bug500 (missed optimization)

Percentage Accurate: 69.6% → 98.6%
Time: 6.7s
Alternatives: 6
Speedup: 6.5×

Specification

?
\[-1000 < x \land x < 1000\]
\[\begin{array}{l} \\ \sin x - x \end{array} \]
(FPCore (x) :precision binary64 (- (sin x) x))
double code(double x) {
	return sin(x) - x;
}
real(8) function code(x)
    real(8), intent (in) :: x
    code = sin(x) - x
end function
public static double code(double x) {
	return Math.sin(x) - x;
}
def code(x):
	return math.sin(x) - x
function code(x)
	return Float64(sin(x) - x)
end
function tmp = code(x)
	tmp = sin(x) - x;
end
code[x_] := N[(N[Sin[x], $MachinePrecision] - x), $MachinePrecision]
\begin{array}{l}

\\
\sin x - x
\end{array}

Sampling outcomes in binary64 precision:

Local Percentage Accuracy vs ?

The average percentage accuracy by input value. Horizontal axis shows value of an input variable; the variable is choosen in the title. Vertical axis is accuracy; higher is better. Red represent the original program, while blue represents Herbie's suggestion. These can be toggled with buttons below the plot. The line is an average while dots represent individual samples.

Accuracy vs Speed?

Herbie found 6 alternatives:

AlternativeAccuracySpeedup
The accuracy (vertical axis) and speed (horizontal axis) of each alternatives. Up and to the right is better. The red square shows the initial program, and each blue circle shows an alternative.The line shows the best available speed-accuracy tradeoffs.

Initial Program: 69.6% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \sin x - x \end{array} \]
(FPCore (x) :precision binary64 (- (sin x) x))
double code(double x) {
	return sin(x) - x;
}
real(8) function code(x)
    real(8), intent (in) :: x
    code = sin(x) - x
end function
public static double code(double x) {
	return Math.sin(x) - x;
}
def code(x):
	return math.sin(x) - x
function code(x)
	return Float64(sin(x) - x)
end
function tmp = code(x)
	tmp = sin(x) - x;
end
code[x_] := N[(N[Sin[x], $MachinePrecision] - x), $MachinePrecision]
\begin{array}{l}

\\
\sin x - x
\end{array}

Alternative 1: 98.6% accurate, 0.5× speedup?

\[\begin{array}{l} \\ \mathsf{fma}\left({x}^{4}, -0.0001984126984126984, \left(x \cdot x\right) \cdot 0.008333333333333333 - 0.16666666666666666\right) \cdot {x}^{3} \end{array} \]
(FPCore (x)
 :precision binary64
 (*
  (fma
   (pow x 4.0)
   -0.0001984126984126984
   (- (* (* x x) 0.008333333333333333) 0.16666666666666666))
  (pow x 3.0)))
double code(double x) {
	return fma(pow(x, 4.0), -0.0001984126984126984, (((x * x) * 0.008333333333333333) - 0.16666666666666666)) * pow(x, 3.0);
}
function code(x)
	return Float64(fma((x ^ 4.0), -0.0001984126984126984, Float64(Float64(Float64(x * x) * 0.008333333333333333) - 0.16666666666666666)) * (x ^ 3.0))
end
code[x_] := N[(N[(N[Power[x, 4.0], $MachinePrecision] * -0.0001984126984126984 + N[(N[(N[(x * x), $MachinePrecision] * 0.008333333333333333), $MachinePrecision] - 0.16666666666666666), $MachinePrecision]), $MachinePrecision] * N[Power[x, 3.0], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\mathsf{fma}\left({x}^{4}, -0.0001984126984126984, \left(x \cdot x\right) \cdot 0.008333333333333333 - 0.16666666666666666\right) \cdot {x}^{3}
\end{array}
Derivation
  1. Initial program 70.4%

    \[\sin x - x \]
  2. Add Preprocessing
  3. Taylor expanded in x around 0

    \[\leadsto \color{blue}{{x}^{3} \cdot \left({x}^{2} \cdot \left(\frac{1}{120} + \frac{-1}{5040} \cdot {x}^{2}\right) - \frac{1}{6}\right)} \]
  4. Step-by-step derivation
    1. *-commutativeN/A

      \[\leadsto \color{blue}{\left({x}^{2} \cdot \left(\frac{1}{120} + \frac{-1}{5040} \cdot {x}^{2}\right) - \frac{1}{6}\right) \cdot {x}^{3}} \]
    2. lower-*.f64N/A

      \[\leadsto \color{blue}{\left({x}^{2} \cdot \left(\frac{1}{120} + \frac{-1}{5040} \cdot {x}^{2}\right) - \frac{1}{6}\right) \cdot {x}^{3}} \]
    3. +-commutativeN/A

      \[\leadsto \left({x}^{2} \cdot \color{blue}{\left(\frac{-1}{5040} \cdot {x}^{2} + \frac{1}{120}\right)} - \frac{1}{6}\right) \cdot {x}^{3} \]
    4. distribute-lft-inN/A

      \[\leadsto \left(\color{blue}{\left({x}^{2} \cdot \left(\frac{-1}{5040} \cdot {x}^{2}\right) + {x}^{2} \cdot \frac{1}{120}\right)} - \frac{1}{6}\right) \cdot {x}^{3} \]
    5. *-commutativeN/A

      \[\leadsto \left(\left({x}^{2} \cdot \left(\frac{-1}{5040} \cdot {x}^{2}\right) + \color{blue}{\frac{1}{120} \cdot {x}^{2}}\right) - \frac{1}{6}\right) \cdot {x}^{3} \]
    6. associate--l+N/A

      \[\leadsto \color{blue}{\left({x}^{2} \cdot \left(\frac{-1}{5040} \cdot {x}^{2}\right) + \left(\frac{1}{120} \cdot {x}^{2} - \frac{1}{6}\right)\right)} \cdot {x}^{3} \]
    7. *-commutativeN/A

