Re:Making the obvious code fast (2016)
by steveklabnik on Wednesday April 17, 2019 @02:56PM
(#19685383)
The rust approach to this kind of this is not to use global flags to control this kind of behavior, but to use wrapping types to get the behavior on the spots where you want it: https://crates.io/crates/fast-floats
rust has no way to pass ffast-math flag (unless that changed recently) which will enable this for C/C++