[Bug target/51843] New: ICE with LTO and attribute `dllimport'

[Bug target/51843] New: ICE with LTO and attribute `dllimport'

[d.g.gorbachev at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51843

             Bug #: 51843
           Summary: ICE with LTO and attribute `dllimport'
    Classification: Unclassified
           Product: gcc
           Version: 4.7.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: d.g.gorbachev@gmail.com
            Target: *-*-mingw32


Created attachment 26312
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=26312
Testcase

"If a symbol previously declared `dllimport' is later defined, the attribute is
ignored in subsequent references, and a warning is emitted."

GCC 4.7.0 gives this error:

In file included from :0:0:
main.c: In function 'main':
main.c:4:5: error: constant not recomputed when ADDR_EXPR changed
&bar
In file included from b.c:1:0,
                 from :1:
main.c:6:7: note: in statement
# .MEM_3 = VDEF <.MEM_2(D)>
bar = 7;

In file included from :0:0:
main.c:4:5: internal compiler error: verify_gimple failed
Please submit a full bug report,
with preprocessed source if appropriate.
See <http://gcc.gnu.org/bugs.html> for instructions.

GCC 4.6.3 just ignores the attribute, emitting no warning.

Without LTO, the two `bar's are treated as 2 different variables.

[Bug target/51843] ICE with LTO and attribute `dllimport'

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51843

Richard Guenther <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2012-01-13
     Ever Confirmed|0                           |1

--- Comment #1 from Richard Guenther <rguenth at gcc dot gnu.org> 2012-01-13 09:55:44 UTC ---
Yep.  This is because of the weird

    case VAR_DECL:
      if (((TREE_STATIC (op) || DECL_EXTERNAL (op))
           && !DECL_DLLIMPORT_P (op))

in tree.c:staticp and decl_address_ip_invariant_p which both do not make
any sense to me.

[Bug target/51843] ICE with LTO and attribute `dllimport'

[d.g.gorbachev at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=51843

--- Comment #2 from Dmitry Gorbachev <d.g.gorbachev at gmail dot com> ---
No ICE with GCC 4.9/4.10, the attribute is silently ignored.