Subtracts pixel values of two images I2 = I1 - I2

Hi,
Is there smart way how to subctract image I2 from I1 and place result in I2 ?

AFAIU in-place ippiSub can subtract I2 (pSsrc) from I1 (pSrcDst), but places result in I1 (pSrcDst).
When I use not-in-place subtraction and specify pSrc1=I2, pSrc2=I1, pDst=I2 will it work ? Or all 3 images must be distinct ?

Is there workaround ?