      \[\leadsto \left({x}^{2} \cdot \color{blue}{\left({x}^{2} \cdot \frac{-1}{5040}\right)} + \left(\frac{1}{120} \cdot {x}^{2} - \frac{1}{6}\right)\right) \cdot {x}^{3} \]
    8. associate-*r*N/A

      \[\leadsto \left(\color{blue}{\left({x}^{2} \cdot {x}^{2}\right) \cdot \frac{-1}{5040}} + \left(\frac{1}{120} \cdot {x}^{2} - \frac{1}{6}\right)\right) \cdot {x}^{3} \]
    9. lower-fma.f64N/A

      \[\leadsto \color{blue}{\mathsf{fma}\left({x}^{2} \cdot {x}^{2}, \frac{-1}{5040}, \frac{1}{120} \cdot {x}^{2} - \frac{1}{6}\right)} \cdot {x}^{3} \]
    10. pow-sqrN/A

      \[\leadsto \mathsf{fma}\left(\color{blue}{{x}^{\left(2 \cdot 2\right)}}, \frac{-1}{5040}, \frac{1}{120} \cdot {x}^{2} - \frac{1}{6}\right) \cdot {x}^{3} \]
    11. lower-pow.f64N/A

      \[\leadsto \mathsf{fma}\left(\color{blue}{{x}^{\left(2 \cdot 2\right)}}, \frac{-1}{5040}, \frac{1}{120} \cdot {x}^{2} - \frac{1}{6}\right) \cdot {x}^{3} \]
    12. metadata-evalN/A

      \[\leadsto \mathsf{fma}\left({x}^{\color{blue}{4}}, \frac{-1}{5040}, \frac{1}{120} \cdot {x}^{2} - \frac{1}{6}\right) \cdot {x}^{3} \]
    13. lower--.f64N/A

      \[\leadsto \mathsf{fma}\left({x}^{4}, \frac{-1}{5040}, \color{blue}{\frac{1}{120} \cdot {x}^{2} - \frac{1}{6}}\right) \cdot {x}^{3} \]
    14. *-commutativeN/A

      \[\leadsto \mathsf{fma}\left({x}^{4}, \frac{-1}{5040}, \color{blue}{{x}^{2} \cdot \frac{1}{120}} - \frac{1}{6}\right) \cdot {x}^{3} \]
    15. lower-*.f64N/A

      \[\leadsto \mathsf{fma}\left({x}^{4}, \frac{-1}{5040}, \color{blue}{{x}^{2} \cdot \frac{1}{120}} - \frac{1}{6}\right) \cdot {x}^{3} \]
    16. unpow2N/A

      \[\leadsto \mathsf{fma}\left({x}^{4}, \frac{-1}{5040}, \color{blue}{\left(x \cdot x\right)} \cdot \frac{1}{120} - \frac{1}{6}\right) \cdot {x}^{3} \]
    17. lower-*.f64N/A

      \[\leadsto \mathsf{fma}\left({x}^{4}, \frac{-1}{5040}, \color{blue}{\left(x \cdot x\right)} \cdot \frac{1}{120} - \frac{1}{6}\right) \cdot {x}^{3} \]
    18. lower-pow.f6499.4

      \[\leadsto \mathsf{fma}\left({x}^{4}, -0.0001984126984126984, \left(x \cdot x\right) \cdot 0.008333333333333333 - 0.16666666666666666\right) \cdot \color{blue}{{x}^{3}} \]
  5. Applied rewrites99.4%

    \[\leadsto \color{blue}{\mathsf{fma}\left({x}^{4}, -0.0001984126984126984, \left(x \cdot x\right) \cdot 0.008333333333333333 - 0.16666666666666666\right) \cdot {x}^{3}} \]
  6. Final simplification99.4%

    \[\leadsto \mathsf{fma}\left({x}^{4}, -0.0001984126984126984, \left(x \cdot x\right) \cdot 0.008333333333333333 - 0.16666666666666666\right) \cdot {x}^{3} \]
  7. Add Preprocessing

Alternative 2: 98.6% accurate, 2.6× speedup?

\[\begin{array}{l} \\ \left(\left(x \cdot x\right) \cdot \mathsf{fma}\left(-0.0001984126984126984 \cdot x, x, 0.008333333333333333\right) - 0.16666666666666666\right) \cdot \left(\left(x \cdot x\right) \cdot x\right) \end{array} \]
(FPCore (x)
 :precision binary64
 (*
  (-
   (* (* x x) (fma (* -0.0001984126984126984 x) x 0.008333333333333333))
   0.16666666666666666)
  (* (* x x) x)))
double code(double x) {
	return (((x * x) * fma((-0.0001984126984126984 * x), x, 0.008333333333333333)) - 0.16666666666666666) * ((x * x) * x);
}
function code(x)
	return Float64(Float64(Float64(Float64(x * x) * fma(Float64(-0.0001984126984126984 * x), x, 0.008333333333333333)) - 0.16666666666666666) * Float64(Float64(x * x) * x))
end
code[x_] := N[(N[(N[(N[(x * x), $MachinePrecision] * N[(N[(-0.0001984126984126984 * x), $MachinePrecision] * x + 0.008333333333333333), $MachinePrecision]), $MachinePrecision] - 0.16666666666666666), $MachinePrecision] * N[(N[(x * x), $MachinePrecision] * x), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\left(\left(x \cdot x\right) \cdot \mathsf{fma}\left(-0.0001984126984126984 \cdot x, x, 0.008333333333333333\right) - 0.16666666666666666\right) \cdot \left(\left(x \cdot x\right) \cdot x\right)
\end{array}
Derivation
  1. Initial program 70.4%

    \[\sin x - x \]
  2. Add Preprocessing
  3. Taylor expanded in x around 0

    \[\leadsto \color{blue}{{x}^{3} \cdot \left({x}^{2} \cdot \left(\frac{1}{120} + \frac{-1}{5040} \cdot {x}^{2}\right) - \frac{1}{6}\right)} \]
  4. Step-by-step derivation
    1. *-commutativeN/A

