[Bug middle-end/79665] gcc's signed (x*x)/200 is slower than clang's

[jistone at redhat dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79665

--- Comment #3 from Josh Stone <jistone at redhat dot com> ---
I'm using just -O3, and then I compared effects with and without -fwrapv to
figure out what's going on.  Clang is only faster without -fwrapv.

With -march=native on my Sandy Bridge, a few instructions are placed in a
different order, but it's otherwise identical.