[Bug lto/63226] New: ICE with -flto-odr-type-merging

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63226

            Bug ID: 63226
           Summary: ICE with -flto-odr-type-merging
           Product: gcc
           Version: 4.9.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: lto
          Assignee: unassigned at gcc dot gnu.org
          Reporter: burnus at gcc dot gnu.org
                CC: hubicka at gcc dot gnu.org

The ICE depends on Honza's no-yet committed patch:
https://gcc.gnu.org/ml/gcc-patches/2014-09/msg00878.html

With that patch (and hence -flto-odr-type-merging), one gets the following ICE:

$ g++ -c -flto one12.ii two10.ii
$ g++ -flto -flto-odr-type-merging one12.o two10.ii


lto1: internal compiler error: in odr_types_equivalent_p, at ipa-devirt.c:1066
0x815714 odr_types_equivalent_p
        ../../gcc/ipa-devirt.c:1066
0x815a3e add_type_duplicate
        ../../gcc/ipa-devirt.c:1116


Note: -Wodr doesn't warn for this test case.


With the files one12.ii:
----------------------------------------
class ONE;
class OneClass {
  ONE *swpmi;
  OneClass ();
};
typedef struct ynodetype_t *ynode;
typedef struct ynodetype_t {
  union {
    struct { ynode child1, child3; } i;
  } y;
} ynodetype;
class ONE {
  union _xynode { ynode yn; } ;
};
OneClass::OneClass () { }
----------------------------------------

two10.ii:
----------------------------------------
class ONE;
class TwoClass {
  ONE *swpci;
  TwoClass ();
};
typedef struct ynodetype_t *ynode;
typedef struct { } yleaftype;
typedef struct ynodetype_t {
  union {
    struct { yleaftype leaf; } i;
  } y;
} ynodetype;
typedef ynode ytree;
class ONE {
  ytree Tree;
};
TwoClass::TwoClass () { }
----------------------------------------