On Mon, Apr 9, 2012 at 12:18 PM, Jan Hubicka <hubi...@ucw.cz> wrote: > Hi, > this patch fixes several different ICEs related to handling aliases in WHOPR > partitioning. It took me over week debug this, but when variable alias > is added to a boundary and its destination is not added, we get queue of > unforutnate events where the destinatoin gets analyzed and added at ltrans > time > resulting in interesting miscompilation seen at Mozilla with some vtables. > The problem is that constructor won't get streamed when the declaration is > not in varpool at partitioning time and thus once the variable is re-added > it has zero constructor. > Of course the problem manifests itself in various weird ways depending > on ordering of linker command maing it very difficult to reduce anything. > > While working on this I also noticed that PR 52634 is about related problem > where aliases are incorectly partitioned into multiple partitions. > The patch also fixes the varpool ICEs mentioned in the other two PRs. > I failed to produce testcase version of PR52722 testcase, since it does not > link now either, but it won't ICE. > > I will commit the patch and wait for some time, but I would like to backport > it to 4.7, since it solves quite nasty misoptimization problem. > At mainline after this patch i would like to follow with series of cleanups > and API changes I have in queue for symtab work. > > Honza > > PR lto/52722 > PR lto/51765 > PR lto/52634 > * lto-cgraph.c (compute_ltrans_boundary): When alias is in the > boundary, > add its target too. > * lto.c (add_references_to_partition): Add also aliased nodes. > (add_cgraph_node_to_partition, > add_varpool_node_to_partition): Work on nodes, not functions/variables; > when adding alias, add also the aliased object. > * gcc.dg/lto/pr52634_1.c: New testcase. > * gcc.dg/lto/pr52634_0.c: New testcase.
Hi Jan, Can you backport it to 4.7? It also fixes: http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53768 Thanks. -- H.J.
