Chris, && and || are short-circuited operators that create sequence points. They are exceptions to that rule.
except where noted [e.g. special rules for && and ||], the order of evaluation of operands of individual operators and subexpressions of individual expressions, and the order in which side effects take place, is Unspecified.
This is basic stuff Chris, let's not debate the obvious, this kind of code is all over the place in the Linux kernel.
Also, where is the place in the C99 standard that details the exception? Genuinely curious. When I reviewed the standard, all that is said about the if statement is in section 22.214.171.124, and that says nothing about short circuited logic, certainly nothing about "exceptions to the rule". This seems compiler specific, but I'm happy to be shown to be wrong - if you can point me to the part in the standard.