\[x = 10864 \land y = 18817\]
\[9 \cdot {x}^{4} - \left(y \cdot y\right) \cdot \left(y \cdot y - 2\right) \]
(FPCore (x y)
 :precision binary64
 (- (* 9.0 (pow x 4.0)) (* (* y y) (- (* y y) 2.0))))
double code(double x, double y) {
	return (9.0 * pow(x, 4.0)) - ((y * y) * ((y * y) - 2.0));
}
real(8) function code(x, y)
    real(8), intent (in) :: x
    real(8), intent (in) :: y
    code = (9.0d0 * (x ** 4.0d0)) - ((y * y) * ((y * y) - 2.0d0))
end function
public static double code(double x, double y) {
	return (9.0 * Math.pow(x, 4.0)) - ((y * y) * ((y * y) - 2.0));
}
def code(x, y):
	return (9.0 * math.pow(x, 4.0)) - ((y * y) * ((y * y) - 2.0))
function code(x, y)
	return Float64(Float64(9.0 * (x ^ 4.0)) - Float64(Float64(y * y) * Float64(Float64(y * y) - 2.0)))
end
function tmp = code(x, y)
	tmp = (9.0 * (x ^ 4.0)) - ((y * y) * ((y * y) - 2.0));
end
code[x_, y_] := N[(N[(9.0 * N[Power[x, 4.0], $MachinePrecision]), $MachinePrecision] - N[(N[(y * y), $MachinePrecision] * N[(N[(y * y), $MachinePrecision] - 2.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
9 \cdot {x}^{4} - \left(y \cdot y\right) \cdot \left(y \cdot y - 2\right)

Reproduce

Please include this information when filing a bug report:

herbie shell --seed 2022203 
(FPCore (x y)
  :name "From Rump in a 1983 paper, rewritten"
  :precision binary64
  :pre (and (== x 10864.0) (== y 18817.0))
  (- (* 9.0 (pow x 4.0)) (* (* y y) (- (* y y) 2.0))))

Backtrace

hash-ref: no value found for key key: #<alt (λ (x y) (-.f64 (*.f64 9 (pow.f64 x 4)) (*.f64 (*.f64 y y) (-.f64 (*.f64 y y) 2))))>LC
remove-chnged-pnts/data/pavpan/nightlies/herbie/oopsla21/src/core/alt-table.rkt1270
atab-add-altn/data/pavpan/nightlies/herbie/oopsla21/src/core/alt-table.rkt2660
atab-add-altns/data/pavpan/nightlies/herbie/oopsla21/src/core/alt-table.rkt2420
(unnamed)/usr/share/racket/collects/racket/contract/private/arrow-val-first.rkt48618
finalize-iter!/data/pavpan/nightlies/herbie/oopsla21/src/mainloop.rkt1830
mutate!/data/pavpan/nightlies/herbie/oopsla21/src/mainloop.rkt3480
run-improve!/data/pavpan/nightlies/herbie/oopsla21/src/mainloop.rkt2960
(unnamed)/data/pavpan/nightlies/herbie/oopsla21/src/sandbox.rkt556
(unnamed)/usr/share/racket/pkgs/profile-lib/main.rkt4010
profile-thunk/usr/share/racket/pkgs/profile-lib/main.rkt90
(unnamed)/usr/share/racket/collects/racket/engine.rkt4224