I linked an example [1] in a parallel reply that shows gcc (and clang) doing it at -O3 without PGO, for the case of possibly overlapping arrays. --- [1] https

I linked an example [1] in a parallel reply that shows gcc (and clang) doing it at -O3 without PGO, for the case of possibly overlapping arrays. --- [1] https://godbolt.org/z/9vZfl_ https://godbolt.org/z/9vZfl_