I found this wonderful flag (-ftrapuv) which helped me determine that my huge program has some uninitialized stack variables ( producing different results with & without that flag), the question is, what can I do to find those variables? I do not know the code and it's huge.
I have every intel tool at my disposal..
Intel Inspector XE can detect some occurrences of uninitialized variables. Here's an article that describes more about how the flag -ftrapuv works: https://software.intel.com/en-us/articles/dont-optimize-when-using-ftrapuv-for-uninitialized-variable-detection