[Bug tree-optimization/88315] SAD and DOT_PROD SLP reductions with initial value != 0 create wrong code

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88315

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|---                         |FIXED
      Known to fail|                            |7.4.1

--- Comment #5 from Richard Biener <rguenth at gcc dot gnu.org> ---
Too much refactoring makes backporting this for GCC 7 too risky.  The function
to patch there would anyone run into this is vect_get_constant_vectors.

So - fixed for GCC 8+.