Messages in this thread | | | Date | Mon, 19 Jun 2017 13:25:22 -0700 (PDT) | From | David Rientjes <> | Subject | Re: [PATCH] compiler, clang: Add always_inline attribute to inline |
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On Mon, 19 Jun 2017, Prasad Sodagudi wrote:
> Commit abb2ea7dfd82 ("compiler, clang: suppress warning for unused > static inline functions") re-defining the 'inline' macro but > __attribute__((always_inline)) is missing. Some compilers may > not honor inline hint if always_iniline attribute not there. > So add always_inline attribute to inline as done by > compiler-gcc.h file. >
IIUC, __attribute__((always_inline)) was only needed for gcc versions < 4 and that the inlining decision making is improved in >= 4. To make a change like this, I would think that we would need to show that clang is making suboptimal decisions. I don't think there's a downside to making CONFIG_OPTIMIZE_INLINING specific only to gcc.
If it is shown that __attribute__((always_inline)) is needed for clang as well, this should be done as part of compiler-gcc.h to avoid duplicated code.
> Signed-off-by: Prasad Sodagudi <psodagud@codeaurora.org> > --- > include/linux/compiler-clang.h | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/include/linux/compiler-clang.h b/include/linux/compiler-clang.h > index d614c5e..deb65b3 100644 > --- a/include/linux/compiler-clang.h > +++ b/include/linux/compiler-clang.h > @@ -22,4 +22,9 @@ > * directives. Suppress the warning in clang as well. > */ > #undef inline > +#if !defined(CONFIG_ARCH_SUPPORTS_OPTIMIZED_INLINING) || \ > + !defined(CONFIG_OPTIMIZE_INLINING) > +#define inline inline __attribute__((always_inline)) __attribute__((unused)) notrace > +#else > #define inline inline __attribute__((unused)) notrace > +#endif
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