SLP vectorizer turned on in commit r190916 which says nothing about it - how to turn it off?

Revision 190916

Commit message:

"Lift alignment restrictions for load/store folding on VINSERTF128/VEXTRACTF128. Fixes PR17268."

Actual contents of the commit includes

Index: tools/opt/opt.cpp

This looks like it was an oversight; there is already a -vectorize-slp option exported by the PassManagerBuilder that should control this default.