How to Fix Polyspace CodeProver Orange Overflow errors

Hello,

I am getting the below Orange Overflow error due to operator *

How to fix these Overflow errors as we know this operation is not going to generate a result bigger than the datatype of int32 ?

[DGM]

Duplicate:

https://www.mathworks.com/matlabcentral/answers/2144664-how-to-fix-polyspace-codeprover-orange-warnings-due-to-operator

[Dinesh Kumar]

Hello,

Do we need to justify the errors ? or we can provide some fixes for these errors ?

[DGM]

I'm not sure what you mean by needing justification. These three questions are valid and deserve an answer, but to my understanding, they constitute three different instances of a warning message of similar form -- the tool is complaining that an arithmetic operation may cause data loss, but it isn't aware of higher-level constraints which may prevent the issue.

I don't have or use Polyspace, so I can't direcltly provide a confident answer myself. I may be blind to some details, but I estimate that a generalized answer which answers one of the questions should answer all three. If I'm wrong, someone is free to correct me. My uncertainty is why I chose to not close these two which I only think are duplicates. I'm just trying to make sure that someone more informed can see the multiplicity of questions of similar form. Hopefully someone can help you out.

Answer 1

[Akshat Dalal]

Hi Dinesh,

The unexpected orange integer overflow warning can be due to the below two reasons:

1. Shared Variable: If you are performing multitasking analysis in Polyspace, the variable 'sx32_LastMeas' could be shared. Consequently, Polyspace detects that its value might change between instances.For more information on configuring shared variables during multitasking analysis, please refer to the following documentation: www.mathworks.com/help/releases/R2020b/codeprover/ug/protections-for-shared-variables.html
2. Volatile Variable: If 'sx32_LastMeas' is declared as a Volatile variable, Polyspace treats it as a 'permanent random' variable because its value can change within its entire range between consecutive read accesses. For more information on Volatile variables in Polyspace, you can refer the following documentation: www.mathworks.com/help/releases/R2020b/polyspace_ada/ada_ref/volatile-variables.html

Therefore, if 'sx32_LastMeas' falls into either of these categories, Polyspace considers its entire range for analysis, sint32 in this case. Therefore, Polyspace reports a probable 'Integer overflow' Orange check even if it is theoretically not possible.