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

As the updated question will show ;) , the problem exists with a std::vector. One common error with vectors is reserve()ing what should have been resize()d. As a result, you'd be writing outside array bounds. An optimizer may discard those writes.