[Bug tree-optimization/123002] [15/16 regression] WIDEN_MULT_EXPR are incorrectly vectorized since r15-3189-gd3e71b99194bff

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=123002

--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> ---
Created attachment 62993
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=62993&action=edit
patch from my tree

This is the full patch, as said I do not expect it to fix the issue.  I'll work
on this from here.