      \[\leadsto \color{blue}{\left({x}^{2} \cdot \left(\frac{1}{120} + \frac{-1}{5040} \cdot {x}^{2}\right) - \frac{1}{6}\right) \cdot {x}^{3}} \]
    2. lower-*.f64N/A

      \[\leadsto \color{blue}{\left({x}^{2} \cdot \left(\frac{1}{120} + \frac{-1}{5040} \cdot {x}^{2}\right) - \frac{1}{6}\right) \cdot {x}^{3}} \]
    3. +-commutativeN/A

      \[\leadsto \left({x}^{2} \cdot \color{blue}{\left(\frac{-1}{5040} \cdot {x}^{2} + \frac{1}{120}\right)} - \frac{1}{6}\right) \cdot {x}^{3} \]
    4. distribute-lft-inN/A

      \[\leadsto \left(\color{blue}{\left({x}^{2} \cdot \left(\frac{-1}{5040} \cdot {x}^{2}\right) + {x}^{2} \cdot \frac{1}{120}\right)} - \frac{1}{6}\right) \cdot {x}^{3} \]
    5. *-commutativeN/A

      \[\leadsto \left(\left({x}^{2} \cdot \left(\frac{-1}{5040} \cdot {x}^{2}\right) + \color{blue}{\frac{1}{120} \cdot {x}^{2}}\right) - \frac{1}{6}\right) \cdot {x}^{3} \]
    6. associate--l+N/A

      \[\leadsto \color{blue}{\left({x}^{2} \cdot \left(\frac{-1}{5040} \cdot {x}^{2}\right) + \left(\frac{1}{120} \cdot {x}^{2} - \frac{1}{6}\right)\right)} \cdot {x}^{3} \]
    7. *-commutativeN/A

      \[\leadsto \left({x}^{2} \cdot \color{blue}{\left({x}^{2} \cdot \frac{-1}{5040}\right)} + \left(\frac{1}{120} \cdot {x}^{2} - \frac{1}{6}\right)\right) \cdot {x}^{3} \]
    8. associate-*r*N/A

      \[\leadsto \left(\color{blue}{\left({x}^{2} \cdot {x}^{2}\right) \cdot \frac{-1}{5040}} + \left(\frac{1}{120} \cdot {x}^{2} - \frac{1}{6}\right)\right) \cdot {x}^{3} \]
    9. lower-fma.f64N/A

      \[\leadsto \color{blue}{\mathsf{fma}\left({x}^{2} \cdot {x}^{2}, \frac{-1}{5040}, \frac{1}{120} \cdot {x}^{2} - \frac{1}{6}\right)} \cdot {x}^{3} \]
    10. pow-sqrN/A

      \[\leadsto \mathsf{fma}\left(\color{blue}{{x}^{\left(2 \cdot 2\right)}}, \frac{-1}{5040}, \frac{1}{120} \cdot {x}^{2} - \frac{1}{6}\right) \cdot {x}^{3} \]
    11. lower-pow.f64N/A

      \[\leadsto \mathsf{fma}\left(\color{blue}{{x}^{\left(2 \cdot 2\right)}}, \frac{-1}{5040}, \frac{1}{120} \cdot {x}^{2} - \frac{1}{6}\right) \cdot {x}^{3} \]
    12. metadata-evalN/A

      \[\leadsto \mathsf{fma}\left({x}^{\color{blue}{4}}, \frac{-1}{5040}, \frac{1}{120} \cdot {x}^{2} - \frac{1}{6}\right) \cdot {x}^{3} \]
    13. lower--.f64N/A

      \[\leadsto \mathsf{fma}\left({x}^{4}, \frac{-1}{5040}, \color{blue}{\frac{1}{120} \cdot {x}^{2} - \frac{1}{6}}\right) \cdot {x}^{3} \]
    14. *-commutativeN/A

      \[\leadsto \mathsf{fma}\left({x}^{4}, \frac{-1}{5040}, \color{blue}{{x}^{2} \cdot \frac{1}{120}} - \frac{1}{6}\right) \cdot {x}^{3} \]
    15. lower-*.f64N/A

      \[\leadsto \mathsf{fma}\left({x}^{4}, \frac{-1}{5040}, \color{blue}{{x}^{2} \cdot \frac{1}{120}} - \frac{1}{6}\right) \cdot {x}^{3} \]
    16. unpow2N/A

      \[\leadsto \mathsf{fma}\left({x}^{4}, \frac{-1}{5040}, \color{blue}{\left(x \cdot x\right)} \cdot \frac{1}{120} - \frac{1}{6}\right) \cdot {x}^{3} \]
    17. lower-*.f64N/A

      \[\leadsto \mathsf{fma}\left({x}^{4}, \frac{-1}{5040}, \color{blue}{\left(x \cdot x\right)} \cdot \frac{1}{120} - \frac{1}{6}\right) \cdot {x}^{3} \]
    18. lower-pow.f6499.4

      \[\leadsto \mathsf{fma}\left({x}^{4}, -0.0001984126984126984, \left(x \cdot x\right) \cdot 0.008333333333333333 - 0.16666666666666666\right) \cdot \color{blue}{{x}^{3}} \]
  5. Applied rewrites99.4%

    \[\leadsto \color{blue}{\mathsf{fma}\left({x}^{4}, -0.0001984126984126984, \left(x \cdot x\right) \cdot 0.008333333333333333 - 0.16666666666666666\right) \cdot {x}^{3}} \]
  6. Step-by-step derivation
    1. Applied rewrites99.4%

      \[\leadsto \mathsf{fma}\left({x}^{4}, -0.0001984126984126984, \left(x \cdot x\right) \cdot 0.008333333333333333 - 0.16666666666666666\right) \cdot \left(\left(x \cdot x\right) \cdot \color{blue}{x}\right) \]
    2. Step-by-step derivation
      1. Applied rewrites99.4%

        \[\leadsto \left(\mathsf{fma}\left(0.008333333333333333, x \cdot x, -0.0001984126984126984 \cdot {x}^{4}\right) - 0.16666666666666666\right) \cdot \left(\color{blue}{\left(x \cdot x\right)} \cdot x\right) \]
      2. Step-by-step derivation
        1. Applied rewrites99.4%

          \[\leadsto \left(\left(x \cdot x\right) \cdot \mathsf{fma}\left(-0.0001984126984126984 \cdot x, x, 0.008333333333333333\right) - 0.16666666666666666\right) \cdot \left(\color{blue}{\left(x \cdot x\right)} \cdot x\right) \]
        2. Final simplification99.4%

          \[\leadsto \left(\left(x \cdot x\right) \cdot \mathsf{fma}\left(-0.0001984126984126984 \cdot x, x, 0.008333333333333333\right) - 0.16666666666666666\right) \cdot \left(\left(x \cdot x\right) \cdot x\right) \]
        3. Add Preprocessing

