[Bug middle-end/64225] -funsafe-math-optimizations generates call to pow where multiply instruction would do

[ktkachov at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64225

--- Comment #6 from ktkachov at gcc dot gnu.org ---
fold-const.c has a comment in the relevant case that says:
 /* Canonicalize x*x as pow(x,2.0), which is expanded as x*x.  */

So we should look at why is it not being expanded as such unless
-fno-math-errno