Here is a link to a number of suggestions I have compiled for hardening of firmware.
I'm pretty sure that a lot can be said about the list, so please post coding tips or links to pages with good information of software hardening.
iapetus.neab.net/.../hardening.html
Note that your example isn't really aliasing.
You are making a copy of a value.
But the concept of variable aliasing is when you have more than one access path to a variable. And the problem comes when the compiler isn't aware of these multiple paths.