difference in calculation result when using gcc vs Visual studio and optimisation flag

[Игорь Сотниченко]

Good afternoon!
The problem was in code part where I used the type "unsigned long" (linux 8
bytes, windows 4 bytes).
Type replaced with  "unsigned int"
Why when I have turned off the optimization  (O0)the error does not appear?

2018-04-25 16:27 GMT+05:00 Игорь Сотниченко <igor.sotnichenko@gmail.com>:

> Hello!
>
> 1.       There is a decent difference between calculations on Visual
> studio compiler and gcc 7.1 in  calculation result of my program.
>
> 2.       When optimization in gcc  are disabled, then there is no
> difference.
>
> 3.       When I have replaced O2 with keys from O1 and O2 (
> https://gcc.gnu.org/onlinedocs/gcc/Optimize-Options.html), then there is
> no difference in results, but there is a calculation speed degradation
> compared to O2.
>
>
>