http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38479
--- Comment #6 from Ionut Anghelcovici <anghelcovici at yahoo dot com> 2011-07-21 08:55:46 UTC --- The problem only occurs when the argument to a function is a 64 bit type and gcc tries to store it in r3/stack. This creates a different function prolog than the usual. The reason for this is basically that half of the value is passed in r3 (the last available register for arguments), and half of it is passed on the stack. So in this special case, the function prolog starts with: sub sp, sp, #4 The reason is that gcc wants to allocate space to store the second half of the 64 bit value on the stack as well. So it reserves these additional 4 bytes first and later writes the other part of the value passed in r3 to this location. However, the debug info generation doesn't take this special case properly into account so the debugger displays wrong info (also verified this with Trace32).
