It's probably caused by some minor bugs hiding in your AC code which have not lead to visible effects due to compiler factors. It is recommended that you revise your code to fix the bugs in this case. Another possible cause is the fact that different compilers generally use different methods, libraries and settings to generate executable files. Therefore it is possible for the executable files generated by different compilers to have different efficiency or even different behaviors in some special cases. For example, the stack size of programs compiled by MS-VC++ is larger than that of those compiled by GCC/G++.