GCC: program doesn't work with compilation option -O3

Question

I\'m writing a C++ program that doesn\'t work (I get a segmentation fault) when I compile it with optimizations (options -O1, -O2, -O3, etc.), but it works just fine when I

Answer 1

It is very seldom the compiler fault, but compiler do have bugs in them, and them often manifest themselves at different optimization levels (if there is a bug in an optimization pass, for example).

In general when reporting programming problems: provide a minimal code sample to demonstrate the issue, such that people can just save the code to a file, compile and run it. Make it as easy as possible to reproduce your problem.

Also, try different versions of GCC (compiling your own GCC is very easy, especially on Linux). If possible, try with another compiler. Intel C has a compiler which is more or less GCC compatible (and free for non-commercial use, I think). This will help pinpointing the problem.