On Mon, Jul 17, 2023 at 12:21 AM Tamar Christina via Gcc-patches <gcc-patches@gcc.gnu.org> wrote: > > > -----Original Message----- > > From: Richard Biener <richard.guent...@gmail.com> > > Sent: Monday, July 17, 2023 7:19 AM > > To: Roger Sayle <ro...@nextmovesoftware.com> > > Cc: gcc-patches@gcc.gnu.org; Tamar Christina <tamar.christ...@arm.com> > > Subject: Re: [PATCH] Fix bootstrap failure (with g++ 4.8.5) in > > tree-if-conv.cc. > > > > On Fri, Jul 14, 2023 at 8:56 PM Roger Sayle <ro...@nextmovesoftware.com> > > wrote: > > > > > > > > > > > > This patch fixes the bootstrap failure I'm seeing using gcc 4.8.5 as > > > > > > the host compiler. Ok for mainline? [I might be missing something] > > > > OK. Btw, while I didn't spot this during review I would appreciate > > if the code could use vec.[q]sort, this should work with a lambda as well I > > think. > > That was my first use, but that hits > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99469
That is not hitting PR 99469 but rather it means your comparison is not correct for an (unstable) sort. That is qsort comparator should have this relationship `f(a,b) == !f(b, a)` and `f(a,a)` should also return false. If you are running into this for qsort here, you will most likely run into issues with std::sort later on too. Thanks, Andrew > > Regards, > Tamar
