[Bug rtl-optimization/46238] New: s390x bootstrap problem: wrong code generated due to crossjumping

[krebbel at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46238

           Summary: s390x bootstrap problem: wrong code generated due to
                    crossjumping
           Product: gcc
           Version: 4.6.0
            Status: UNCONFIRMED
          Severity: critical
          Priority: P3
         Component: rtl-optimization
        AssignedTo: unassig...@gcc.gnu.org
        ReportedBy: kreb...@gcc.gnu.org


collect2 gets miscompiled due to a bug in cfgcleanup.

try_head_merge_bb moves an insn setting r2 over an insn clobbering that
register. DCE removes the set afterwards. try_head_merge_bb doesn't notice due
to wrong live info in the 'live_union' variable.

Proposed fix:
http://gcc.gnu.org/ml/gcc-patches/2010-10/msg02569.html