[Bug target/79354] [7 Regression] -mcpu=power8 -O2 generates power9 instruction on powerpc64le-linux

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79354

--- Comment #3 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Created attachment 40661
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=40661&action=edit
gcc7-pr79354.patch

Untested fix.