https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93008
Eric Gallager <egallager at gcc dot gnu.org> changed:
What |Removed |Added
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CC| |egallager at gcc dot gnu.org
--- Comment #2 from Eric Gallager <egallager at gcc dot gnu.org> ---
(In reply to Jonathan Wakely from comment #0)
> Currently GCC considers the 'inline' keyword as a hint for inlining, not
> just a request for comdat semantics.
>
> This is a problem in C++20 where arbitrarily complex functions are marked
> 'constexpr' so that they can be used at compile time, and a constexpr
> function is implicitly an inline function. But we do not want the function
> to get additional weighting for runtime optimizations just because it is
> eligible for use in compile-time constant expressions.
>
> It would be useful to have a new attribute that tells the inliner to ignore
> whether the function is 'inline' and only consider its size, use in hot/cold
> regions etc.
>
> Alternatively, do not interpret 'constexpr' on its own as an inlining hint,
> and only treat it as a hint when a constexpr function is explicitly declared
> with the 'inline' specifier (or is defined in the class body).
>
I would prefer this second approach.
>
> constexpr void f() { } // not an inline hint
> constexpr inline void g() { } // inline hint
> inline constexpr void h() { } // inline hint
>
> struct X {
> constexpr void i() { } // inline hint
> };