        Alternative 3: 98.3% accurate, 3.9× speedup?

        \[\begin{array}{l} \\ \left(\mathsf{fma}\left(0.008333333333333333, x \cdot x, -0.16666666666666666\right) \cdot \left(x \cdot x\right)\right) \cdot x \end{array} \]
        (FPCore (x)
         :precision binary64
         (* (* (fma 0.008333333333333333 (* x x) -0.16666666666666666) (* x x)) x))
        double code(double x) {
        	return (fma(0.008333333333333333, (x * x), -0.16666666666666666) * (x * x)) * x;
        }
        
        function code(x)
        	return Float64(Float64(fma(0.008333333333333333, Float64(x * x), -0.16666666666666666) * Float64(x * x)) * x)
        end
        
        code[x_] := N[(N[(N[(0.008333333333333333 * N[(x * x), $MachinePrecision] + -0.16666666666666666), $MachinePrecision] * N[(x * x), $MachinePrecision]), $MachinePrecision] * x), $MachinePrecision]
        
        \begin{array}{l}
        
        \\
        \left(\mathsf{fma}\left(0.008333333333333333, x \cdot x, -0.16666666666666666\right) \cdot \left(x \cdot x\right)\right) \cdot x
        \end{array}
        
        Derivation
        1. Initial program 70.4%

          \[\sin x - x \]
        2. Add Preprocessing
        3. Taylor expanded in x around 0

          \[\leadsto \color{blue}{{x}^{3} \cdot \left({x}^{2} \cdot \left(\frac{1}{120} + \frac{-1}{5040} \cdot {x}^{2}\right) - \frac{1}{6}\right)} \]
        4. Step-by-step derivation
          1. *-commutativeN/A

            \[\leadsto \color{blue}{\left({x}^{2} \cdot \left(\frac{1}{120} + \frac{-1}{5040} \cdot {x}^{2}\right) - \frac{1}{6}\right) \cdot {x}^{3}} \]
          2. lower-*.f64N/A

            \[\leadsto \color{blue}{\left({x}^{2} \cdot \left(\frac{1}{120} + \frac{-1}{5040} \cdot {x}^{2}\right) - \frac{1}{6}\right) \cdot {x}^{3}} \]
          3. +-commutativeN/A

            \[\leadsto \left({x}^{2} \cdot \color{blue}{\left(\frac{-1}{5040} \cdot {x}^{2} + \frac{1}{120}\right)} - \frac{1}{6}\right) \cdot {x}^{3} \]
          4. distribute-lft-inN/A

            \[\leadsto \left(\color{blue}{\left({x}^{2} \cdot \left(\frac{-1}{5040} \cdot {x}^{2}\right) + {x}^{2} \cdot \frac{1}{120}\right)} - \frac{1}{6}\right) \cdot {x}^{3} \]
          5. *-commutativeN/A

            \[\leadsto \left(\left({x}^{2} \cdot \left(\frac{-1}{5040} \cdot {x}^{2}\right) + \color{blue}{\frac{1}{120} \cdot {x}^{2}}\right) - \frac{1}{6}\right) \cdot {x}^{3} \]
          6. associate--l+N/A

            \[\leadsto \color{blue}{\left({x}^{2} \cdot \left(\frac{-1}{5040} \cdot {x}^{2}\right) + \left(\frac{1}{120} \cdot {x}^{2} - \frac{1}{6}\right)\right)} \cdot {x}^{3} \]
          7. *-commutativeN/A

            \[\leadsto \left({x}^{2} \cdot \color{blue}{\left({x}^{2} \cdot \frac{-1}{5040}\right)} + \left(\frac{1}{120} \cdot {x}^{2} - \frac{1}{6}\right)\right) \cdot {x}^{3} \]
          8. associate-*r*N/A

            \[\leadsto \left(\color{blue}{\left({x}^{2} \cdot {x}^{2}\right) \cdot \frac{-1}{5040}} + \left(\frac{1}{120} \cdot {x}^{2} - \frac{1}{6}\right)\right) \cdot {x}^{3} \]
          9. lower-fma.f64N/A

            \[\leadsto \color{blue}{\mathsf{fma}\left({x}^{2} \cdot {x}^{2}, \frac{-1}{5040}, \frac{1}{120} \cdot {x}^{2} - \frac{1}{6}\right)} \cdot {x}^{3} \]
          10. pow-sqrN/A

            \[\leadsto \mathsf{fma}\left(\color{blue}{{x}^{\left(2 \cdot 2\right)}}, \frac{-1}{5040}, \frac{1}{120} \cdot {x}^{2} - \frac{1}{6}\right) \cdot {x}^{3} \]
          11. lower-pow.f64N/A

            \[\leadsto \mathsf{fma}\left(\color{blue}{{x}^{\left(2 \cdot 2\right)}}, \frac{-1}{5040}, \frac{1}{120} \cdot {x}^{2} - \frac{1}{6}\right) \cdot {x}^{3} \]
          12. metadata-evalN/A

            \[\leadsto \mathsf{fma}\left({x}^{\color{blue}{4}}, \frac{-1}{5040}, \frac{1}{120} \cdot {x}^{2} - \frac{1}{6}\right) \cdot {x}^{3} \]
          13. lower--.f64N/A

