[Bug middle-end/15041] New: different alignments for similar unions

["joerg dot richter at pdv-fs dot de" <gcc-bugzilla at gcc dot gnu dot org>]

// main.c

#include <stdio.h>

union union_id
{
    int i;
    double d;
};

union union_di
{
    double d;
    int i;
};

int main()
{
  printf( "alignof(double)=%d\n",   __alignof__(double) );
  printf( "alignof(union_id)=%d\n", __alignof__(union union_id) );
  printf( "alignof(union_di)=%d\n", __alignof__(union union_di) );
  return 0;
}

//////////////

$ gcc -v
Reading specs from /pdv/.tools/pkg/gcc/3.3.3/bin/../lib/gcc-lib/powerpc-ibm-
aix5.1.0.0/3.3.3/specs
Configured with: ../gcc-3.3.3/configure --prefix=/tools/pkg/gcc/3.3.3 --with-
ld=/bin/ld --with-as=/bin/as --enable-languages=c,c++
Thread model: aix
gcc version 3.3.3

$ gcc -o main main.c
$ main
alignof(double)=8
alignof(union_id)=4
alignof(union_di)=8

I think all numbers should be the same.

Verified with:
3.3.3
3.2.1
2.9-aix51-020209

-- 
           Summary: different alignments for similar unions
           Product: gcc
           Version: 3.3.3
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: middle-end
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: joerg dot richter at pdv-fs dot de
                CC: gcc-bugs at gcc dot gnu dot org
 GCC build triplet: powerpc-ibm-aix5.1.0.0
  GCC host triplet: powerpc-ibm-aix5.1.0.0
GCC target triplet: powerpc-ibm-aix5.1.0.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15041