bug366 (missed optimization)

Percentage Accurate: 45.4% → 100.0%
Time: 3.7s
Alternatives: 6
Speedup: 1.4×

Specification

?
\[\begin{array}{l} \\ \sqrt{x \cdot x + \left(y \cdot y + z \cdot z\right)} \end{array} \]
(FPCore (x y z) :precision binary64 (sqrt (+ (* x x) (+ (* y y) (* z z)))))
double code(double x, double y, double z) {
	return sqrt(((x * x) + ((y * y) + (z * z))));
}
real(8) function code(x, y, z)
    real(8), intent (in) :: x
    real(8), intent (in) :: y
    real(8), intent (in) :: z
    code = sqrt(((x * x) + ((y * y) + (z * z))))
end function
public static double code(double x, double y, double z) {
	return Math.sqrt(((x * x) + ((y * y) + (z * z))));
}
def code(x, y, z):
	return math.sqrt(((x * x) + ((y * y) + (z * z))))
function code(x, y, z)
	return sqrt(Float64(Float64(x * x) + Float64(Float64(y * y) + Float64(z * z))))
end
function tmp = code(x, y, z)
	tmp = sqrt(((x * x) + ((y * y) + (z * z))));
end
code[x_, y_, z_] := N[Sqrt[N[(N[(x * x), $MachinePrecision] + N[(N[(y * y), $MachinePrecision] + N[(z * z), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]
\begin{array}{l}

\\
\sqrt{x \cdot x + \left(y \cdot y + z \cdot z\right)}
\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: 45.4% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \sqrt{x \cdot x + \left(y \cdot y + z \cdot z\right)} \end{array} \]
(FPCore (x y z) :precision binary64 (sqrt (+ (* x x) (+ (* y y) (* z z)))))
double code(double x, double y, double z) {
	return sqrt(((x * x) + ((y * y) + (z * z))));
}
real(8) function code(x, y, z)
    real(8), intent (in) :: x
    real(8), intent (in) :: y
    real(8), intent (in) :: z
    code = sqrt(((x * x) + ((y * y) + (z * z))))
end function
public static double code(double x, double y, double z) {
	return Math.sqrt(((x * x) + ((y * y) + (z * z))));
}
def code(x, y, z):
	return math.sqrt(((x * x) + ((y * y) + (z * z))))
function code(x, y, z)
	return sqrt(Float64(Float64(x * x) + Float64(Float64(y * y) + Float64(z * z))))
end
function tmp = code(x, y, z)
	tmp = sqrt(((x * x) + ((y * y) + (z * z))));
end
code[x_, y_, z_] := N[Sqrt[N[(N[(x * x), $MachinePrecision] + N[(N[(y * y), $MachinePrecision] + N[(z * z), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]
\begin{array}{l}

\\
\sqrt{x \cdot x + \left(y \cdot y + z \cdot z\right)}
\end{array}

Alternative 1: 100.0% accurate, 0.3× speedup?

\[\begin{array}{l} z_m = \left|z\right| \\ y_m = \left|y\right| \\ x_m = \left|x\right| \\ [x_m, y_m, z_m] = \mathsf{sort}([x_m, y_m, z_m])\\ \\ \mathsf{hypot}\left(z\_m, y\_m\right) \end{array} \]
z_m = (fabs.f64 z)
y_m = (fabs.f64 y)
x_m = (fabs.f64 x)
NOTE: x_m, y_m, and z_m should be sorted in increasing order before calling this function.
(FPCore (x_m y_m z_m) :precision binary64 (hypot z_m y_m))
z_m = fabs(z);
y_m = fabs(y);
x_m = fabs(x);
assert(x_m < y_m && y_m < z_m);
double code(double x_m, double y_m, double z_m) {
	return hypot(z_m, y_m);
}
z_m = Math.abs(z);
y_m = Math.abs(y);
x_m = Math.abs(x);
assert x_m < y_m && y_m < z_m;
public static double code(double x_m, double y_m, double z_m) {
	return Math.hypot(z_m, y_m);
}
z_m = math.fabs(z)
y_m = math.fabs(y)
x_m = math.fabs(x)
[x_m, y_m, z_m] = sort([x_m, y_m, z_m])
def code(x_m, y_m, z_m):
	return math.hypot(z_m, y_m)
z_m = abs(z)
y_m = abs(y)
x_m = abs(x)
x_m, y_m, z_m = sort([x_m, y_m, z_m])
function code(x_m, y_m, z_m)
	return hypot(z_m, y_m)
end
z_m = abs(z);
y_m = abs(y);
x_m = abs(x);
x_m, y_m, z_m = num2cell(sort([x_m, y_m, z_m])){:}
function tmp = code(x_m, y_m, z_m)
	tmp = hypot(z_m, y_m);
end
z_m = N[Abs[z], $MachinePrecision]
y_m = N[Abs[y], $MachinePrecision]
x_m = N[Abs[x], $MachinePrecision]
NOTE: x_m, y_m, and z_m should be sorted in increasing order before calling this function.
code[x$95$m_, y$95$m_, z$95$m_] := N[Sqrt[z$95$m ^ 2 + y$95$m ^ 2], $MachinePrecision]
\begin{array}{l}
z_m = \left|z\right|
\\
y_m = \left|y\right|
\\
x_m = \left|x\right|
\\
[x_m, y_m, z_m] = \mathsf{sort}([x_m, y_m, z_m])\\
\\
\mathsf{hypot}\left(z\_m, y\_m\right)
\end{array}
Derivation
  1. Initial program 48.2%

