[LLVMbugs] [Bug 14949] New: Struct packing doesn't work properly with -m32

[bugzilla-daemon at llvm.org]

http://llvm.org/bugs/show_bug.cgi?id=14949

             Bug #: 14949
           Summary: Struct packing doesn't work properly with -m32
           Product: clang
           Version: 3.0
          Platform: PC
        OS/Version: Linux
            Status: NEW
          Severity: normal
          Priority: P
         Component: -New Bugs
        AssignedTo: unassignedclangbugs at nondot.org
        ReportedBy: llvm at inequation.org
                CC: llvmbugs at cs.uiuc.edu
    Classification: Unclassified


Created attachment 9871
  --> http://llvm.org/bugs/attachment.cgi?id=9871
Simple program that fails to compile because of struct packing not working
properly

When cross-compiling from amd64 to i386 by using the -m32 option, struct
packing doesn't work. Attached is a simple C++ source that fails to compile.
Please also note that there is another typedef should fail (negative array
size) but does not. By commenting out the typedefs altogether you can check
that the offset of the member a is 4 and not 8.

inequation at spearhead:~$ clang pack-test.cpp -o test -m32
pack-test.cpp:6:28: error: 'equality_test' declared as an array with a negative
size
typedef char equality_test[(offsetof(test, a) == 8) ? 1 : -1];
                           ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1 error generated.
inequation at spearhead:~$ clang -v
Debian clang version 3.0-6 (tags/RELEASE_30/final) (based on LLVM 3.0)
Target: x86_64-pc-linux-gnu
Thread model: posix

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