https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115091
--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> --- maybe represent this in a more formal way: node = __builtin_speculate (node + 1, node->next); and in GIMPLE: _1 = node + 1; _2 = node->next; node = .SPECULATE (_1, _2); and during RTL expansion leave the desired representation to the targets which could use an UNSPEC to avoid optimizing it away. Formally we'd say __builtin_speculate "uses" the first argument if its value is equal to the second argument value. That said, I heard CPUs have prefetchers that recognize this kind of list walking. I wonder why they wouldn't then also be able to speculate the load value like you say. Oh, and doesn't this explicit speculation of using node++ open up spectre style attacks?
