Created attachment 12133 [details]
test case (gzipped because it's too big)

[/usr/source/Radio-TV/qttv_0.0.1/qttv] dc(1)$ gcc -v
Using built-in specs.
Target: i686-pc-linux-gnu
Configured with: ../gcc-4.1.1/configure --prefix=/usr --enable-languages=all,ada,c,c++,fortran,java,objc,obj-c++,treelang
Thread model: posix
gcc version 4.1.1
[/usr/source/Radio-TV/qttv_0.0.1/qttv] dc(1)$ gcc -O3 test.ii
test.cpp: In member function 'void tvGuide::whatsOnAt(long int, long int)':
test.cpp:15: internal compiler error: in expand_expr_addr_expr_1, at expr.c:6336
Please submit a full bug report,
with preprocessed source if appropriate.
See <URL:http://gcc.gnu.org/bugs.html> for instructions.

possibly PR 28358 and/or PR 28116

*** This bug has been marked as a duplicate of 28116 ***

Note the reduced testcase is:
struct QDateTime
{
    QDateTime addSecs( int secs ) const;
    int t;
};
QDateTime gridToDate(long x)
{
  QDateTime date;
  date = date.addSecs(1);
  return date;
}
void whatsOnAt(long x, long y)
{
  gridToDate(x);
}