I have tested this code with many version of GCC, three under Linux x86 PC and one into x86 Mac OS X.
This bug appears with version 3.4.5 (Gentoo 3.4.5, ssp-3.4.5-1.0, pie-8.7.9), in a Gentoo x86_64 Linux PC, and with Gcc 4.1.2 (Ubuntu 4.1.2-0ubuntu4) and 4.1.2 20061115 (prerelease) (Debian 4.1.1-21).
It doesn't appear in x86 Mac Os X 10.4 with "version 4.0.1 (Apple Computer, Inc. build 5250)"

This very simple code show the gcc's bug.

#include <stdio.h> // for printf

struct ELT {
  int item;
} one_elt;


int main()
{ struct ELT *two_elt;
  long *src,*dst;

  
  two_elt = malloc(sizeof(struct ELT));

  
  src = (long *)&one_elt;
  dst = (long *)two_elt;

  dst[0] = src[0];

  two_elt->item = 27;

  malloc(2);

  printf("27 = %d\n",two_elt->item);
  return( 0);
}

When you compile with -O1 or -O0, we get "27=27", but when we compile with -O2 or -O3 switch, we get "27=0"
Gcc "forget" code's dependancy.