How does one diff binary files?

[Scott Le Grand]

Hi, in the continuing saga to figure out what my program looks like, I have
been re-compiling my program to try and make it match the compiled version
I have saved.  However, I have found that two linkings of the same set of
object files results in them being different when diff is applied to
them.  What is going on here?  The program is in C at level 2 optimization.

Scott Le Grand