Yeah, I didn't show all of it, sorry. My patch to address this problem includes a more detailed description (http://gcc.gnu.org/ml/gcc-patches/2005-05/msg00127.html).
As of right now, I don't think this is a VRP problem, but something wrong with the tree Ada produces. Configure a compiler for target i386-pc-linux-gnu (or any other i386 variant, not sure if it occurs elsewhere) and compile ada/sem_intr.adb with: I'm out of town until tomorrow and will do this then.