    \[\sqrt{x \cdot x + \left(y \cdot y + z \cdot z\right)} \]
  2. Add Preprocessing
  3. Taylor expanded in x around 0

    \[\leadsto \color{blue}{\sqrt{{y}^{2} + {z}^{2}}} \]
  4. Step-by-step derivation
    1. +-commutativeN/A

      \[\leadsto \sqrt{\color{blue}{{z}^{2} + {y}^{2}}} \]
    2. unpow2N/A

      \[\leadsto \sqrt{\color{blue}{z \cdot z} + {y}^{2}} \]
    3. unpow2N/A

      \[\leadsto \sqrt{z \cdot z + \color{blue}{y \cdot y}} \]
    4. lower-hypot.f6467.1

      \[\leadsto \color{blue}{\mathsf{hypot}\left(z, y\right)} \]
  5. Applied rewrites67.1%

    \[\leadsto \color{blue}{\mathsf{hypot}\left(z, y\right)} \]
  6. Add Preprocessing

Alternative 2: 98.7% accurate, 1.4× speedup?

\[\begin{array}{l} z_m = \left|z\right| \\ y_m = \left|y\right| \\ x_m = \left|x\right| \\ [x_m, y_m, z_m] = \mathsf{sort}([x_m, y_m, z_m])\\ \\ \mathsf{fma}\left(\frac{x\_m}{z\_m} \cdot x\_m, 0.5, z\_m\right) \end{array} \]
z_m = (fabs.f64 z)
y_m = (fabs.f64 y)
x_m = (fabs.f64 x)
NOTE: x_m, y_m, and z_m should be sorted in increasing order before calling this function.
(FPCore (x_m y_m z_m) :precision binary64 (fma (* (/ x_m z_m) x_m) 0.5 z_m))
z_m = fabs(z);
y_m = fabs(y);
x_m = fabs(x);
assert(x_m < y_m && y_m < z_m);
double code(double x_m, double y_m, double z_m) {
	return fma(((x_m / z_m) * x_m), 0.5, z_m);
}
z_m = abs(z)
y_m = abs(y)
x_m = abs(x)
x_m, y_m, z_m = sort([x_m, y_m, z_m])
function code(x_m, y_m, z_m)
	return fma(Float64(Float64(x_m / z_m) * x_m), 0.5, z_m)
end
z_m = N[Abs[z], $MachinePrecision]
y_m = N[Abs[y], $MachinePrecision]
x_m = N[Abs[x], $MachinePrecision]
NOTE: x_m, y_m, and z_m should be sorted in increasing order before calling this function.
code[x$95$m_, y$95$m_, z$95$m_] := N[(N[(N[(x$95$m / z$95$m), $MachinePrecision] * x$95$m), $MachinePrecision] * 0.5 + z$95$m), $MachinePrecision]
\begin{array}{l}
z_m = \left|z\right|
\\
y_m = \left|y\right|
\\
x_m = \left|x\right|
\\
[x_m, y_m, z_m] = \mathsf{sort}([x_m, y_m, z_m])\\
\\
\mathsf{fma}\left(\frac{x\_m}{z\_m} \cdot x\_m, 0.5, z\_m\right)
\end{array}
Derivation
  1. Initial program 48.2%

    \[\sqrt{x \cdot x + \left(y \cdot y + z \cdot z\right)} \]
  2. Add Preprocessing
  3. Taylor expanded in z around inf

