[Bug target/77530] optimization prevents excess precision from being removed with x86/amd64 long double and rounding to 53 bits

[vincent-gcc at vinc17 dot net]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77530

--- Comment #4 from Vincent Lefèvre <vincent-gcc at vinc17 dot net> ---
Note that the current behavior should be correct on NetBSD 7. But it isn't on
NetBSD 5.1 and 6.