[Bug middle-end/85598] [7/8/9 Regression] Incorrect warning only at -O2 and -O3

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85598

--- Comment #8 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Created attachment 45070
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=45070&action=edit
gcc9-pr85598.patch

Hack that works for me, but perhaps it is too specialized.  Can gather
statistics how many ranges it improved during bootstrap/regtest...