bug366 (missed optimization)

Percentage Accurate: 44.5% → 100.0%
Time: 3.9s
Alternatives: 6
Speedup: 1.5×

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))));
}
module fmin_fmax_functions
    implicit none
    private
    public fmax
    public fmin

    interface fmax
        module procedure fmax88
        module procedure fmax44
        module procedure fmax84
        module procedure fmax48
    end interface
    interface fmin
        module procedure fmin88
        module procedure fmin44
        module procedure fmin84
        module procedure fmin48
    end interface
contains
    real(8) function fmax88(x, y) result (res)
        real(8), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(x, max(x, y), y /= y), x /= x)
    end function
    real(4) function fmax44(x, y) result (res)
        real(4), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(y, merge(x, max(x, y), y /= y), x /= x)
    end function
    real(8) function fmax84(x, y) result(res)
        real(8), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(dble(y), merge(x, max(x, dble(y)), y /= y), x /= x)
    end function
    real(8) function fmax48(x, y) result(res)
        real(4), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(dble(x), max(dble(x), y), y /= y), x /= x)
    end function
    real(8) function fmin88(x, y) result (res)
        real(8), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(x, min(x, y), y /= y), x /= x)
    end function
    real(4) function fmin44(x, y) result (res)
        real(4), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(y, merge(x, min(x, y), y /= y), x /= x)
    end function
    real(8) function fmin84(x, y) result(res)
        real(8), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(dble(y), merge(x, min(x, dble(y)), y /= y), x /= x)
    end function
    real(8) function fmin48(x, y) result(res)
        real(4), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(dble(x), min(dble(x), y), y /= y), x /= x)
    end function
end module

real(8) function code(x, y, z)
use fmin_fmax_functions
    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: 44.5% 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))));
}
module fmin_fmax_functions
    implicit none
    private
    public fmax
    public fmin

    interface fmax
        module procedure fmax88
        module procedure fmax44
        module procedure fmax84
        module procedure fmax48
    end interface
    interface fmin
        module procedure fmin88
        module procedure fmin44
        module procedure fmin84
        module procedure fmin48
    end interface
contains
    real(8) function fmax88(x, y) result (res)
        real(8), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(x, max(x, y), y /= y), x /= x)
    end function
    real(4) function fmax44(x, y) result (res)
        real(4), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(y, merge(x, max(x, y), y /= y), x /= x)
    end function
    real(8) function fmax84(x, y) result(res)
        real(8), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(dble(y), merge(x, max(x, dble(y)), y /= y), x /= x)
    end function
    real(8) function fmax48(x, y) result(res)
        real(4), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(dble(x), max(dble(x), y), y /= y), x /= x)
    end function
    real(8) function fmin88(x, y) result (res)
        real(8), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(x, min(x, y), y /= y), x /= x)
    end function
    real(4) function fmin44(x, y) result (res)
        real(4), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(y, merge(x, min(x, y), y /= y), x /= x)
    end function
    real(8) function fmin84(x, y) result(res)
        real(8), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(dble(y), merge(x, min(x, dble(y)), y /= y), x /= x)
    end function
    real(8) function fmin48(x, y) result(res)
        real(4), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(dble(x), min(dble(x), y), y /= y), x /= x)
    end function
end module

real(8) function code(x, y, z)
use fmin_fmax_functions
    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 45.0%

    \[\sqrt{x \cdot x + \left(y \cdot y + z \cdot z\right)} \]
  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

      \[\leadsto \sqrt{{z}^{2} + \color{blue}{y \cdot y}} \]
    3. fp-cancel-sign-sub-invN/A

      \[\leadsto \sqrt{\color{blue}{{z}^{2} - \left(\mathsf{neg}\left(y\right)\right) \cdot y}} \]
    4. mul-1-negN/A

      \[\leadsto \sqrt{{z}^{2} - \color{blue}{\left(-1 \cdot y\right)} \cdot y} \]
    5. fp-cancel-sub-sign-invN/A

      \[\leadsto \sqrt{\color{blue}{{z}^{2} + \left(\mathsf{neg}\left(-1 \cdot y\right)\right) \cdot y}} \]
    6. unpow2N/A

      \[\leadsto \sqrt{\color{blue}{z \cdot z} + \left(\mathsf{neg}\left(-1 \cdot y\right)\right) \cdot y} \]
    7. distribute-lft-neg-inN/A

