Check that double variables have the correct representation when changing...

datediff = function(date1, date2, interval) {

  var delta = 1;

  switch(interval) {

  case "day":

    delta /= 24;

  case "hour":

    delta /= 60;

  case "minute":

    delta /= 60;

  case "second":

    delta /= 1000;

  case "millisecond":

    delta *= date2.getTime() - date1.getTime();

  }

  return Math.round(delta);

};

var diff = datediff(new Date("2012-04-28T14:30:00Z"), new Date("2012-04-29T14:30:00Z"), "day"); 

for (var i = 0; i < 50; i++) {

  diff = datediff(new Date("2012-04-28T17:00:00Z"), new Date("2012-04-28T17:30:00Z"), "minute"); 

  assertEq(diff, 30);

}

        frame.assertValidRegisterState();

        a->jumpMap[uint32_t(PC - script->code)] = masm.label();

        if (cx->typeInferenceEnabled() && opinfo->safePoint) {

            /*

             * We may have come in from a table switch, which does not watch

             * for the new types introduced for variables at each dispatch

             * target. Make sure that new SSA values at this safe point with

             * double type have the correct in memory representation.

             */

            const SlotValue *newv = analysis->newValues(PC);

            if (newv) {

                while (newv->slot) {

                    if (newv->value.kind() == SSAValue::PHI &&

                        newv->value.phiOffset() == uint32_t(PC - script->code) &&

                        analysis->trackSlot(newv->slot) &&

                        a->varTypes[newv->slot].getTypeTag(cx) == JSVAL_TYPE_DOUBLE) {

                        FrameEntry *fe = frame.getSlotEntry(newv->slot);

                        masm.ensureInMemoryDouble(frame.addressOf(fe));

                    }

                    newv++;

                }

            }

        }

        // Now that we have the PC's register allocation, make sure it gets

        // explicitly updated if this is the loop entry and new loop registers

        // are allocated later on.