[Bug c++/39981] New: zero-size base class optimization fails in certain scenarios

["navinkumar+bugs at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>]

Scenario1A: When class X inherits from A, B, and C;  and A and C are empty
classes, then gcc properly creates X such that: sizeof(X) == sizeof(B)

Scenario1B: When class X inherits from A and B;  and A is an empty class, then
gcc properly creates X such that: sizeof(X) == sizeof(B)

Scenario2A: When class X inherits from A, B, and C;  and A and C are empty
classes inheriting from another empty class, then gcc IMPROPERLY creates X such
that: sizeof(X) > sizeof(B)

Scenario2B: When class X is a composite of A and B;  and A is an empty class
inheriting from another empty class, then gcc properly creates X such that:
sizeof(X) == sizeof(B)


-- 
           Summary: zero-size base class optimization fails in certain
                    scenarios
           Product: gcc
           Version: 4.4.0
            Status: UNCONFIRMED
          Severity: critical
          Priority: P3
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: navinkumar+bugs at gmail dot com


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39981