C undefined behavior fix

<<So, I would claim that the case is symetric with writing volatiles. If the standard doesn't make a distinction for write v read, then you can't and claim that distinction is based in the standard. If you claim the standard does make a distinction, please point it out, I am unaware of it.

Well obviously you do not go writing to other variables, but if you have three variables IN ONE PROGRAM

a
b
c

adjacently allocated, and b is volatile, and a/c are not, then your argument *so far* would appear to allow a compiler to do an "over-wide" load for b. If you think otherwise, please prove from standard.

Of course a write is generally not at all symmetrical, since you don't want a write to be to clobber a and c (yes yes, I know you could still construct a far out case in which a and b might be stored together, and indeed that is a legitimate separate discussion).