[Bug lto/54839] New: INTEGER_CST is missed by uniuqify_nodes and soaks tons of memory

["hubicka at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54839

             Bug #: 54839
           Summary: INTEGER_CST is missed by uniuqify_nodes and soaks tons
                    of memory
    Classification: Unclassified
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: lto
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: hubicka@gcc.gnu.org


Created attachment 28377
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=28377
patch

Because integer_cst is streamed directly, it bypasses streamer cache. It
however reffers to types and the types needs fixup.
The attached patch provokes the problem by ggc_freeing the obsoletted types and
also fixes it by adding to_fix vector. I wonder what is better option?
Do we need to stream them differently? I guess integer_csts are often 0/1 and
streaming always the whole thing seems wasteful.