            \[\leadsto \mathsf{fma}\left({x}^{4}, \frac{-1}{5040}, \color{blue}{\frac{1}{120} \cdot {x}^{2} - \frac{1}{6}}\right) \cdot {x}^{3} \]
          14. *-commutativeN/A

            \[\leadsto \mathsf{fma}\left({x}^{4}, \frac{-1}{5040}, \color{blue}{{x}^{2} \cdot \frac{1}{120}} - \frac{1}{6}\right) \cdot {x}^{3} \]
          15. lower-*.f64N/A

            \[\leadsto \mathsf{fma}\left({x}^{4}, \frac{-1}{5040}, \color{blue}{{x}^{2} \cdot \frac{1}{120}} - \frac{1}{6}\right) \cdot {x}^{3} \]
          16. unpow2N/A

            \[\leadsto \mathsf{fma}\left({x}^{4}, \frac{-1}{5040}, \color{blue}{\left(x \cdot x\right)} \cdot \frac{1}{120} - \frac{1}{6}\right) \cdot {x}^{3} \]
          17. lower-*.f64N/A

            \[\leadsto \mathsf{fma}\left({x}^{4}, \frac{-1}{5040}, \color{blue}{\left(x \cdot x\right)} \cdot \frac{1}{120} - \frac{1}{6}\right) \cdot {x}^{3} \]
          18. lower-pow.f6499.4

            \[\leadsto \mathsf{fma}\left({x}^{4}, -0.0001984126984126984, \left(x \cdot x\right) \cdot 0.008333333333333333 - 0.16666666666666666\right) \cdot \color{blue}{{x}^{3}} \]
        5. Applied rewrites99.4%

          \[\leadsto \color{blue}{\mathsf{fma}\left({x}^{4}, -0.0001984126984126984, \left(x \cdot x\right) \cdot 0.008333333333333333 - 0.16666666666666666\right) \cdot {x}^{3}} \]
        6. Taylor expanded in x around 0

          \[\leadsto \color{blue}{{x}^{3} \cdot \left(\frac{1}{120} \cdot {x}^{2} - \frac{1}{6}\right)} \]
        7. Step-by-step derivation
          1. *-commutativeN/A

            \[\leadsto \color{blue}{\left(\frac{1}{120} \cdot {x}^{2} - \frac{1}{6}\right) \cdot {x}^{3}} \]
          2. lower-*.f64N/A

            \[\leadsto \color{blue}{\left(\frac{1}{120} \cdot {x}^{2} - \frac{1}{6}\right) \cdot {x}^{3}} \]
          3. metadata-evalN/A

            \[\leadsto \left(\frac{1}{120} \cdot {x}^{2} - \color{blue}{\frac{1}{6} \cdot 1}\right) \cdot {x}^{3} \]
          4. metadata-evalN/A

            \[\leadsto \left(\frac{1}{120} \cdot {x}^{2} - \color{blue}{\left(\mathsf{neg}\left(\frac{-1}{6}\right)\right)} \cdot 1\right) \cdot {x}^{3} \]
          5. lft-mult-inverseN/A

            \[\leadsto \left(\frac{1}{120} \cdot {x}^{2} - \left(\mathsf{neg}\left(\frac{-1}{6}\right)\right) \cdot \color{blue}{\left(\frac{1}{{x}^{2}} \cdot {x}^{2}\right)}\right) \cdot {x}^{3} \]
          6. fp-cancel-sign-sub-invN/A

            \[\leadsto \color{blue}{\left(\frac{1}{120} \cdot {x}^{2} + \frac{-1}{6} \cdot \left(\frac{1}{{x}^{2}} \cdot {x}^{2}\right)\right)} \cdot {x}^{3} \]
          7. associate-*l*N/A

            \[\leadsto \left(\frac{1}{120} \cdot {x}^{2} + \color{blue}{\left(\frac{-1}{6} \cdot \frac{1}{{x}^{2}}\right) \cdot {x}^{2}}\right) \cdot {x}^{3} \]
          8. metadata-evalN/A

            \[\leadsto \left(\frac{1}{120} \cdot {x}^{2} + \left(\color{blue}{\left(\mathsf{neg}\left(\frac{1}{6}\right)\right)} \cdot \frac{1}{{x}^{2}}\right) \cdot {x}^{2}\right) \cdot {x}^{3} \]
          9. metadata-evalN/A

            \[\leadsto \left(\frac{1}{120} \cdot {x}^{2} + \left(\color{blue}{\frac{-1}{6}} \cdot \frac{1}{{x}^{2}}\right) \cdot {x}^{2}\right) \cdot {x}^{3} \]
          10. associate-*l*N/A

            \[\leadsto \left(\frac{1}{120} \cdot {x}^{2} + \color{blue}{\frac{-1}{6} \cdot \left(\frac{1}{{x}^{2}} \cdot {x}^{2}\right)}\right) \cdot {x}^{3} \]
          11. lft-mult-inverseN/A

            \[\leadsto \left(\frac{1}{120} \cdot {x}^{2} + \frac{-1}{6} \cdot \color{blue}{1}\right) \cdot {x}^{3} \]
          12. metadata-evalN/A

            \[\leadsto \left(\frac{1}{120} \cdot {x}^{2} + \color{blue}{\frac{-1}{6}}\right) \cdot {x}^{3} \]
          13. *-commutativeN/A

            \[\leadsto \left(\color{blue}{{x}^{2} \cdot \frac{1}{120}} + \frac{-1}{6}\right) \cdot {x}^{3} \]
          14. lower-fma.f64N/A

            \[\leadsto \color{blue}{\mathsf{fma}\left({x}^{2}, \frac{1}{120}, \frac{-1}{6}\right)} \cdot {x}^{3} \]
          15. unpow2N/A

            \[\leadsto \mathsf{fma}\left(\color{blue}{x \cdot x}, \frac{1}{120}, \frac{-1}{6}\right) \cdot {x}^{3} \]
          16. lower-*.f64N/A

