[Bug c/57180] New: Structures with a flexible arrray member have wrong size

[amodra at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57180



             Bug #: 57180

           Summary: Structures with a flexible arrray member have wrong

                    size

    Classification: Unclassified

           Product: gcc

           Version: 4.9.0

            Status: UNCONFIRMED

          Keywords: wrong-code

          Severity: normal

          Priority: P3

         Component: c

        AssignedTo: unassig...@gcc.gnu.org

        ReportedBy: amo...@gmail.com

                CC: algr...@acm.org, amo...@gmail.com,

                    fredrickprasha...@gmail.com, gcc-bugs@gcc.gnu.org,

                    lauro.venan...@gmail.com, qrc...@knm.org.pl,

                    sbsid...@gmail.com

        Depends on: 28865





+++ This bug was initially created as a clone of Bug #28865 +++



Cloned from 28865, because the problem is more than just getting .size wrong.

The following testcase fails on all targets at all optimization levels.

The testcase was taken from glibc/nss/nss_files/files-init.c, which is

miscompiled on powerpc or any other target using -fsection-anchors.



union

{

  struct { long j; char c[]; } s;

  char pad[32];

} x[2] =

{

  { .s = { .c = "abc123" } },

  { .s = { .c = "xyz" } }

};



int

main (void)

{

  if (sizeof (x[0]) != 32)

    __builtin_abort ();

  if (x[1].s.c[0] != 'x')

    __builtin_abort ();

  return 0;

}