      \[\leadsto \sqrt{z \cdot z + \color{blue}{\left(\mathsf{neg}\left(\left(-1 \cdot y\right) \cdot y\right)\right)}} \]
    8. distribute-rgt-neg-inN/A

      \[\leadsto \sqrt{z \cdot z + \color{blue}{\left(-1 \cdot y\right) \cdot \left(\mathsf{neg}\left(y\right)\right)}} \]
    9. mul-1-negN/A

      \[\leadsto \sqrt{z \cdot z + \color{blue}{\left(\mathsf{neg}\left(y\right)\right)} \cdot \left(\mathsf{neg}\left(y\right)\right)} \]
    10. sqr-neg-revN/A

      \[\leadsto \sqrt{z \cdot z + \color{blue}{y \cdot y}} \]
    11. lower-hypot.f6462.9

      \[\leadsto \color{blue}{\mathsf{hypot}\left(z, y\right)} \]
  5. Applied rewrites62.9%

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

Alternative 2: 99.2% accurate, 1.4× speedup?

\[\begin{array}{l} z_m = \left|z\right| \\ y_m = \left|y\right| \\ x_m = \left|x\right| \\ [x_m, y_m, z_m] = \mathsf{sort}([x_m, y_m, z_m])\\ \\ \mathsf{fma}\left(\frac{0.5}{z\_m} \cdot y\_m, y\_m, z\_m\right) \end{array} \]
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 (* (/ 0.5 z_m) y_m) y_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 fma(((0.5 / z_m) * y_m), y_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 fma(Float64(Float64(0.5 / z_m) * y_m), y_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[(N[(N[(0.5 / z$95$m), $MachinePrecision] * y$95$m), $MachinePrecision] * y$95$m + 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{0.5}{z\_m} \cdot y\_m, y\_m, z\_m\right)
\end{array}
Derivation
  1. Initial program 45.0%

    \[\sqrt{x \cdot x + \left(y \cdot y + z \cdot z\right)} \]
  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

      \[\leadsto \sqrt{{z}^{2} + \color{blue}{y \cdot y}} \]
    3. fp-cancel-sign-sub-invN/A

      \[\leadsto \sqrt{\color{blue}{{z}^{2} - \left(\mathsf{neg}\left(y\right)\right) \cdot y}} \]
    4. mul-1-negN/A

      \[\leadsto \sqrt{{z}^{2} - \color{blue}{\left(-1 \cdot y\right)} \cdot y} \]
    5. fp-cancel-sub-sign-invN/A

      \[\leadsto \sqrt{\color{blue}{{z}^{2} + \left(\mathsf{neg}\left(-1 \cdot y\right)\right) \cdot y}} \]
    6. unpow2N/A

      \[\leadsto \sqrt{\color{blue}{z \cdot z} + \left(\mathsf{neg}\left(-1 \cdot y\right)\right) \cdot y} \]
    7. distribute-lft-neg-inN/A

      \[\leadsto \sqrt{z \cdot z + \color{blue}{\left(\mathsf{neg}\left(\left(-1 \cdot y\right) \cdot y\right)\right)}} \]
    8. distribute-rgt-neg-inN/A

      \[\leadsto \sqrt{z \cdot z + \color{blue}{\left(-1 \cdot y\right) \cdot \left(\mathsf{neg}\left(y\right)\right)}} \]
    9. mul-1-negN/A

      \[\leadsto \sqrt{z \cdot z + \color{blue}{\left(\mathsf{neg}\left(y\right)\right)} \cdot \left(\mathsf{neg}\left(y\right)\right)} \]
    10. sqr-neg-revN/A

      \[\leadsto \sqrt{z \cdot z + \color{blue}{y \cdot y}} \]
    11. lower-hypot.f6462.9

      \[\leadsto \color{blue}{\mathsf{hypot}\left(z, y\right)} \]
  5. Applied rewrites62.9%

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

    \[\leadsto z + \color{blue}{\frac{1}{2} \cdot \frac{{y}^{2}}{z}} \]
  7. Step-by-step derivation
    1. Applied rewrites19.7%

      \[\leadsto \mathsf{fma}\left(\frac{0.5}{z}, \color{blue}{y \cdot y}, z\right) \]
    2. Step-by-step derivation
      1. Applied rewrites21.9%

