bug366 (missed optimization)

Percentage Accurate: 44.2% → 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))));
}
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: 44.2% 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 45.9%

    \[\sqrt{x \cdot x + \left(y \cdot y + z \cdot z\right)} \]
  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.f6468.0

      \[\leadsto \color{blue}{\mathsf{hypot}\left(z, y\right)} \]
  5. Applied rewrites68.0%

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

Alternative 2: 98.4% accurate, 1.4× speedup?

\[\begin{array}{l} z_m = \left|z\right| \\ y_m = \left|y\right| \\ x_m = \left|x\right| \\ [x_m, y_m, z_m] = \mathsf{sort}([x_m, y_m, z_m])\\ \\ \mathsf{fma}\left(\frac{0.5}{z\_m} \cdot x\_m, x\_m, z\_m\right) \end{array} \]
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) x_m) x_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) * x_m), x_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) * x_m), x_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] * x$95$m), $MachinePrecision] * x$95$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 x\_m, x\_m, z\_m\right)
\end{array}
Derivation
  1. Initial program 45.9%

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

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

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

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

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

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

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

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

      \[\leadsto \color{blue}{\mathsf{fma}\left(\frac{z}{z}, \frac{\frac{1}{2} \cdot \left({x}^{2} + {y}^{2}\right)}{z}, z\right)} \]
  5. Applied rewrites19.1%

    \[\leadsto \color{blue}{\mathsf{fma}\left(\frac{z}{z}, \frac{\mathsf{fma}\left(y, y, x \cdot x\right)}{z} \cdot 0.5, z\right)} \]
  6. Taylor expanded in y around 0

    \[\leadsto z + \color{blue}{\frac{1}{2} \cdot \frac{{x}^{2}}{z}} \]
  7. Step-by-step derivation
    1. Applied rewrites19.6%

      \[\leadsto \mathsf{fma}\left(\frac{0.5}{z}, \color{blue}{x \cdot x}, z\right) \]
    2. Step-by-step derivation
      1. Applied rewrites20.1%

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

      Alternative 3: 44.2% 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 45.9%

        \[\sqrt{x \cdot x + \left(y \cdot y + z \cdot z\right)} \]
      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-*.f6432.7

          \[\leadsto \sqrt{\mathsf{fma}\left(z, z, \color{blue}{y \cdot y}\right)} \]
      5. Applied rewrites32.7%

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

      Alternative 4: 43.4% 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 =     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((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 45.9%

        \[\sqrt{x \cdot x + \left(y \cdot y + z \cdot z\right)} \]
      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-*.f6432.7

          \[\leadsto \sqrt{\mathsf{fma}\left(z, z, \color{blue}{y \cdot y}\right)} \]
      5. Applied rewrites32.7%

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

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

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

        Alternative 5: 5.6% 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 45.9%

          \[\sqrt{x \cdot x + \left(y \cdot y + z \cdot z\right)} \]
        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-*.f6432.0

            \[\leadsto \sqrt{\mathsf{fma}\left(y, y, \color{blue}{x \cdot x}\right)} \]
        5. Applied rewrites32.0%

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

          \[\leadsto \sqrt{{y}^{\color{blue}{2}}} \]
        7. Step-by-step derivation
          1. Applied rewrites18.3%

            \[\leadsto \sqrt{y \cdot \color{blue}{y}} \]
          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 45.9%

            \[\sqrt{x \cdot x + \left(y \cdot y + z \cdot z\right)} \]
          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.f6417.3

              \[\leadsto \color{blue}{-x} \]
          5. Applied rewrites17.3%

            \[\leadsto \color{blue}{-x} \]
          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 2025006 
          (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)))))