another -Wunsequenced topic

[David Chisnall]

On 9 Jul 2013, at 05:40, Tim Kientzle <tim at kientzle.com> wrote:

> However, this does have an implicit redundant store,
> so changing it to
> 
>    ptr = func(ptr + 1);
> 
> is still a good idea, just not for the reason Clang was claiming.

If the compiler can tell that ptr has not escaped, then it will elide the redundant store (typically, it will be gone as long as ptr is a local and its address has not been passed out of the function), so there should be no change to the generated code.

However, I still agree that it is good style, because if I read the original code I would be left wondering what the original programmer expected the incremented value of ptr++ to be visible to and suspect a more subtle error.  

David

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