Revert "Remove option to disable vectorization"
This mostly reverts !980 (merged), which might still be desirable on more recent APUs.
Slightly updated the text and left in the warning fix from !980 (merged).
r? @dkazakov
Edited by Laurențiu Nicola
This mostly reverts !980 (merged), which might still be desirable on more recent APUs.
Slightly updated the text and left in the warning fix from !980 (merged).
r? @dkazakov