the iphone code optimization problem

I use XCode develop an App for ipad, the code write in c++

When I use optimiza开发者_StackOverflowtion level (None -O0 ) the app run normal ... When I use optimization level (fastest,smallest -Os) the app will crash by one pointer point to an useless address？

What's the problem?

Thanks !

You have a bug in your code; somewhere, you will be relying on undefined behaviour. This sort of thing may only cause a problem in certain circumstances, such as changing compiler flags.

You will have to debug your code.