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

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

      \[\leadsto \color{blue}{\left(\frac{1}{2} \cdot \frac{{x}^{2} + {y}^{2}}{{z}^{2}} + 1\right)} \cdot z \]
    3. distribute-lft1-inN/A

      \[\leadsto \color{blue}{\left(\frac{1}{2} \cdot \frac{{x}^{2} + {y}^{2}}{{z}^{2}}\right) \cdot z + z} \]
    4. associate-*l*N/A

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

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

      \[\leadsto \color{blue}{\left(z \cdot \frac{{x}^{2} + {y}^{2}}{{z}^{2}}\right)} \cdot \frac{1}{2} + z \]
    7. associate-*r/N/A

      \[\leadsto \color{blue}{\frac{z \cdot \left({x}^{2} + {y}^{2}\right)}{{z}^{2}}} \cdot \frac{1}{2} + z \]
    8. unpow2N/A

      \[\leadsto \frac{z \cdot \left({x}^{2} + {y}^{2}\right)}{\color{blue}{z \cdot z}} \cdot \frac{1}{2} + z \]
    9. times-fracN/A

      \[\leadsto \color{blue}{\left(\frac{z}{z} \cdot \frac{{x}^{2} + {y}^{2}}{z}\right)} \cdot \frac{1}{2} + z \]
    10. *-inversesN/A

      \[\leadsto \left(\color{blue}{1} \cdot \frac{{x}^{2} + {y}^{2}}{z}\right) \cdot \frac{1}{2} + z \]
    11. associate-/l*N/A

      \[\leadsto \color{blue}{\frac{1 \cdot \left({x}^{2} + {y}^{2}\right)}{z}} \cdot \frac{1}{2} + z \]
    12. *-lft-identityN/A

      \[\leadsto \frac{\color{blue}{{x}^{2} + {y}^{2}}}{z} \cdot \frac{1}{2} + z \]
    13. lower-fma.f64N/A

      \[\leadsto \color{blue}{\mathsf{fma}\left(\frac{{x}^{2} + {y}^{2}}{z}, \frac{1}{2}, z\right)} \]
  5. Applied rewrites20.1%

    \[\leadsto \color{blue}{\mathsf{fma}\left(\frac{\mathsf{fma}\left(y, y, x \cdot x\right)}{z}, 0.5, z\right)} \]
  6. Taylor expanded in x around inf

    \[\leadsto \mathsf{fma}\left(\frac{{x}^{2}}{z}, \frac{1}{2}, z\right) \]
  7. Step-by-step derivation
    1. Applied rewrites20.5%

      \[\leadsto \mathsf{fma}\left(\frac{x \cdot x}{z}, 0.5, z\right) \]
    2. Step-by-step derivation
      1. Applied rewrites22.3%

        \[\leadsto \mathsf{fma}\left(\frac{x}{z} \cdot x, 0.5, z\right) \]
      2. Add Preprocessing

      Alternative 3: 45.4% accurate, 1.5× speedup?

      \[\begin{array}{l} z_m = \left|z\right| \\ y_m = \left|y\right| \\ x_m = \left|x\right| \\ [x_m, y_m, z_m] = \mathsf{sort}([x_m, y_m, z_m])\\ \\ \sqrt{\mathsf{fma}\left(z\_m, z\_m, y\_m \cdot y\_m\right)} \end{array} \]
      z_m = (fabs.f64 z)
      y_m = (fabs.f64 y)
      x_m = (fabs.f64 x)
      NOTE: x_m, y_m, and z_m should be sorted in increasing order before calling this function.
      (FPCore (x_m y_m z_m) :precision binary64 (sqrt (fma z_m z_m (* y_m y_m))))
      z_m = fabs(z);
      y_m = fabs(y);
      x_m = fabs(x);
      assert(x_m < y_m && y_m < z_m);
      double code(double x_m, double y_m, double z_m) {
      	return sqrt(fma(z_m, z_m, (y_m * y_m)));
      }
      
