PxIFG set to 1 manaually has any behavior?

Hi, everyone:

    I found the function halProcessKeyInterrupt in file ZStack-CC2530-2.5.1a\Components\hal\target\CC2530EB\hal_key.c, 

Line 427: HAL_KEY_SW_6_PXIFG = ~(HAL_KEY_SW_6_BIT); /* Clear Interrupt Flag */

    This sample program clears a specify bit while setting other bits for PxIFG.

    It's general to clear a specify bit and keep other bits unchanged in a interrupt handler .

    The datasheet of cc2530 does not mention the behavior of this opeartion: set a bit of PxIFG to 1 manaually.

    For example , when PxIFG.0 is setting by this instruction(PxIFG.0 = 1) , will one more interrupt caused by cc2530 immediately after this interrupt handler exit(by re-enabling the CPU interrupt)or just ignore this operation by cc2530, or any other behavior?

    Does anyone know that?Thanks a lot!