            \[\leadsto \mathsf{fma}\left(\color{blue}{x \cdot x}, \frac{1}{120}, \frac{-1}{6}\right) \cdot {x}^{3} \]
          17. lower-pow.f6499.3

            \[\leadsto \mathsf{fma}\left(x \cdot x, 0.008333333333333333, -0.16666666666666666\right) \cdot \color{blue}{{x}^{3}} \]
        8. Applied rewrites99.3%

          \[\leadsto \color{blue}{\mathsf{fma}\left(x \cdot x, 0.008333333333333333, -0.16666666666666666\right) \cdot {x}^{3}} \]
        9. Step-by-step derivation
          1. Applied rewrites99.3%

            \[\leadsto \left(\mathsf{fma}\left(0.008333333333333333, x \cdot x, -0.16666666666666666\right) \cdot \left(x \cdot x\right)\right) \cdot \color{blue}{x} \]
          2. Final simplification99.3%

            \[\leadsto \left(\mathsf{fma}\left(0.008333333333333333, x \cdot x, -0.16666666666666666\right) \cdot \left(x \cdot x\right)\right) \cdot x \]
          3. Add Preprocessing

          Alternative 4: 98.3% accurate, 3.9× speedup?

          \[\begin{array}{l} \\ \mathsf{fma}\left(x \cdot x, 0.008333333333333333, -0.16666666666666666\right) \cdot \left(\left(x \cdot x\right) \cdot x\right) \end{array} \]
          (FPCore (x)
           :precision binary64
           (* (fma (* x x) 0.008333333333333333 -0.16666666666666666) (* (* x x) x)))
          double code(double x) {
          	return fma((x * x), 0.008333333333333333, -0.16666666666666666) * ((x * x) * x);
          }
          
          function code(x)
          	return Float64(fma(Float64(x * x), 0.008333333333333333, -0.16666666666666666) * Float64(Float64(x * x) * x))
          end
          
          code[x_] := N[(N[(N[(x * x), $MachinePrecision] * 0.008333333333333333 + -0.16666666666666666), $MachinePrecision] * N[(N[(x * x), $MachinePrecision] * x), $MachinePrecision]), $MachinePrecision]
          
          \begin{array}{l}
          
          \\
          \mathsf{fma}\left(x \cdot x, 0.008333333333333333, -0.16666666666666666\right) \cdot \left(\left(x \cdot x\right) \cdot x\right)
          \end{array}
          
          Derivation
          1. Initial program 70.4%

            \[\sin x - x \]
          2. Add Preprocessing
          3. Taylor expanded in x around 0

            \[\leadsto \color{blue}{{x}^{3} \cdot \left({x}^{2} \cdot \left(\frac{1}{120} + \frac{-1}{5040} \cdot {x}^{2}\right) - \frac{1}{6}\right)} \]
          4. Step-by-step derivation
            1. *-commutativeN/A

              \[\leadsto \color{blue}{\left({x}^{2} \cdot \left(\frac{1}{120} + \frac{-1}{5040} \cdot {x}^{2}\right) - \frac{1}{6}\right) \cdot {x}^{3}} \]
            2. lower-*.f64N/A

              \[\leadsto \color{blue}{\left({x}^{2} \cdot \left(\frac{1}{120} + \frac{-1}{5040} \cdot {x}^{2}\right) - \frac{1}{6}\right) \cdot {x}^{3}} \]
            3. +-commutativeN/A

              \[\leadsto \left({x}^{2} \cdot \color{blue}{\left(\frac{-1}{5040} \cdot {x}^{2} + \frac{1}{120}\right)} - \frac{1}{6}\right) \cdot {x}^{3} \]
            4. distribute-lft-inN/A

              \[\leadsto \left(\color{blue}{\left({x}^{2} \cdot \left(\frac{-1}{5040} \cdot {x}^{2}\right) + {x}^{2} \cdot \frac{1}{120}\right)} - \frac{1}{6}\right) \cdot {x}^{3} \]
            5. *-commutativeN/A

              \[\leadsto \left(\left({x}^{2} \cdot \left(\frac{-1}{5040} \cdot {x}^{2}\right) + \color{blue}{\frac{1}{120} \cdot {x}^{2}}\right) - \frac{1}{6}\right) \cdot {x}^{3} \]
            6. associate--l+N/A

              \[\leadsto \color{blue}{\left({x}^{2} \cdot \left(\frac{-1}{5040} \cdot {x}^{2}\right) + \left(\frac{1}{120} \cdot {x}^{2} - \frac{1}{6}\right)\right)} \cdot {x}^{3} \]
            7. *-commutativeN/A

              \[\leadsto \left({x}^{2} \cdot \color{blue}{\left({x}^{2} \cdot \frac{-1}{5040}\right)} + \left(\frac{1}{120} \cdot {x}^{2} - \frac{1}{6}\right)\right) \cdot {x}^{3} \]
            8. associate-*r*N/A

              \[\leadsto \left(\color{blue}{\left({x}^{2} \cdot {x}^{2}\right) \cdot \frac{-1}{5040}} + \left(\frac{1}{120} \cdot {x}^{2} - \frac{1}{6}\right)\right) \cdot {x}^{3} \]
            9. lower-fma.f64N/A

              \[\leadsto \color{blue}{\mathsf{fma}\left({x}^{2} \cdot {x}^{2}, \frac{-1}{5040}, \frac{1}{120} \cdot {x}^{2} - \frac{1}{6}\right)} \cdot {x}^{3} \]
            10. pow-sqrN/A

              \[\leadsto \mathsf{fma}\left(\color{blue}{{x}^{\left(2 \cdot 2\right)}}, \frac{-1}{5040}, \frac{1}{120} \cdot {x}^{2} - \frac{1}{6}\right) \cdot {x}^{3} \]
            11. lower-pow.f64N/A

              \[\leadsto \mathsf{fma}\left(\color{blue}{{x}^{\left(2 \cdot 2\right)}}, \frac{-1}{5040}, \frac{1}{120} \cdot {x}^{2} - \frac{1}{6}\right) \cdot {x}^{3} \]
            12. metadata-evalN/A

