https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68870
--- Comment #7 from rguenther at suse dot de <rguenther at suse dot de> --- On December 15, 2015 3:15:13 AM GMT+01:00, law at redhat dot com <gcc-bugzi...@gcc.gnu.org> wrote: >https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68870 > >--- Comment #6 from Jeffrey A. Law <law at redhat dot com> --- >I'd say that changing genmatch (or any code) to know about the freelist >is a >horrid hack and just papering over the problem. > >I haven't put this case under a debugger, but presumably we've got a >reference >to a released SSA_NAME in the IL, right? We have invalid SSA, a use not dominated by its def. It happens to be in a trivially dead region but CFG cleanup deleting the def first which is in another trivially dead region and then folding the conditional is causing this. Note the conditional happens to be folded before it is deleted as part of the other trivial dead region. So it's the old CFG cleanup ordering issue I tried to fix with the last rev. But forgot that folding code... Presumably in some code that >isn't >trivially proved unreachable? It actually is.
