Can someone tell me why it's not possible to integrate the following?

$\displaystyle \int_{-\infty}^x e^{-\frac{1}{2}x^2}dx$

What's wrong with $\displaystyle -\frac{1}{x}e^{-\frac{1}{2}x^2}$ evaluated from $\displaystyle -\infty$ to $\displaystyle x$ ?