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

      Alternative 3: 44.5% 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 45.0%

        \[\sqrt{x \cdot x + \left(y \cdot y + z \cdot z\right)} \]
      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

          \[\leadsto \sqrt{{z}^{2} + \color{blue}{y \cdot y}} \]
        3. fp-cancel-sign-sub-invN/A

          \[\leadsto \sqrt{\color{blue}{{z}^{2} - \left(\mathsf{neg}\left(y\right)\right) \cdot y}} \]
        4. mul-1-negN/A

          \[\leadsto \sqrt{{z}^{2} - \color{blue}{\left(-1 \cdot y\right)} \cdot y} \]
        5. fp-cancel-sub-sign-invN/A

          \[\leadsto \sqrt{\color{blue}{{z}^{2} + \left(\mathsf{neg}\left(-1 \cdot y\right)\right) \cdot y}} \]
        6. unpow2N/A

          \[\leadsto \sqrt{\color{blue}{z \cdot z} + \left(\mathsf{neg}\left(-1 \cdot y\right)\right) \cdot y} \]
        7. distribute-lft-neg-inN/A

          \[\leadsto \sqrt{z \cdot z + \color{blue}{\left(\mathsf{neg}\left(\left(-1 \cdot y\right) \cdot y\right)\right)}} \]
        8. distribute-rgt-neg-inN/A

          \[\leadsto \sqrt{z \cdot z + \color{blue}{\left(-1 \cdot y\right) \cdot \left(\mathsf{neg}\left(y\right)\right)}} \]
        9. mul-1-negN/A

          \[\leadsto \sqrt{z \cdot z + \color{blue}{\left(\mathsf{neg}\left(y\right)\right)} \cdot \left(\mathsf{neg}\left(y\right)\right)} \]
        10. sqr-neg-revN/A

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

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

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

          \[\leadsto \sqrt{\mathsf{fma}\left(z, z, \color{blue}{y \cdot y}\right)} \]
        14. lower-*.f6431.1

          \[\leadsto \sqrt{\mathsf{fma}\left(z, z, \color{blue}{y \cdot y}\right)} \]
      5. Applied rewrites31.1%

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

      Alternative 4: 5.5% accurate, 1.5× speedup?

      \[\begin{array}{l} z_m = \left|z\right| \\ y_m = \left|y\right| \\ x_m = \left|x\right| \\ [x_m, y_m, z_m] = \mathsf{sort}([x_m, y_m, z_m])\\ \\ \sqrt{\mathsf{fma}\left(y\_m, y\_m, x\_m \cdot x\_m\right)} \end{array} \]
      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 y_m y_m (* x_m 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 sqrt(fma(y_m, y_m, (x_m * 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 sqrt(fma(y_m, y_m, Float64(x_m * 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_] := N[Sqrt[N[(y$95$m * y$95$m + N[(x$95$m * x$95$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(y\_m, y\_m, x\_m \cdot x\_m\right)}
      \end{array}
      
      Derivation
      1. Initial program 45.0%

        \[\sqrt{x \cdot x + \left(y \cdot y + z \cdot z\right)} \]
      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

          \[\leadsto \sqrt{{y}^{2} + \color{blue}{x \cdot x}} \]
        3. fp-cancel-sign-sub-invN/A

          \[\leadsto \sqrt{\color{blue}{{y}^{2} - \left(\mathsf{neg}\left(x\right)\right) \cdot x}} \]
        4. mul-1-negN/A

          \[\leadsto \sqrt{{y}^{2} - \color{blue}{\left(-1 \cdot x\right)} \cdot x} \]
        5. fp-cancel-sub-sign-invN/A

          \[\leadsto \sqrt{\color{blue}{{y}^{2} + \left(\mathsf{neg}\left(-1 \cdot x\right)\right) \cdot x}} \]
        6. unpow2N/A

          \[\leadsto \sqrt{\color{blue}{y \cdot y} + \left(\mathsf{neg}\left(-1 \cdot x\right)\right) \cdot x} \]
        7. distribute-lft-neg-inN/A

          \[\leadsto \sqrt{y \cdot y + \color{blue}{\left(\mathsf{neg}\left(\left(-1 \cdot x\right) \cdot x\right)\right)}} \]
        8. mul-1-negN/A

          \[\leadsto \sqrt{y \cdot y + \left(\mathsf{neg}\left(\color{blue}{\left(\mathsf{neg}\left(x\right)\right)} \cdot x\right)\right)} \]
        9. distribute-lft-neg-inN/A

          \[\leadsto \sqrt{y \cdot y + \left(\mathsf{neg}\left(\color{blue}{\left(\mathsf{neg}\left(x \cdot x\right)\right)}\right)\right)} \]
        10. unpow2N/A

          \[\leadsto \sqrt{y \cdot y + \left(\mathsf{neg}\left(\left(\mathsf{neg}\left(\color{blue}{{x}^{2}}\right)\right)\right)\right)} \]
        11. remove-double-negN/A

