When I run the Valgrind Function Profiler, it says "warning, this code is not built in release mode, but this tool is intended to work with code built in Release mode, do you want to continue?". I said "yes" just to see what would happen, and it seemed incredibly more useful than when I have used the Valgrind Function Profiler with code in Release mode. Clicking on a function in the Callee/Caller/Function tables takes you to that point in the code, etc.

Why is it recommended to use the tool with Release builds only? What could go wrong with Debug builds?