Just a week ago I remembered reading an article several years ago about someone who ended up digging in the compiler (probably GCC) and against all odds unearth

Just a week ago I remembered reading an article several years ago about someone who ended up digging in the compiler (probably GCC) and against all odds unearthed a bug in there. As I recall it was quite involved and an interesting read but I can’t seem to find it again. If anyone has a recollection of such an article I’d be grateful to be sent a link in my general direction.