      z_m = abs(z)
      y_m = abs(y)
      x_m = abs(x)
      x_m, y_m, z_m = sort([x_m, y_m, z_m])
      function code(x_m, y_m, z_m)
      	return sqrt(fma(z_m, z_m, Float64(y_m * y_m)))
      end
      
      z_m = N[Abs[z], $MachinePrecision]
      y_m = N[Abs[y], $MachinePrecision]
      x_m = N[Abs[x], $MachinePrecision]
      NOTE: x_m, y_m, and z_m should be sorted in increasing order before calling this function.
      code[x$95$m_, y$95$m_, z$95$m_] := N[Sqrt[N[(z$95$m * z$95$m + N[(y$95$m * y$95$m), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]
      
      \begin{array}{l}
      z_m = \left|z\right|
      \\
      y_m = \left|y\right|
      \\
      x_m = \left|x\right|
      \\
      [x_m, y_m, z_m] = \mathsf{sort}([x_m, y_m, z_m])\\
      \\
      \sqrt{\mathsf{fma}\left(z\_m, z\_m, y\_m \cdot y\_m\right)}
      \end{array}
      
      Derivation
      1. Initial program 48.2%

        \[\sqrt{x \cdot x + \left(y \cdot y + z \cdot z\right)} \]
      2. Add Preprocessing
      3. Taylor expanded in x around 0

        \[\leadsto \sqrt{\color{blue}{{y}^{2} + {z}^{2}}} \]
      4. Step-by-step derivation
        1. +-commutativeN/A

          \[\leadsto \sqrt{\color{blue}{{z}^{2} + {y}^{2}}} \]
        2. unpow2N/A

          \[\leadsto \sqrt{\color{blue}{z \cdot z} + {y}^{2}} \]
        3. lower-fma.f64N/A

          \[\leadsto \sqrt{\color{blue}{\mathsf{fma}\left(z, z, {y}^{2}\right)}} \]
        4. unpow2N/A

          \[\leadsto \sqrt{\mathsf{fma}\left(z, z, \color{blue}{y \cdot y}\right)} \]
        5. lower-*.f6433.5

          \[\leadsto \sqrt{\mathsf{fma}\left(z, z, \color{blue}{y \cdot y}\right)} \]
      5. Applied rewrites33.5%

        \[\leadsto \sqrt{\color{blue}{\mathsf{fma}\left(z, z, y \cdot y\right)}} \]
      6. Add Preprocessing

      Alternative 4: 44.7% accurate, 2.0× speedup?

      \[\begin{array}{l} z_m = \left|z\right| \\ y_m = \left|y\right| \\ x_m = \left|x\right| \\ [x_m, y_m, z_m] = \mathsf{sort}([x_m, y_m, z_m])\\ \\ \sqrt{z\_m \cdot z\_m} \end{array} \]
      z_m = (fabs.f64 z)
      y_m = (fabs.f64 y)
      x_m = (fabs.f64 x)
      NOTE: x_m, y_m, and z_m should be sorted in increasing order before calling this function.
      (FPCore (x_m y_m z_m) :precision binary64 (sqrt (* z_m z_m)))
      z_m = fabs(z);
      y_m = fabs(y);
      x_m = fabs(x);
      assert(x_m < y_m && y_m < z_m);
      double code(double x_m, double y_m, double z_m) {
      	return sqrt((z_m * z_m));
      }
      
      z_m = abs(z)
      y_m = abs(y)
      x_m = abs(x)
      NOTE: x_m, y_m, and z_m should be sorted in increasing order before calling this function.
      real(8) function code(x_m, y_m, z_m)
          real(8), intent (in) :: x_m
          real(8), intent (in) :: y_m
          real(8), intent (in) :: z_m
          code = sqrt((z_m * z_m))
      end function
      
      z_m = Math.abs(z);
      y_m = Math.abs(y);
      x_m = Math.abs(x);
      assert x_m < y_m && y_m < z_m;
      public static double code(double x_m, double y_m, double z_m) {
      	return Math.sqrt((z_m * z_m));
      }
      
      z_m = math.fabs(z)
      y_m = math.fabs(y)
      x_m = math.fabs(x)
      [x_m, y_m, z_m] = sort([x_m, y_m, z_m])
      def code(x_m, y_m, z_m):
      	return math.sqrt((z_m * z_m))
      
