Nicholas Clark wrote in perl.perl6.internals : > >> > r->score = r->use_count + (r->lhs_use_count << 2); >> > >> > r->score += 1 << (loop_depth * 3); [...] > I wonder how hard it would be to make a --fsummon-nasal-demons flag for gcc > that added trap code for all classes of undefined behaviour, and caused > code to abort (or something more colourfully "undefined") if anything > undefined gets executed. I realise that code would run very slowly, but it > would be a very very useful debugging tool.
What undefined behaviour are you referring to exactly ? the shift overrun ? AFAIK it's very predictable (given one int size). Cases of potential undefined behavior can usually be detected at compile-time. I imagine that shift overrun detection can be enabled via an ugly macro and a cpp symbol. (what's a nasal demon ? can't find the nasald(8) manpage)
