1. Nice!
2.
....
804bc26: 0f 0b ud2a
....
804bd1f: 83 f8 02 cmp $0x2,%eax
804bd22: 0f 87 63 01 00 00 ja 804be8b <main+0xecb>
804bd28: 83 f8 03 cmp $0x3,%eax
804bd2b: 0f 87 f5 fe ff ff ja 804bc26 <main+0xc66>
....
Thats what i get for defensiv coding? 
(after the first couple instances of stuff like this i stopped grepping for ud2a
and it's addresses)
3.
Can clang/llvm use into (the only conditional trap on x86) for such things?
Or int3? Should give a:
SIGTRAP 5 Core Trace/breakpoint trap
Or drop you into the debugger.
Greetings
Jan