Any cause to do a XOR EAX, EAX?

[Y.P.Y]

Why does Microsoft Visual C++ in some cases put it in codes?

Is it more efficient that mov eax, 0 ?



012B1002 in al,dx
012B1003 push ecx
int i = 5;
012B1004 mov dword ptr [i],5
return 0;
012B100B xor eax,eax



BR.

[Stikmann]

XOR EAX,EAX is only 2 bytes in length, whereas MOV EAX,0 is 3 to 6 bytes. The xor one fits better in cache.

[oOXTCOo]

and xor is faster! i had same question to sergey some time back...