Bluaegh

const long long iterCount = pow(2, 29);
for(long long i = 0; i<iterCount; ++i)
{
    if(i < 0)
    {
        ++x; // x is 32 or 64 bits (different disassembly below)
    }
}

// Incrementing x as a 32-bit value

00E3140D C5 F9 13 44 24 18    vmovlpd     qword ptr [esp+18h],xmm0
00E31413 85 FF                test        edi,edi
00E31415 7C 29                jl          main+1A0h (0E31440h)
00E31417 7F 04                jg          main+17Dh (0E3141Dh)
00E31419 85 F6                test        esi,esi
00E3141B 74 23                je          main+1A0h (0E31440h)
00E3141D 8B 4C 24 1C          mov         ecx,dword ptr [esp+1Ch]
00E31421 8B 44 24 18          mov         eax,dword ptr [esp+18h]
00E31425 85 C9                test        ecx,ecx
00E31427 7F 07                jg          main+190h (0E31430h)
00E31429 7C 04                jl          main+18Fh (0E3142Fh)
00E3142B 85 C0                test        eax,eax
00E3142D 73 01                jae         main+190h (0E31430h)
00E3142F 43                   inc         ebx
00E31430 83 C0 01             add         eax,1
00E31433 83 D1 00             adc         ecx,0
00E31436 3B CF                cmp         ecx,edi
00E31438 7C EB                jl          main+185h (0E31425h)
00E3143A 7F 04                jg          main+1A0h (0E31440h)
00E3143C 3B C6                cmp         eax,esi
00E3143E 72 E5                jb          main+185h (0E31425h)

// Incrementing x as a 64-bit value

00EB144B C5 F9 13 44 24 18    vmovlpd     qword ptr [esp+18h],xmm0
00EB1451 85 FF                test        edi,edi
00EB1453 7C 41                jl          main+1F6h (0EB1496h)
00EB1455 7F 04                jg          main+1BBh (0EB145Bh)
00EB1457 85 F6                test        esi,esi
00EB1459 74 3B                je          main+1F6h (0EB1496h)
00EB145B 8B 54 24 10          mov         edx,dword ptr [esp+10h]
00EB145F 8B 5C 24 14          mov         ebx,dword ptr [esp+14h]
00EB1463 8B 4C 24 1C          mov         ecx,dword ptr [esp+1Ch]
00EB1467 8B 44 24 18          mov         eax,dword ptr [esp+18h]
00EB146B 89 54 24 0C          mov         dword ptr [esp+0Ch],edx
00EB146F 90                   nop
00EB1470 85 C9                test        ecx,ecx
00EB1472 7F 10                jg          main+1E4h (0EB1484h)
00EB1474 7C 04                jl          main+1DAh (0EB147Ah)
00EB1476 85 C0                test        eax,eax
00EB1478 73 0A                jae         main+1E4h (0EB1484h)
00EB147A 83 C2 01             add         edx,1
00EB147D 89 54 24 0C          mov         dword ptr [esp+0Ch],edx
00EB1481 83 D3 00             adc         ebx,0
00EB1484 83 C0 01             add         eax,1
00EB1487 83 D1 00             adc         ecx,0
00EB148A 3B CF                cmp         ecx,edi
00EB148C 7C E2                jl          main+1D0h (0EB1470h)
00EB148E 7F 12                jg          main+202h (0EB14A2h)
00EB1490 3B C6                cmp         eax,esi
00EB1492 72 DC                jb          main+1D0h (0EB1470h)
00EB1494 EB 0C                jmp         main+202h (0EB14A2h)
00EB1496 8B 44 24 10          mov         eax,dword ptr [esp+10h]
00EB149A 8B 5C 24 14          mov         ebx,dword ptr [esp+14h]
00EB149E 89 44 24 0C          mov         dword ptr [esp+0Ch],eax