> No it isn't. The results should still be the same. You aren't considering call ABI or PIC issues. Natives might have different call-saved registers, or global fixed register (like the TLS pointers), that affect optimization in different ways than an embedded (no tls, different pic, different ABI) compile would.
Consider, for example, DJGPP vs Win32. They're both essentially i386-COFF targets, but the resulting code is quite different.