[PATCH] D21127: Remove redundant FMUL in Newton-Raphson SQRT code

[Nikolai Bozhenov via llvm-commits]

n.bozhenov added a comment.

Here are the results with vfmadd132ss:

                                     est1         est2
  Total tests:                 2130706432   2130706432
  Inexact results:              911966111    817657369
  Estimate missed by  1 ULP:    854798052    785288244
  Estimate missed by  2 ULP:     56073347     32117919
  Estimate missed by  3 ULP:      1092044       251206
  Estimate missed by  4 ULP:         2668            0
  Estimate missed by >4 ULP:            0            0

Generally, using FMA improves precision. Again, the new code
sequence produces statistically better results.


http://reviews.llvm.org/D21127