Function fadd_rz 

pub unsafe extern "C" fn fadd_rz(x: f32, y: f32) -> f32

Compute the sum of and in round-towards-zero modex. y

Nvidia docs

Returns

Returns + x. y For accuracy information for this function see the CUDA C Programming Guide, Appendix D.1, Table 6. This operation will never be merged into a single multiply-add instruction.