https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66741
Richard Biener <rguenth at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|UNCONFIRMED |NEW Last reconfirmed| |2015-07-02 Ever confirmed|0 |1 --- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> --- Loop fusion is not implemented also strcpy is expanded inline too late (during RTL expansion) and thus the two loops are exposed too late for the place where it would be implemented. Same reason for not vectorizing __builtin_tolower - it's expanded too late.