Re: [PATCH] compiler: enable CONFIG_OPTIMIZE_INLINING forcibly

[Miguel Ojeda]

On Mon, Sep 30, 2019 at 11:50 PM Nick Desaulniers
<ndesaulniers@xxxxxxxxxx> wrote:
>
> So __attribute__((always_inline)) doesn't guarantee that code will be
> inlined.  [...] inline and __attribute__((always_inline))
> are a heuristic laden mess and should not be relied upon.

Small note: in GCC, __attribute__((always_inline)) is documented as
actually guaranteeing to either inline or error otherwise (although
see the remark for indirect calls):

    "Failure to inline such a function is diagnosed as an error. Note
that if such a function is called indirectly the compiler may or may
not inline it depending on optimization level and a failure to inline
an indirect call may or may not be diagnosed."

As for LLVM/Clang, no idea, since it does not say anything about it in
the docs -- but from what you say, it is a weaker guarantee.

Cheers,
Miguel