> And specifically for C, unsafe optimizations are supposed to only apply with -O3. Level 2 is supposed to be safe. Citation needed? AIUI optimization levels

> And specifically for C, unsafe optimizations are supposed to only apply with -O3. Level 2 is supposed to be safe. Citation needed? AIUI optimization levels are entirely up to the compiler. GCC's man page says nothing about the safety of these levels. > Optimizations aren't supposed to change the meaning of your code. And they generally won't. The trouble is when the meaning of your code wasn't well defined to begin with (or you thought it meant something it didn't).