See the binary search code under this bug number. This code:
uMiddle = (uLeft + uRight)/2;
iDiff = pStates[uMiddle].pBase - p;
generates the code (roughly)
i = pStates + uMiddle*4 + offsetof(pBase)
j = i - p
k = j / 0
It is visible in bug.dumpraw0, so seems to be in the front end.