On Tue, May 07, 2013 at 11:43:33PM +0200, Jan Hubicka wrote: > > Hi, > > > > the problem in PR 57084 is that late PRE devirtualization creates a > > direct call to a decl fro which we only have an inlined call graph > > mode in the given partition. I tried to find a most universal place > > where to fix it because this problem is not special to type-based > > devirtualization and in theory can be caused by any call to a decl > > that is grabbed from a constructor. I think the best place is the > > following one-liner, because all such decls should go through > > canonicalize_constructor_val. > > > > Bootstrapped and tested on x86_64-linux, fixes the testcase (at -m32) > > and I have happened to also LTO build Mozilla Firefox with it. OK for > > trunk? > > Is this change needed for 4.8, too? It would be OK there.
Although the testcase shows the problem relies on code that is new in 4.9, I think that yes, even the current devirtualization by looking into constructors can hit the bug. So I am going to commit it to 4.8 after testing on that branch. > > For 4.9 I would preffer replacing cgraph_get_create by > cgraph_get_create_real_symbol_node. I believe that all users of > cgraph_get_create are not interested in inline nodes. I just did not want to > make such intrusive change for 4.8... I've looked at all calls to cgraph_get_create_node and pretty much all of them either really want cgraph_get_create_real_symbol_node or at least will not be harmed by doing that. The only two calls I was not so sure about were the one in lto-cgraph.c and in particular the one in lto-streamer-in.c. I'm afraid they might create an extra cgraph node in LTRANS when we would actually want the inlined one. What do you think? I'll give it a go anyway. Thanks, Martin
