This is dealt with in the article - debugging optimised code is a pain, even when you know what you're doing. The source-level debugging often doesn't work, var

This is dealt with in the article - debugging optimised code is a pain, even when you know what you're doing. The source-level debugging often doesn't work, variable watches often don't work (and this even though DWARF has a whole pile of features specifically so that this stuff can work...), and debugging at the assembly language level is a chore.