I'm going to say no.
In assembly that's just a difference of conditional jumps. JE vs. JNE (Jump if Equal, Jump if Not Equal)
This is what VC6 output:
Code:
while (!done)
0040117C mov eax,dword ptr [ebp-4]
0040117F and eax,0FFh
00401184 test eax,eax
00401186 jne main+48h
Code:
while (notdone)
0040117C mov eax,dword ptr [ebp-4]
0040117F and eax,0FFh
00401184 test eax,eax
00401186 je main+48h
As you can see, the only difference between the two is the different jumps. I doubt one is any faster than the other.