> -----Original Message----- > From: David Rowley <dgrowle...@gmail.com> > Sent: Wednesday, March 20, 2024 5:28 PM > To: Amonson, Paul D <paul.d.amon...@intel.com> > Cc: Nathan Bossart <nathandboss...@gmail.com>; Andres Freund > > I'm not sure about this "extern negates inline" comment. It seems to me the > compiler is perfectly free to inline a static function into an external > function > and it's free to inline the static function elsewhere within the same .c file. > > The final sentence of the following comment that the 0001 patch removes > explains this: > > /* > * When the POPCNT instruction is not available, there's no point in using > * function pointers to vary the implementation between the fast and slow > * method. We instead just make these actual external functions when > * TRY_POPCNT_FAST is not defined. The compiler should be able to inline > * the slow versions here. > */ > > Also, have a look at [1]. You'll see f_slow() wasn't even compiled and the > code > was just inlined into f(). I just added the > __attribute__((noinline)) so that usage() wouldn't just perform constant > folding and just return 6. > > I think, unless you have evidence that some common compiler isn't inlining the > static into the extern then we shouldn't add the macros. > It adds quite a bit of churn to the patch and will break out of core code as > you > no longer have functions named pg_popcount32(), > pg_popcount64() and pg_popcount().
This may be a simple misunderstanding extern != static. If I use the "extern" keyword then a symbol *will* be generated and inline will be ignored. This is NOT true of "static inline", where the compiler will try to inline the method. :) In this patch set: * I removed the macro implementation. * Made everything that could possibly be inlined marked with the "static inline" keyword. * Conditionally made the *_slow() functions "static inline" when TRY_POPCONT_FAST is not set. * Found and fixed some whitespace errors in the AVX code implementation. Thanks, Paul
v12-0001-Refactor-Split-pg_popcount-functions-into-multiple-f.patch
Description: v12-0001-Refactor-Split-pg_popcount-functions-into-multiple-f.patch
v12-0002-Feature-Added-AVX-512-acceleration-to-the-pg_popcoun.patch
Description: v12-0002-Feature-Added-AVX-512-acceleration-to-the-pg_popcoun.patch