              \[\leadsto \mathsf{fma}\left({x}^{\color{blue}{4}}, \frac{-1}{5040}, \frac{1}{120} \cdot {x}^{2} - \frac{1}{6}\right) \cdot {x}^{3} \]
            13. lower--.f64N/A

              \[\leadsto \mathsf{fma}\left({x}^{4}, \frac{-1}{5040}, \color{blue}{\frac{1}{120} \cdot {x}^{2} - \frac{1}{6}}\right) \cdot {x}^{3} \]
            14. *-commutativeN/A

              \[\leadsto \mathsf{fma}\left({x}^{4}, \frac{-1}{5040}, \color{blue}{{x}^{2} \cdot \frac{1}{120}} - \frac{1}{6}\right) \cdot {x}^{3} \]
            15. lower-*.f64N/A

              \[\leadsto \mathsf{fma}\left({x}^{4}, \frac{-1}{5040}, \color{blue}{{x}^{2} \cdot \frac{1}{120}} - \frac{1}{6}\right) \cdot {x}^{3} \]
            16. unpow2N/A

              \[\leadsto \mathsf{fma}\left({x}^{4}, \frac{-1}{5040}, \color{blue}{\left(x \cdot x\right)} \cdot \frac{1}{120} - \frac{1}{6}\right) \cdot {x}^{3} \]
            17. lower-*.f64N/A

              \[\leadsto \mathsf{fma}\left({x}^{4}, \frac{-1}{5040}, \color{blue}{\left(x \cdot x\right)} \cdot \frac{1}{120} - \frac{1}{6}\right) \cdot {x}^{3} \]
            18. lower-pow.f6499.4

              \[\leadsto \mathsf{fma}\left({x}^{4}, -0.0001984126984126984, \left(x \cdot x\right) \cdot 0.008333333333333333 - 0.16666666666666666\right) \cdot \color{blue}{{x}^{3}} \]
          5. Applied rewrites99.4%

            \[\leadsto \color{blue}{\mathsf{fma}\left({x}^{4}, -0.0001984126984126984, \left(x \cdot x\right) \cdot 0.008333333333333333 - 0.16666666666666666\right) \cdot {x}^{3}} \]
          6. Step-by-step derivation
            1. Applied rewrites99.4%

              \[\leadsto \mathsf{fma}\left({x}^{4}, -0.0001984126984126984, \left(x \cdot x\right) \cdot 0.008333333333333333 - 0.16666666666666666\right) \cdot \left(\left(x \cdot x\right) \cdot \color{blue}{x}\right) \]
            2. Taylor expanded in x around 0

              \[\leadsto \left(\frac{1}{120} \cdot {x}^{2} - \frac{1}{6}\right) \cdot \left(\color{blue}{\left(x \cdot x\right)} \cdot x\right) \]
            3. Step-by-step derivation
              1. Applied rewrites99.2%

                \[\leadsto \mathsf{fma}\left(x \cdot x, 0.008333333333333333, -0.16666666666666666\right) \cdot \left(\color{blue}{\left(x \cdot x\right)} \cdot x\right) \]
              2. Final simplification99.2%

                \[\leadsto \mathsf{fma}\left(x \cdot x, 0.008333333333333333, -0.16666666666666666\right) \cdot \left(\left(x \cdot x\right) \cdot x\right) \]
              3. Add Preprocessing

              Alternative 5: 98.0% accurate, 6.5× speedup?

              \[\begin{array}{l} \\ x \cdot \left(\left(x \cdot x\right) \cdot -0.16666666666666666\right) \end{array} \]
              (FPCore (x) :precision binary64 (* x (* (* x x) -0.16666666666666666)))
              double code(double x) {
              	return x * ((x * x) * -0.16666666666666666);
              }
              
              real(8) function code(x)
                  real(8), intent (in) :: x
                  code = x * ((x * x) * (-0.16666666666666666d0))
              end function
              
              public static double code(double x) {
              	return x * ((x * x) * -0.16666666666666666);
              }
              
              def code(x):
              	return x * ((x * x) * -0.16666666666666666)
              
              function code(x)
              	return Float64(x * Float64(Float64(x * x) * -0.16666666666666666))
              end
              
              function tmp = code(x)
              	tmp = x * ((x * x) * -0.16666666666666666);
              end
              
              code[x_] := N[(x * N[(N[(x * x), $MachinePrecision] * -0.16666666666666666), $MachinePrecision]), $MachinePrecision]
              
              \begin{array}{l}
              
              \\
              x \cdot \left(\left(x \cdot x\right) \cdot -0.16666666666666666\right)
              \end{array}
              
              Derivation
              1. Initial program 70.4%

                \[\sin x - x \]
              2. Add Preprocessing
              3. Taylor expanded in x around 0

                \[\leadsto \color{blue}{\frac{-1}{6} \cdot {x}^{3}} \]
              4. Step-by-step derivation
                1. *-commutativeN/A

                  \[\leadsto \color{blue}{{x}^{3} \cdot \frac{-1}{6}} \]
                2. lower-*.f64N/A

                  \[\leadsto \color{blue}{{x}^{3} \cdot \frac{-1}{6}} \]
                3. lower-pow.f6498.8

                  \[\leadsto \color{blue}{{x}^{3}} \cdot -0.16666666666666666 \]
              5. Applied rewrites98.8%

                \[\leadsto \color{blue}{{x}^{3} \cdot -0.16666666666666666} \]
              6. Step-by-step derivation
                1. Applied rewrites98.8%

                  \[\leadsto x \cdot \color{blue}{\left(\left(x \cdot x\right) \cdot -0.16666666666666666\right)} \]
                2. Final simplification98.8%

                  \[\leadsto x \cdot \left(\left(x \cdot x\right) \cdot -0.16666666666666666\right) \]
                3. Add Preprocessing

                Alternative 6: 67.1% accurate, 104.0× speedup?

