[Bug middle-end/78071] -Os -ffast-math generates pow() for 1/(x*x)

[glisse at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78071

--- Comment #3 from Marc Glisse <glisse at gcc dot gnu.org> ---
Dup of PR 70777? I can reproduce with gcc-6 but not with gcc-7.