CCS: Expressions window --- identifier not found?

Tool/software: Code Composer Studio

Can someone tell me why tst will not populate in the expressions window with a value but rather "identifier not found: tst" ?

#include <msp430.h>
#include <string.h>

void main(void)
{
    char a[] = "Hello";

    unsigned int tst;
    tst = strlen(a);
    if (tst < 8)
        LPM3;
    else
        LPM0;
}