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

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

          \[\leadsto \sqrt{\mathsf{fma}\left(y, y, \color{blue}{x \cdot x}\right)} \]
        14. lower-*.f6429.7

          \[\leadsto \sqrt{\mathsf{fma}\left(y, y, \color{blue}{x \cdot x}\right)} \]
      5. Applied rewrites29.7%

        \[\leadsto \sqrt{\color{blue}{\mathsf{fma}\left(y, y, x \cdot x\right)}} \]
      6. 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 =     private
      y_m =     private
      x_m =     private
      NOTE: x_m, y_m, and z_m should be sorted in increasing order before calling this function.
      module fmin_fmax_functions
          implicit none
          private
          public fmax
          public fmin
      
          interface fmax
              module procedure fmax88
              module procedure fmax44
              module procedure fmax84
              module procedure fmax48
          end interface
          interface fmin
              module procedure fmin88
              module procedure fmin44
              module procedure fmin84
              module procedure fmin48
          end interface
      contains
          real(8) function fmax88(x, y) result (res)
              real(8), intent (in) :: x
              real(8), intent (in) :: y
              res = merge(y, merge(x, max(x, y), y /= y), x /= x)
          end function
          real(4) function fmax44(x, y) result (res)
              real(4), intent (in) :: x
              real(4), intent (in) :: y
              res = merge(y, merge(x, max(x, y), y /= y), x /= x)
          end function
          real(8) function fmax84(x, y) result(res)
              real(8), intent (in) :: x
              real(4), intent (in) :: y
              res = merge(dble(y), merge(x, max(x, dble(y)), y /= y), x /= x)
          end function
          real(8) function fmax48(x, y) result(res)
              real(4), intent (in) :: x
              real(8), intent (in) :: y
              res = merge(y, merge(dble(x), max(dble(x), y), y /= y), x /= x)
          end function
          real(8) function fmin88(x, y) result (res)
              real(8), intent (in) :: x
              real(8), intent (in) :: y
              res = merge(y, merge(x, min(x, y), y /= y), x /= x)
          end function
          real(4) function fmin44(x, y) result (res)
              real(4), intent (in) :: x
              real(4), intent (in) :: y
              res = merge(y, merge(x, min(x, y), y /= y), x /= x)
          end function
          real(8) function fmin84(x, y) result(res)
              real(8), intent (in) :: x
              real(4), intent (in) :: y
              res = merge(dble(y), merge(x, min(x, dble(y)), y /= y), x /= x)
          end function
          real(8) function fmin48(x, y) result(res)
              real(4), intent (in) :: x
              real(8), intent (in) :: y
              res = merge(y, merge(dble(x), min(dble(x), y), y /= y), x /= x)
          end function
      end module
      
      real(8) function code(x_m, y_m, z_m)
      use fmin_fmax_functions
          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 45.0%

        \[\sqrt{x \cdot x + \left(y \cdot y + z \cdot z\right)} \]
      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

          \[\leadsto \sqrt{{y}^{2} + \color{blue}{x \cdot x}} \]
        3. fp-cancel-sign-sub-invN/A

          \[\leadsto \sqrt{\color{blue}{{y}^{2} - \left(\mathsf{neg}\left(x\right)\right) \cdot x}} \]
        4. mul-1-negN/A

          \[\leadsto \sqrt{{y}^{2} - \color{blue}{\left(-1 \cdot x\right)} \cdot x} \]
        5. fp-cancel-sub-sign-invN/A

          \[\leadsto \sqrt{\color{blue}{{y}^{2} + \left(\mathsf{neg}\left(-1 \cdot x\right)\right) \cdot x}} \]
        6. unpow2N/A