      z_m = abs(z)
      y_m = abs(y)
      x_m = abs(x)
      x_m, y_m, z_m = sort([x_m, y_m, z_m])
      function code(x_m, y_m, z_m)
      	return sqrt(Float64(z_m * z_m))
      end
      
      z_m = abs(z);
      y_m = abs(y);
      x_m = abs(x);
      x_m, y_m, z_m = num2cell(sort([x_m, y_m, z_m])){:}
      function tmp = code(x_m, y_m, z_m)
      	tmp = sqrt((z_m * z_m));
      end
      
      z_m = N[Abs[z], $MachinePrecision]
      y_m = N[Abs[y], $MachinePrecision]
      x_m = N[Abs[x], $MachinePrecision]
      NOTE: x_m, y_m, and z_m should be sorted in increasing order before calling this function.
      code[x$95$m_, y$95$m_, z$95$m_] := N[Sqrt[N[(z$95$m * z$95$m), $MachinePrecision]], $MachinePrecision]
      
      \begin{array}{l}
      z_m = \left|z\right|
      \\
      y_m = \left|y\right|
      \\
      x_m = \left|x\right|
      \\
      [x_m, y_m, z_m] = \mathsf{sort}([x_m, y_m, z_m])\\
      \\
      \sqrt{z\_m \cdot z\_m}
      \end{array}
      
      Derivation
      1. Initial program 48.2%

        \[\sqrt{x \cdot x + \left(y \cdot y + z \cdot z\right)} \]
      2. Add Preprocessing
      3. Taylor expanded in x around 0

        \[\leadsto \sqrt{\color{blue}{{y}^{2} + {z}^{2}}} \]
      4. Step-by-step derivation
        1. +-commutativeN/A

          \[\leadsto \sqrt{\color{blue}{{z}^{2} + {y}^{2}}} \]
        2. unpow2N/A

          \[\leadsto \sqrt{\color{blue}{z \cdot z} + {y}^{2}} \]
        3. lower-fma.f64N/A

          \[\leadsto \sqrt{\color{blue}{\mathsf{fma}\left(z, z, {y}^{2}\right)}} \]
        4. unpow2N/A

          \[\leadsto \sqrt{\mathsf{fma}\left(z, z, \color{blue}{y \cdot y}\right)} \]
        5. lower-*.f6433.5

          \[\leadsto \sqrt{\mathsf{fma}\left(z, z, \color{blue}{y \cdot y}\right)} \]
      5. Applied rewrites33.5%

        \[\leadsto \sqrt{\color{blue}{\mathsf{fma}\left(z, z, y \cdot y\right)}} \]
      6. Taylor expanded in y around 0

        \[\leadsto \sqrt{{z}^{\color{blue}{2}}} \]
      7. Step-by-step derivation
        1. Applied rewrites18.5%

          \[\leadsto \sqrt{z \cdot \color{blue}{z}} \]
        2. Add Preprocessing

        Alternative 5: 5.5% accurate, 2.0× speedup?

        \[\begin{array}{l} z_m = \left|z\right| \\ y_m = \left|y\right| \\ x_m = \left|x\right| \\ [x_m, y_m, z_m] = \mathsf{sort}([x_m, y_m, z_m])\\ \\ \sqrt{y\_m \cdot y\_m} \end{array} \]
        z_m = (fabs.f64 z)
        y_m = (fabs.f64 y)
        x_m = (fabs.f64 x)
        NOTE: x_m, y_m, and z_m should be sorted in increasing order before calling this function.
        (FPCore (x_m y_m z_m) :precision binary64 (sqrt (* y_m y_m)))
        z_m = fabs(z);
        y_m = fabs(y);
        x_m = fabs(x);
        assert(x_m < y_m && y_m < z_m);
        double code(double x_m, double y_m, double z_m) {
        	return sqrt((y_m * y_m));
        }
        
        z_m = abs(z)
        y_m = abs(y)
        x_m = abs(x)
        NOTE: x_m, y_m, and z_m should be sorted in increasing order before calling this function.
        real(8) function code(x_m, y_m, z_m)
            real(8), intent (in) :: x_m
            real(8), intent (in) :: y_m
            real(8), intent (in) :: z_m
            code = sqrt((y_m * y_m))
        end function
        
