, the difference in assembly between the min(max()) version and std::clamp is eliminated when I add the -ffast-math flag. I suspect that the two implementations handle one of the arguments being NaN a bit differently.

https://gcc.godbolt.org/z/fGaP6roe9

I see the same behavior on clang 17 as well

https://gcc.godbolt.org/z/6jvnoxWhb

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2. gumby+1n[view] [source] 2024-01-16 13:54:31
>>celega+im
You (celegans25) probably know this but here is a PSA that -ffast-math is really -finaccurate-math. The knowledgeable developer will know when to use it (almost never) while the naive user will have bugs.
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3. alexey+Ov[view] [source] 2024-01-16 14:48:17
>>gumby+1n
If your code ventures into the domain where fast-math matters and you're not a mathematician trying to solve a lyapunov-unstable problem with very tricky numeric methods, then most likely your code is already broken.
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