MSP430F5131程序调试问题

#include <msp430f5131.h>

void main(void)
{
WDTCTL = WDT_MDLY_32; // Set Watchdog Timer interval to ~30ms
IE1|= WDTIE; // Enable WDT interrupt
P1DIR |= 0x40; // Set P1.6 to output direction

_BIS_SR(LPM0_bits + GIE); // Enter LPM0 w/ interrupt
}

// Watchdog Timer interrupt service routine
#pragma vector=WDT_VECTOR
__interrupt void watchdog_timer(void)
{
P1OUT ^= 0x40; // Toggle P1.6 using exclusive-OR
}

Error[Pe020]: identifier "IE1" is undefined

是 示例程序  IE1没有定义，难道是我头文件有问题？？