STM32H723 GCC compiler Optimization problem

[carloV]

STM32CubeIDE 2.1.1: My program works if I choose the GCC compiler “none” optimization and it doesn’w work if I select any other optimization; anyone may help me ?

 

Thank you

[Andrew Neil]

This typically means that there is a flaw (or flaws) in your code - it’s relying on something which the C language does not guarantee.

 

Probably the commonest is omitting/forgetting volatile where it's needed.

Relying on timing of the C code is another.

 

The -Og level should give you good debuggability - see here.

You could try that …

 

Your could also try printf-style debugging to see where your code execution differs from what you intended

 

 

[carloV]

Thank you, I need the max speed...is there a fast way to identify where the problem comes ?

 

CarloV

[Andrew Neil]

No.

You’re just going to have to debug it to see what’s going wrong.

You could start with a code review to check volatile usage, timing dependencies, etc.

As well as the software debugger, use a scope or logic analyser to see what happens with/without the optimisation.