I may be mistaken, but didn't GCC miscompile the Ada front end because of this VRP bug here: http://gcc.gnu.org/PR21332 ?
I'm not sure if that was it, but there was a VRP item on my plate from a few weeks ago since I claimed that it was an Ada front-end bug and not a VRP bug. Unfortunately, I got distracted and then was away. I will make a real attempt to look at it in the next few days.