          \[\leadsto \sqrt{\color{blue}{y \cdot y} + \left(\mathsf{neg}\left(-1 \cdot x\right)\right) \cdot x} \]
        7. distribute-lft-neg-inN/A

          \[\leadsto \sqrt{y \cdot y + \color{blue}{\left(\mathsf{neg}\left(\left(-1 \cdot x\right) \cdot x\right)\right)}} \]
        8. mul-1-negN/A

          \[\leadsto \sqrt{y \cdot y + \left(\mathsf{neg}\left(\color{blue}{\left(\mathsf{neg}\left(x\right)\right)} \cdot x\right)\right)} \]
        9. distribute-lft-neg-inN/A

          \[\leadsto \sqrt{y \cdot y + \left(\mathsf{neg}\left(\color{blue}{\left(\mathsf{neg}\left(x \cdot x\right)\right)}\right)\right)} \]
        10. unpow2N/A

          \[\leadsto \sqrt{y \cdot y + \left(\mathsf{neg}\left(\left(\mathsf{neg}\left(\color{blue}{{x}^{2}}\right)\right)\right)\right)} \]
        11. remove-double-negN/A

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

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

          \[\leadsto \sqrt{\mathsf{fma}\left(y, y, \color{blue}{x \cdot x}\right)} \]
        14. lower-*.f6429.7

          \[\leadsto \sqrt{\mathsf{fma}\left(y, y, \color{blue}{x \cdot x}\right)} \]
      5. Applied rewrites29.7%

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

        \[\leadsto \sqrt{{y}^{\color{blue}{2}}} \]
      7. Step-by-step derivation
        1. Applied rewrites15.6%

          \[\leadsto \sqrt{y \cdot \color{blue}{y}} \]
        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 =     private
        y_m =     private
        x_m =     private
        NOTE: x_m, y_m, and z_m should be sorted in increasing order before calling this function.
        module fmin_fmax_functions
            implicit none
            private
            public fmax
            public fmin
        
            interface fmax
                module procedure fmax88
                module procedure fmax44
                module procedure fmax84
                module procedure fmax48
            end interface
            interface fmin
                module procedure fmin88
                module procedure fmin44
                module procedure fmin84
                module procedure fmin48
            end interface
        contains
            real(8) function fmax88(x, y) result (res)
                real(8), intent (in) :: x
                real(8), intent (in) :: y
                res = merge(y, merge(x, max(x, y), y /= y), x /= x)
            end function
            real(4) function fmax44(x, y) result (res)
                real(4), intent (in) :: x
                real(4), intent (in) :: y
                res = merge(y, merge(x, max(x, y), y /= y), x /= x)
            end function
            real(8) function fmax84(x, y) result(res)
                real(8), intent (in) :: x
                real(4), intent (in) :: y
                res = merge(dble(y), merge(x, max(x, dble(y)), y /= y), x /= x)
            end function
            real(8) function fmax48(x, y) result(res)
                real(4), intent (in) :: x
                real(8), intent (in) :: y
                res = merge(y, merge(dble(x), max(dble(x), y), y /= y), x /= x)
            end function
            real(8) function fmin88(x, y) result (res)
                real(8), intent (in) :: x
                real(8), intent (in) :: y
                res = merge(y, merge(x, min(x, y), y /= y), x /= x)
            end function
            real(4) function fmin44(x, y) result (res)
                real(4), intent (in) :: x
                real(4), intent (in) :: y
                res = merge(y, merge(x, min(x, y), y /= y), x /= x)
            end function
            real(8) function fmin84(x, y) result(res)
                real(8), intent (in) :: x
                real(4), intent (in) :: y
                res = merge(dble(y), merge(x, min(x, dble(y)), y /= y), x /= x)
            end function
            real(8) function fmin48(x, y) result(res)
                real(4), intent (in) :: x
                real(8), intent (in) :: y
                res = merge(y, merge(dble(x), min(dble(x), y), y /= y), x /= x)
            end function
        end module
        
        real(8) function code(x_m, y_m, z_m)
        use fmin_fmax_functions
            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 45.0%

          \[\sqrt{x \cdot x + \left(y \cdot y + z \cdot z\right)} \]
        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.f6421.9

            \[\leadsto \color{blue}{-x} \]
        5. Applied rewrites21.9%

          \[\leadsto \color{blue}{-x} \]
        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 2025015 
        (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)))))