double Tween_QuinticInOutEasing(double k) {
  k *= 2;
  if (k < 1) {
    return 0.5 * k * k * k * k * k;
  }
  k -= 2;
  return 0.5 * (k * k * k * k * k + 2);
}


x86 assembly (clang, -O0):
<Tween_QuinticInOutEasing>:
push   %rbp
mov    %rsp,%rbp
movsd  %xmm0,-0x10(%rbp)
movsd  0xef7(%rip),%xmm0
mulsd  -0x10(%rbp),%xmm0
movsd  %xmm0,-0x10(%rbp)
movsd  0xedd(%rip),%xmm0
ucomisd -0x10(%rbp),%xmm0
jbe    1159 <Tween_QuinticInOutEasing+0x59>
movsd  0xeda(%rip),%xmm0
mulsd  -0x10(%rbp),%xmm0
mulsd  -0x10(%rbp),%xmm0
mulsd  -0x10(%rbp),%xmm0
mulsd  -0x10(%rbp),%xmm0
mulsd  -0x10(%rbp),%xmm0
movsd  %xmm0,-0x8(%rbp)
jmp    11a9 <Tween_QuinticInOutEasing+0xa9>
movsd  -0x10(%rbp),%xmm0
movsd  0xea2(%rip),%xmm1
subsd  %xmm1,%xmm0
movsd  %xmm0,-0x10(%rbp)
movsd  -0x10(%rbp),%xmm1
mulsd  -0x10(%rbp),%xmm1
mulsd  -0x10(%rbp),%xmm1
mulsd  -0x10(%rbp),%xmm1
movsd  -0x10(%rbp),%xmm0
mulsd  %xmm0,%xmm1
movsd  0xe74(%rip),%xmm0
addsd  %xmm0,%xmm1
movsd  0xe70(%rip),%xmm0
mulsd  %xmm1,%xmm0
movsd  %xmm0,-0x8(%rbp)
movsd  -0x8(%rbp),%xmm0
pop    %rbp
ret

x86 assembly (clang, -O2):
<Tween_QuinticInOutEasing>:
addsd  %xmm0,%xmm0
movsd  0xef4(%rip),%xmm1
ucomisd %xmm0,%xmm1
jbe    1133 <Tween_QuinticInOutEasing+0x33>
movsd  0xefe(%rip),%xmm1
mulsd  %xmm0,%xmm1
mulsd  %xmm0,%xmm1
mulsd  %xmm0,%xmm1
mulsd  %xmm0,%xmm1
mulsd  %xmm0,%xmm1
movapd %xmm1,%xmm0
ret
addsd  0xecd(%rip),%xmm0
movapd %xmm0,%xmm1
mulsd  %xmm0,%xmm1
mulsd  %xmm0,%xmm1
mulsd  %xmm0,%xmm1
mulsd  %xmm0,%xmm1
addsd  0xeb9(%rip),%xmm1
mulsd  0xeb9(%rip),%xmm1
movapd %xmm1,%xmm0
ret

LLVM IR (-O0):
define double @Tween_QuinticInOutEasing(double %0) {
%2 = alloca double
%3 = alloca double
store double %0, double* %3
%4 = load double, double* %3
%5 = fmul double %4, 2.000000e+00
store double %5, double* %3
%6 = load double, double* %3
%7 = fcmp olt double %6, 1.000000e+00
br i1 %7, label %8, label %19
8: ; preds = %1
%9 = load double, double* %3
%10 = fmul double 5.000000e-01, %9
%11 = load double, double* %3
%12 = fmul double %10, %11
%13 = load double, double* %3
%14 = fmul double %12, %13
%15 = load double, double* %3
%16 = fmul double %14, %15
%17 = load double, double* %3
%18 = fmul double %16, %17
store double %18, double* %2
br label %32
19: ; preds = %1
%20 = load double, double* %3
%21 = fsub double %20, 2.000000e+00
store double %21, double* %3
%22 = load double, double* %3
%23 = load double, double* %3
%24 = fmul double %22, %23
%25 = load double, double* %3
%26 = fmul double %24, %25
%27 = load double, double* %3
%28 = fmul double %26, %27
%29 = load double, double* %3
%30 = call double @llvm.fmuladd.f64(double %28, double %29, double 2.000000e+00)
%31 = fmul double 5.000000e-01, %30
store double %31, double* %2
br label %32
32: ; preds = %19, %8
%33 = load double, double* %2
ret double %33
}

LLVM IR (-O2):
define double @Tween_QuinticInOutEasing(double %0) {
%2 = fmul double %0, 2.000000e+00
%3 = fcmp olt double %2, 1.000000e+00
br i1 %3, label %4, label %10
4: ; preds = %1
%5 = fmul double %2, 5.000000e-01
%6 = fmul double %2, %5
%7 = fmul double %2, %6
%8 = fmul double %2, %7
%9 = fmul double %2, %8
br label %17
10: ; preds = %1
%11 = fadd double %2, -2.000000e+00
%12 = fmul double %11, %11
%13 = fmul double %11, %12
%14 = fmul double %11, %13
%15 = tail call double @llvm.fmuladd.f64(double %14, double %11, double 2.000000e+00)
%16 = fmul double %15, 5.000000e-01
br label %17
17: ; preds = %10, %4
%18 = phi double [ %9, %4 ], [ %16, %10 ]
ret double %18
}