                \[\begin{array}{l} \\ 0 \end{array} \]
                (FPCore (x) :precision binary64 0.0)
                double code(double x) {
                	return 0.0;
                }
                
                real(8) function code(x)
                    real(8), intent (in) :: x
                    code = 0.0d0
                end function
                
                public static double code(double x) {
                	return 0.0;
                }
                
                def code(x):
                	return 0.0
                
                function code(x)
                	return 0.0
                end
                
                function tmp = code(x)
                	tmp = 0.0;
                end
                
                code[x_] := 0.0
                
                \begin{array}{l}
                
                \\
                0
                \end{array}
                
                Derivation
                1. Initial program 70.4%

                  \[\sin x - x \]
                2. Add Preprocessing
                3. Applied rewrites4.7%

                  \[\leadsto \color{blue}{\mathsf{fma}\left(\sqrt{-x}, \sqrt{-x}, \sin x\right)} \]
                4. Taylor expanded in x around 0

                  \[\leadsto \color{blue}{x \cdot \left(1 + {\left(\sqrt{-1}\right)}^{2}\right)} \]
                5. Step-by-step derivation
                  1. unpow2N/A

                    \[\leadsto x \cdot \left(1 + \color{blue}{\sqrt{-1} \cdot \sqrt{-1}}\right) \]
                  2. rem-square-sqrtN/A

                    \[\leadsto x \cdot \left(1 + \color{blue}{-1}\right) \]
                  3. metadata-evalN/A

                    \[\leadsto x \cdot \color{blue}{0} \]
                  4. mul0-rgt68.8

                    \[\leadsto \color{blue}{0} \]
                6. Applied rewrites68.8%

                  \[\leadsto \color{blue}{0} \]
                7. Add Preprocessing

                Developer Target 1: 99.8% accurate, 0.3× speedup?

                \[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\left|x\right| < 0.07:\\ \;\;\;\;-\left(\left(\frac{{x}^{3}}{6} - \frac{{x}^{5}}{120}\right) + \frac{{x}^{7}}{5040}\right)\\ \mathbf{else}:\\ \;\;\;\;\sin x - x\\ \end{array} \end{array} \]
                (FPCore (x)
                 :precision binary64
                 (if (< (fabs x) 0.07)
                   (- (+ (- (/ (pow x 3.0) 6.0) (/ (pow x 5.0) 120.0)) (/ (pow x 7.0) 5040.0)))
                   (- (sin x) x)))
                double code(double x) {
                	double tmp;
                	if (fabs(x) < 0.07) {
                		tmp = -(((pow(x, 3.0) / 6.0) - (pow(x, 5.0) / 120.0)) + (pow(x, 7.0) / 5040.0));
                	} else {
                		tmp = sin(x) - x;
                	}
                	return tmp;
                }
                
                real(8) function code(x)
                    real(8), intent (in) :: x
                    real(8) :: tmp
                    if (abs(x) < 0.07d0) then
                        tmp = -((((x ** 3.0d0) / 6.0d0) - ((x ** 5.0d0) / 120.0d0)) + ((x ** 7.0d0) / 5040.0d0))
                    else
                        tmp = sin(x) - x
                    end if
                    code = tmp
                end function
                
                public static double code(double x) {
                	double tmp;
                	if (Math.abs(x) < 0.07) {
                		tmp = -(((Math.pow(x, 3.0) / 6.0) - (Math.pow(x, 5.0) / 120.0)) + (Math.pow(x, 7.0) / 5040.0));
                	} else {
                		tmp = Math.sin(x) - x;
                	}
                	return tmp;
                }
                
                def code(x):
                	tmp = 0
                	if math.fabs(x) < 0.07:
                		tmp = -(((math.pow(x, 3.0) / 6.0) - (math.pow(x, 5.0) / 120.0)) + (math.pow(x, 7.0) / 5040.0))
                	else:
                		tmp = math.sin(x) - x
                	return tmp
                
                function code(x)
                	tmp = 0.0
                	if (abs(x) < 0.07)
                		tmp = Float64(-Float64(Float64(Float64((x ^ 3.0) / 6.0) - Float64((x ^ 5.0) / 120.0)) + Float64((x ^ 7.0) / 5040.0)));
                	else
                		tmp = Float64(sin(x) - x);
                	end
                	return tmp
                end
                
                function tmp_2 = code(x)
                	tmp = 0.0;
                	if (abs(x) < 0.07)
                		tmp = -((((x ^ 3.0) / 6.0) - ((x ^ 5.0) / 120.0)) + ((x ^ 7.0) / 5040.0));
                	else
                		tmp = sin(x) - x;
                	end
                	tmp_2 = tmp;
                end
                
                code[x_] := If[Less[N[Abs[x], $MachinePrecision], 0.07], (-N[(N[(N[(N[Power[x, 3.0], $MachinePrecision] / 6.0), $MachinePrecision] - N[(N[Power[x, 5.0], $MachinePrecision] / 120.0), $MachinePrecision]), $MachinePrecision] + N[(N[Power[x, 7.0], $MachinePrecision] / 5040.0), $MachinePrecision]), $MachinePrecision]), N[(N[Sin[x], $MachinePrecision] - x), $MachinePrecision]]
                
                \begin{array}{l}
                
                \\
                \begin{array}{l}
                \mathbf{if}\;\left|x\right| < 0.07:\\
                \;\;\;\;-\left(\left(\frac{{x}^{3}}{6} - \frac{{x}^{5}}{120}\right) + \frac{{x}^{7}}{5040}\right)\\
                
                \mathbf{else}:\\
                \;\;\;\;\sin x - x\\
                
                
                \end{array}
                \end{array}
                

                Reproduce

                ?
                herbie shell --seed 2024332 
                (FPCore (x)
                  :name "bug500 (missed optimization)"
                  :precision binary64
                  :pre (and (< -1000.0 x) (< x 1000.0))
                
                  :alt
                  (! :herbie-platform default (if (< (fabs x) 7/100) (- (+ (- (/ (pow x 3) 6) (/ (pow x 5) 120)) (/ (pow x 7) 5040))) (- (sin x) x)))
                
                  (- (sin x) x))