[Bug tree-optimization/68976] [6 Regression] ICE w/ -O2 (and above) -fgraphite-identity (or -floop-nest-optimize)

[vries at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68976

--- Comment #8 from vries at gcc dot gnu.org ---
Created attachment 37344
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=37344&action=edit
tentative patch