It is a local variable, so it should be either in a register or on stack. None of them is initialized. If the code does not contain any assignment of an absolute value (++ is a relative value) to it, it shouldn't be initialized ever and neither produce the correct result nor suppress the warning. But it is possible that the compiler uses a register for it in the inlined section, and before the first inline section, the very same register actually is initialized - in a different context. THis might suppress the warning. But then this is a bug. The count variable is not set to a specific value anywhere in the code and therefore should produce the warning, independently of a possible reuse of its storage space during the current function.
Unless I'm missing a C language specification that handles initialization of uninitialized local variables, it is just a coincidence that the program works as expected. However, that's just my opinion, and maybe someone with inside knowledge of the compiler can shed some light on it. If you see the inlined code, does count get set to 0 somewhere? And if so, why? Nobody told the compiler to do it. Or does the code just use the very same register/variable before for a count-down at whose end it is coincidentally zero? JMGross ----- Ursprüngliche Nachricht ----- Von: Michiel Konstapel An: Peter Bigot Gesendet am: 06 Jul 2011 14:11:32 Betreff: Re: [Mspgcc-users] Missing uninitialized variable warning? > Can you confirm that, in the generated code, there is actual reference > to the variable that was not initialized? Let me check... It ends up inlined several levels deep, so I couldn't find it in the objdump output. So I figured I'd __noinline__ the fuction, and hey: I do get the warning. C keeps scaring me... Does this mean that the compiler assumes I want it zeroed, and can prove it will be zero in the inlined code? Or does it assume I don't care, but it only warns me about it in some cases? Or can it simply no longer detect the error if the function is inlined? So, at no optimization, or too much optimization, you lose your warnings? ------------------------------------------------------------------------------ All of the data generated in your IT infrastructure is seriously valuable. Why? It contains a definitive record of application performance, security threats, fraudulent activity, and more. Splunk takes this data and makes sense of it. IT sense. And common sense. http://p.sf.net/sfu/splunk-d2d-c2 _______________________________________________ Mspgcc-users mailing list Mspgcc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/mspgcc-users
