As far as i can telll, the only reason for this being here is to make the iterators work. I've attached a partial patch to remove it, but it needs some work. I don't have time to work on it more for a while
-- Summary: ssa_use_operand_d using 30 bytes in struct tree_phi_arg Product: gcc Version: 4.1.0 Status: UNCONFIRMED Severity: normal Priority: P2 Component: tree-optimization AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: dberlin at gcc dot gnu dot org CC: gcc-bugs at gcc dot gnu dot org http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23938