On Thu, Mar 07, 2019 at 09:00:49AM -0800, Linus Torvalds wrote: > On Thu, Mar 7, 2019 at 8:47 AM Josh Poimboeuf <jpoim...@redhat.com> wrote: > > > > This "fixes" it, and also seems to help -Os make much code: > > Yeah, considering that this __trace_if() macro from hell is doing an > 'if()' on the result of that inner thing, it makes sense to *not* use > that "looks simpler and shorter" array sequence, but depend on the > compiler then noticing that the conditionals are the same and joining > the two branches together. > > The compiler has to do much more work to either generate the actual > dynamic array thing, or notice that the _index_ of the array matches > the _conditional_ on the branch, and undo that thing.
Yeah, agreed. Now it doesn't have to do the funky xor thing to convert the conditional to an int. > But that macro really is the macro from hell regardless. > > Do people really use CONFIG_PROFILE_ALL_BRANCHES? IIRC, Steven runs it once a year or so... -- Josh
