Average Error: 0.0 → 0
Time: 539.0ms
Precision: 64
\[x \cdot y - x\]
↓
\[\mathsf{fma}\left(x, y, -x\right)\]
x \cdot y - x
↓
\mathsf{fma}\left(x, y, -x\right)
double f(double x, double y) {
        double r174648 = x;
        double r174649 = y;
        double r174650 = r174648 * r174649;
        double r174651 = r174650 - r174648;
        return r174651;
}
↓
double f(double x, double y) {
        double r174652 = x;
        double r174653 = y;
        double r174654 = -r174652;
        double r174655 = fma(r174652, r174653, r174654);
        return r174655;
}

Error

Bits error versus x

Bits error versus y

Derivation

  1. Initial program 0.0

    \[x \cdot y - x\]
  2. Using strategy rm

  3. Applied fma-neg0

    \[\leadsto \color{blue}{\mathsf{fma}\left(x, y, -x\right)}\]

  4. Final simplification0

    \[\leadsto \mathsf{fma}\left(x, y, -x\right)\]

Reproduce

herbie shell --seed 2020018 +o rules:numerics
(FPCore (x y)
  :name "Data.Histogram.Bin.LogBinD:$cbinSizeN from histogram-fill-0.8.4.1"
  :precision binary64
  (- (* x y) x))