Wireshark-dev: [Wireshark-dev] GCC 4.2 might cause some overflow checks not to work
From: Guy Harris <[email protected]>
Date: Wed, 09 Apr 2008 11:26:56 -0700

In short, if, for example, any code that has a pointer into a buffer and a length of an object in a buffer, and checks to make sure that the length is sane by checking that buffer+length >= buffer, that code won't work in GCC 4.2 because GCC 4.2 assumes that if you add an integer value to a pointer value, the resulting pointer value will be greater than or equal to the original pointer value, and doesn't bother checking for that.
I'm not sure whether that's an issue for integer addition; the CERT 
Secure Coding site makes recommendations other than
	foo = a + b;
	if (foo < a)

for checking whether that sum overflows: