https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61338
--- Comment #3 from Marc Glisse <glisse at gcc dot gnu.org> --- Possibly easier is the case of a reduction, where permutations are clearly irrelevant. int f(int*arr,int size){ int sum=0; for(int i = 0; i < size; i++){ sum += arr[size-1-i]; } return sum; } We still have a VEC_PERM_EXPR in the hot loop before accumulating. (by the way, we accumulate in a variable of type "vector(4) int", while I would expect "vector(4) unsigned int" for overflow reasons)