mpl 1.5.3 and 2.0, py3.6
_xs = np.linspace(-50, 50, 1001); plt.semilogy(scipy.stats.norm.pdf(_xs))
results in

where zero values (due to floating point resolution limits, at the edges) get ignored, as expected, but
_xs = np.linspace(-50, 50, 1001); plt.plot(scipy.stats.norm.pdf(_xs))
plt.gcf().canvas.draw()
plt.gca().set(yscale="log")
results in the incorrect

mpl 1.5.3 and 2.0, py3.6
results in

where zero values (due to floating point resolution limits, at the edges) get ignored, as expected, but
results in the incorrect
