[Bug tree-optimization/87859] [8/9 Regression] store-merging miscompilation of mesa

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87859

--- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Created attachment 44948
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=44948&action=edit
gcc9-pr87859.patch

WIP patch.