[Bug target/68577] [6 Regression] ICE: in expand_direct_optab_fn, at internal-fn.c:2171

[rsandifo at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68577

--- Comment #3 from rsandifo at gcc dot gnu.org <rsandifo at gcc dot gnu.org> ---
Created attachment 36870
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=36870&action=edit
proposed patch

Here's the patch I'm testing.  Adding the cost of the demotion
prevents vectorisation in the original testcase, but it vectorises
successfully with -fvect-cost-model=unlimited.  (We didn't
vectorise before the combined_fn series either.)

The patch also includes an SLP testcase.