        z_m = Math.abs(z);
        y_m = Math.abs(y);
        x_m = Math.abs(x);
        assert x_m < y_m && y_m < z_m;
        public static double code(double x_m, double y_m, double z_m) {
        	return Math.sqrt((y_m * y_m));
        }
        
        z_m = math.fabs(z)
        y_m = math.fabs(y)
        x_m = math.fabs(x)
        [x_m, y_m, z_m] = sort([x_m, y_m, z_m])
        def code(x_m, y_m, z_m):
        	return math.sqrt((y_m * y_m))
        
        z_m = abs(z)
        y_m = abs(y)
        x_m = abs(x)
        x_m, y_m, z_m = sort([x_m, y_m, z_m])
        function code(x_m, y_m, z_m)
        	return sqrt(Float64(y_m * y_m))
        end
        
        z_m = abs(z);
        y_m = abs(y);
        x_m = abs(x);
        x_m, y_m, z_m = num2cell(sort([x_m, y_m, z_m])){:}
        function tmp = code(x_m, y_m, z_m)
        	tmp = sqrt((y_m * y_m));
        end
        
        z_m = N[Abs[z], $MachinePrecision]
        y_m = N[Abs[y], $MachinePrecision]
        x_m = N[Abs[x], $MachinePrecision]
        NOTE: x_m, y_m, and z_m should be sorted in increasing order before calling this function.
        code[x$95$m_, y$95$m_, z$95$m_] := N[Sqrt[N[(y$95$m * y$95$m), $MachinePrecision]], $MachinePrecision]
        
        \begin{array}{l}
        z_m = \left|z\right|
        \\
        y_m = \left|y\right|
        \\
        x_m = \left|x\right|
        \\
        [x_m, y_m, z_m] = \mathsf{sort}([x_m, y_m, z_m])\\
        \\
        \sqrt{y\_m \cdot y\_m}
        \end{array}
        
        Derivation
        1. Initial program 48.2%

          \[\sqrt{x \cdot x + \left(y \cdot y + z \cdot z\right)} \]
        2. Add Preprocessing
        3. Taylor expanded in z around 0

          \[\leadsto \sqrt{\color{blue}{{x}^{2} + {y}^{2}}} \]
        4. Step-by-step derivation
          1. +-commutativeN/A

            \[\leadsto \sqrt{\color{blue}{{y}^{2} + {x}^{2}}} \]
          2. unpow2N/A

            \[\leadsto \sqrt{\color{blue}{y \cdot y} + {x}^{2}} \]
          3. lower-fma.f64N/A

            \[\leadsto \sqrt{\color{blue}{\mathsf{fma}\left(y, y, {x}^{2}\right)}} \]
          4. unpow2N/A

            \[\leadsto \sqrt{\mathsf{fma}\left(y, y, \color{blue}{x \cdot x}\right)} \]
          5. lower-*.f6434.1

            \[\leadsto \sqrt{\mathsf{fma}\left(y, y, \color{blue}{x \cdot x}\right)} \]
        5. Applied rewrites34.1%

          \[\leadsto \sqrt{\color{blue}{\mathsf{fma}\left(y, y, x \cdot x\right)}} \]
        6. Taylor expanded in x around 0

          \[\leadsto \sqrt{{y}^{\color{blue}{2}}} \]
        7. Step-by-step derivation
          1. Applied rewrites18.8%

            \[\leadsto \sqrt{y \cdot \color{blue}{y}} \]
          2. Add Preprocessing

          Alternative 6: 1.7% accurate, 10.7× speedup?

          \[\begin{array}{l} z_m = \left|z\right| \\ y_m = \left|y\right| \\ x_m = \left|x\right| \\ [x_m, y_m, z_m] = \mathsf{sort}([x_m, y_m, z_m])\\ \\ -x\_m \end{array} \]
          z_m = (fabs.f64 z)
          y_m = (fabs.f64 y)
          x_m = (fabs.f64 x)
          NOTE: x_m, y_m, and z_m should be sorted in increasing order before calling this function.
          (FPCore (x_m y_m z_m) :precision binary64 (- x_m))
          z_m = fabs(z);
          y_m = fabs(y);
          x_m = fabs(x);
          assert(x_m < y_m && y_m < z_m);
          double code(double x_m, double y_m, double z_m) {
          	return -x_m;
          }
          
