Detect GCC compile-time flags of a binary

Question

Is there a way to find out what gcc flags a particular binary was compiled with?

Answer 1

Experimental proof:

diciu$ gcc -O2 /tmp/tt.c -o /tmp/a.out.o2
diciu$ gcc -O3 /tmp/tt.c -o /tmp/a.out.o3
diciu$ diff /tmp/a.out.o3 /tmp/a.out.o2 
diciu$

I take that as a no as the binaries are identical.