I disagree. The transformation should be valid; if p is null then the result is undefined and may crash, including the rest of the program after that occurs. Ho

I disagree. The transformation should be valid; if p is null then the result is undefined and may crash, including the rest of the program after that occurs. However, I do think that it should not make such a transformation for a volatile read/write; in that case it should not make such an assumption (who knows if it is meaningful on the target computer or some sort of emulator or operating system or debugger or whatever).