Bug on array indexing (maybe bug on unrolled loop?)

Bug on loop unrolling?!!!!

for (unsigned int xi=0;xi<8;xi++)
{
	// GOES WRONG BLOCKSIZE STEPS (xi*8) INSTEAD OF (xi)
	float diff=image[imageAddress+xi]-average[imageAddress+xi];
	...
}

for (unsigned int xi=0;xi<8;xi++)
{
	// GOES OK 
	float diff=image[imageAddress]-average[imageAddress];
	imageAddress++;
	...
}