[pcwalton]

I'm also skeptical about the often-claimed superiority of ICC. The numbers I've seen are very equivocal.

Besides, it's irrelevant: there are lots of free C compilers that don't exploit UB, and also rarely get used.

[rurban]

Lots? None are usable to replace our current insane compilers, removing code without warnings.

None of pgcc, sdcc, tcc, lcc and friends work with current code bases, plus they have severe bugs.