On Fri, Sep 06, 2019 at 06:04:54PM -0700, Nick Desaulniers wrote: > On Fri, Sep 6, 2019 at 5:14 PM Segher Boessenkool > <seg...@kernel.crashing.org> wrote: > > On Fri, Sep 06, 2019 at 04:42:58PM -0700, Nick Desaulniers via gcc-patches > > wrote: > > > Just to prove my point about version checks being brittle, it looks > > > like Rasmus' version check isn't even right. GCC supported `asm > > > inline` back in the 8.3 release, not 9.1 as in this patch: > > > > Yes, I backported it so that it is available in 7.5, 8.3, and 9.1, so > > that more users will have this available sooner. (7.5 has not been > > released yet, but asm inline has been supported in GCC 7 since Jan 2 > > this year). > > Ah, ok that makes sense. > > How would you even write a version check for that?
I wouldn't. Please stop using that straw man. I'm not saying version checks are good, or useful for most things. I am saying they are not. Predefined compiler symbols to do version checking (of a feature) is just a lesser instance of the same problem though. (And it causes its own more or less obvious problems as well). > > > Or was it "broken" until 9.1? Lord knows, as `asm inline` wasn't in > > > any release notes or bug reports I can find: > > > > https://gcc.gnu.org/ml/gcc-patches/2019-02/msg01143.html > > > > It never was accepted, and I dropped the ball. > > Ah, ok, that's fine, so documentation was at least written. Tracking > when and where patches land (or don't) is difficult when patch files > are emailed around. I try to keep track of when and where our kernel > patches land, but I frequently drop the ball there. I keep track of most things just fine... But the release notes are part of our web content, which is in a separate CVS repository (still nicer than SVN :-) ), and since I don't use it very often it falls outside of all my normal procedures. > your preference). I'm already subscribed to more mailing lists than I > have time to read. > > > But I'll try to remember, sure. > > Not that I am involved in all such discussions myself, mind. > > But you _did_ implement `asm inline`. ;) That started as just + /* If this asm is asm inline, count anything as minimum size. */ + if (gimple_asm_inline_p (as_a <gasm *> (stmt))) + count = MIN (1, count); (in estimate_num_insns) but then things ballooned. Like such things do. Segher