          z_m = abs(z)
          y_m = abs(y)
          x_m = abs(x)
          NOTE: x_m, y_m, and z_m should be sorted in increasing order before calling this function.
          real(8) function code(x_m, y_m, z_m)
              real(8), intent (in) :: x_m
              real(8), intent (in) :: y_m
              real(8), intent (in) :: z_m
              code = -x_m
          end function
          
          z_m = Math.abs(z);
          y_m = Math.abs(y);
          x_m = Math.abs(x);
          assert x_m < y_m && y_m < z_m;
          public static double code(double x_m, double y_m, double z_m) {
          	return -x_m;
          }
          
          z_m = math.fabs(z)
          y_m = math.fabs(y)
          x_m = math.fabs(x)
          [x_m, y_m, z_m] = sort([x_m, y_m, z_m])
          def code(x_m, y_m, z_m):
          	return -x_m
          
          z_m = abs(z)
          y_m = abs(y)
          x_m = abs(x)
          x_m, y_m, z_m = sort([x_m, y_m, z_m])
          function code(x_m, y_m, z_m)
          	return Float64(-x_m)
          end
          
          z_m = abs(z);
          y_m = abs(y);
          x_m = abs(x);
          x_m, y_m, z_m = num2cell(sort([x_m, y_m, z_m])){:}
          function tmp = code(x_m, y_m, z_m)
          	tmp = -x_m;
          end
          
          z_m = N[Abs[z], $MachinePrecision]
          y_m = N[Abs[y], $MachinePrecision]
          x_m = N[Abs[x], $MachinePrecision]
          NOTE: x_m, y_m, and z_m should be sorted in increasing order before calling this function.
          code[x$95$m_, y$95$m_, z$95$m_] := (-x$95$m)
          
          \begin{array}{l}
          z_m = \left|z\right|
          \\
          y_m = \left|y\right|
          \\
          x_m = \left|x\right|
          \\
          [x_m, y_m, z_m] = \mathsf{sort}([x_m, y_m, z_m])\\
          \\
          -x\_m
          \end{array}
          
          Derivation
          1. Initial program 48.2%

            \[\sqrt{x \cdot x + \left(y \cdot y + z \cdot z\right)} \]
          2. Add Preprocessing
          3. Taylor expanded in x around -inf

            \[\leadsto \color{blue}{-1 \cdot x} \]
          4. Step-by-step derivation
            1. mul-1-negN/A

              \[\leadsto \color{blue}{\mathsf{neg}\left(x\right)} \]
            2. lower-neg.f6423.0

              \[\leadsto \color{blue}{-x} \]
          5. Applied rewrites23.0%

            \[\leadsto \color{blue}{-x} \]
          6. Add Preprocessing

          Developer Target 1: 100.0% accurate, 0.2× speedup?

          \[\begin{array}{l} \\ \mathsf{hypot}\left(x, \mathsf{hypot}\left(y, z\right)\right) \end{array} \]
          (FPCore (x y z) :precision binary64 (hypot x (hypot y z)))
          double code(double x, double y, double z) {
          	return hypot(x, hypot(y, z));
          }
          
          public static double code(double x, double y, double z) {
          	return Math.hypot(x, Math.hypot(y, z));
          }
          
          def code(x, y, z):
          	return math.hypot(x, math.hypot(y, z))
          
          function code(x, y, z)
          	return hypot(x, hypot(y, z))
          end
          
          function tmp = code(x, y, z)
          	tmp = hypot(x, hypot(y, z));
          end
          
          code[x_, y_, z_] := N[Sqrt[x ^ 2 + N[Sqrt[y ^ 2 + z ^ 2], $MachinePrecision] ^ 2], $MachinePrecision]
          
          \begin{array}{l}
          
          \\
          \mathsf{hypot}\left(x, \mathsf{hypot}\left(y, z\right)\right)
          \end{array}
          

          Reproduce

          ?
          herbie shell --seed 2024332 
          (FPCore (x y z)
            :name "bug366 (missed optimization)"
            :precision binary64
          
            :alt
            (! :herbie-platform default (hypot x (hypot y z)))
          
            (sqrt (+ (* x x) (+ (* y y) (* z z)))))