[Bug rtl-optimization/89634] gmp-ecm miscompilation on s390x with -march=zEC12 -m64 -O2

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89634

--- Comment #1 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Created attachment 45927
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=45927&action=edit
gcc9-pr89634.patch

Untested fix.