On Apr 20, 2011, at 2:29 AM, Ian Lance Taylor wrote: [...] > This code is accessing values of type int using a pointer of type > short*. That is invalid aliasing and your program uses undefined > behaviour. Your suggested workarounds are the right one. > > To get a warning, you could try the -Wstrict-aliasing option. I don't > think it exists in gcc 4.2, though. I tried with -Wstrict-aliasing, -Wstrict-aliasing=1..2 and -Wstrict-aliasing=3 with gcc 4.6, but didn't get a warning. This is a little bit annoying as it just happens after the implicit optimization/inlining. Declaring struct s as volatile or compiling with -fno-inline-functions helps, too. However, I'll stick with -fno-strict-aliasing. -Felix
