static inline

[round umbra]

using inline together with static is redundant, you should only use inline without static. Inline also gives a hint to the compiler to inline it so the probability is a bit higher but it says here: https://en.cppreference.com/c/language/inline

The compilers can (and usually do) ignore presence or absence of the inline specifier for the purpose of optimization.

so this usage of inline does not seem to be true when it usually gets ignored for that purpose. So why do David Blackman and Sebastiano Vigna use static inline here: https://prng.di.unimi.it/xoshiro256starstar.c
Vigna is a professor and Blackman a researcher, they published this implementation as the result of their research so i expect everything there to be there for a reason, so what is the reason they use static inline there instead of just static?

[vapid inlet]

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[dusky spindle]

either they analyzed compiler output, either it's cultural belief

[sacred steppe]

We are all victims of our habits sometimes, and i suspect this is a similar case.

Sometime ago when compilers weren't as good, i might of made a difference - today - not so much

As a sidenote - using inline on its own on functions with external linkage means something else entirely (I'm referring to the first line you wrote there. Not sure if you meant something else - just thought to make things clear)

[round umbra]

ok, thank you for your answers

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[proven socket]

checkout https://discord.com/channels/331718482485837825/1486180304640282624

[round umbra]

i know how to use normal inline (not as a hint but its real purpose), i just wondered why people use static inline while it is redundant. But i also do not see why inline is called useless. it is useless with LTO, but if you do not use LTO then it has a use.

[proven socket]

They probably used it as an inline hint

[round umbra]

cppreference says compiler usually ignore the hint, so it is no hint

[proven socket]

I mean, it is still a hint even if it's ignored

[round umbra]

no it would be a hint if it actually increases the probabillity of being inlined

if it just gets ignored with no effect then it is no hint

cppreference says compiler do not care about if inline is there or not for the optimisation purpose they fully decide on their own, without even acknolegding the "hint"

so you would be left with inlines actual purpose which is obsolete when you use static

[proven socket]

#cpp-help-text message

[round umbra]

what is that? msvc implementation of inline for C?

[proven socket]

https://llvm.org/doxygen/InlineCost_8cpp_source.html

[round umbra]

llvm is what i use. ok, then it seems the compiler does not completely ignore it. thank you

[proven socket]

no problem

[dusky spindle]

because people (like me) consider that optimisation is the job of a correct compiler. all things being equal, if the compiler was perfect, LTO would be the default, and inline would have no reason to be.

the arguments that allows you to say register is obsolete, are the same as the arguments against the use of inline : a good compiler should be able to figure out by itself

[round umbra]

i also always use LTO

[dusky spindle]

me too ^^ but I mean, some people consider inline as a good thing

I still don't get their point

[round umbra]

but i was told some libraries do some cracked optimisation relying on a TU being independend and not seen by others. but since i am not able to do such things, i write my code assuming it gets compiled with LTO

but i wanted to learn about inline and all its uses

[dusky spindle]

yes I was going to say: maybe some compiled libraries cannot be inspected enough for the compiler to actually figure out