On Tue, Jul 22, 2014 at 09:40:15PM -0600, Jeff Law wrote: > On 07/15/14 23:31, Andi Kleen wrote: > >From: Andi Kleen <a...@linux.intel.com> > > > >No substantial changes, although the hash values will be slightly > >different. > > > >gcc/: > > > >2014-07-10 Andi Kleen <a...@linux.intel.com> > > > > * lto-streamer-out.c (hash_tree): Convert to inchash. > > (add_flag): New macro. > So my question here, does this make any existing LTO objects no longer > usable? If so, what, if any policy do we have when we make that kind of > change?
It breaks the format because a few type hashes change But breaks happen all the time during development. Currently just adding a new command option breaks the format. Or pretty much any change to gimple. Generally in my experience LTO object files don't stay usable more than a few days in phase 1. Currently the format is even broken for patch level releases, usually due to some option change. The policy is just that for a given release that is unchanged the object format stays compatible. I submitted some patches to improve this slightly for the options, but they were not accepted because of all the other issues. https://gcc.gnu.org/ml/gcc-patches/2010-10/msg00099.html Given that reality I assume the patch is ok for you? -Andi a...@linux.intel.com -- Speaking for myself only
