double AURAE_sqrtd(double number) {
  long i;
  double x2, y;
  float y2;
  const double threehalfs = 1.5;
  x2 = number * 0.5;
  y2 = number;
  i = *(long *)&y2;
  i = 0x5f375a86 - ((i) >> 1);
  i = i & 0x7FFFFFFF;
  y2 = *(float *)&i;
  y = y2;
  y = y * (threehalfs - (x2 * y * y));
  y = y * (threehalfs - (x2 * y * y));
  y = y * (threehalfs - (x2 * y * y));
  y = 1.0 / y;
  return y;
}


x86 assembly (clang, -O0):
<AURAE_sqrtd>:
push   %rbp
mov    %rsp,%rbp
movsd  %xmm0,-0x8(%rbp)
movsd  0xef7(%rip),%xmm0
movsd  %xmm0,-0x30(%rbp)
movsd  0xef2(%rip),%xmm0
mulsd  -0x8(%rbp),%xmm0
movsd  %xmm0,-0x18(%rbp)
movsd  -0x8(%rbp),%xmm0
cvtsd2ss %xmm0,%xmm0
movss  %xmm0,-0x24(%rbp)
mov    -0x24(%rbp),%rax
mov    %rax,-0x10(%rbp)
mov    -0x10(%rbp),%rcx
sar    $0x1,%rcx
mov    $0x5f375a86,%eax
sub    %rcx,%rax
mov    %rax,-0x10(%rbp)
mov    -0x10(%rbp),%rax
and    $0x7fffffff,%rax
mov    %rax,-0x10(%rbp)
movss  -0x10(%rbp),%xmm0
movss  %xmm0,-0x24(%rbp)
movss  -0x24(%rbp),%xmm0
cvtss2sd %xmm0,%xmm0
movsd  %xmm0,-0x20(%rbp)
movsd  -0x20(%rbp),%xmm0
movsd  -0x18(%rbp),%xmm1
mulsd  -0x20(%rbp),%xmm1
movsd  -0x20(%rbp),%xmm2
movq   %xmm1,%rax
movabs $0x8000000000000000,%rcx
xor    %rcx,%rax
movq   %rax,%xmm1
mulsd  %xmm2,%xmm1
movsd  0xe59(%rip),%xmm2
addsd  %xmm2,%xmm1
mulsd  %xmm1,%xmm0
movsd  %xmm0,-0x20(%rbp)
movsd  -0x20(%rbp),%xmm0
movsd  -0x18(%rbp),%xmm1
mulsd  -0x20(%rbp),%xmm1
movsd  -0x20(%rbp),%xmm2
movq   %xmm1,%rax
movabs $0x8000000000000000,%rcx
xor    %rcx,%rax
movq   %rax,%xmm1
mulsd  %xmm2,%xmm1
movsd  0xe15(%rip),%xmm2
addsd  %xmm2,%xmm1
mulsd  %xmm1,%xmm0
movsd  %xmm0,-0x20(%rbp)
movsd  -0x20(%rbp),%xmm0
movsd  -0x18(%rbp),%xmm1
mulsd  -0x20(%rbp),%xmm1
movsd  -0x20(%rbp),%xmm2
movq   %xmm1,%rax
movabs $0x8000000000000000,%rcx
xor    %rcx,%rax
movq   %rax,%xmm1
mulsd  %xmm2,%xmm1
movsd  0xdd1(%rip),%xmm2
addsd  %xmm2,%xmm1
mulsd  %xmm1,%xmm0
movsd  %xmm0,-0x20(%rbp)
movsd  0xdb4(%rip),%xmm0
divsd  -0x20(%rbp),%xmm0
movsd  %xmm0,-0x20(%rbp)
movsd  -0x20(%rbp),%xmm0
pop    %rbp
ret

x86 assembly (clang, -O2):
<AURAE_sqrtd>:
ret

LLVM IR (-O0):
define double @AURAE_sqrtd(double %0) {
%2 = alloca double
%3 = alloca i64
%4 = alloca double
%5 = alloca double
%6 = alloca float
%7 = alloca double
store double %0, double* %2
store double 1.500000e+00, double* %7
%8 = load double, double* %2
%9 = fmul double %8, 5.000000e-01
store double %9, double* %4
%10 = load double, double* %2
%11 = fptrunc double %10 to float
store float %11, float* %6
%12 = bitcast float* %6 to i64*
%13 = load i64, i64* %12
store i64 %13, i64* %3
%14 = load i64, i64* %3
%15 = ashr i64 %14, 1
%16 = sub nsw i64 1597463174, %15
store i64 %16, i64* %3
%17 = load i64, i64* %3
%18 = and i64 %17, 2147483647
store i64 %18, i64* %3
%19 = bitcast i64* %3 to float*
%20 = load float, float* %19
store float %20, float* %6
%21 = load float, float* %6
%22 = fpext float %21 to double
store double %22, double* %5
%23 = load double, double* %5
%24 = load double, double* %4
%25 = load double, double* %5
%26 = fmul double %24, %25
%27 = load double, double* %5
%28 = fneg double %26
%29 = call double @llvm.fmuladd.f64(double %28, double %27, double 1.500000e+00)
%30 = fmul double %23, %29
store double %30, double* %5
%31 = load double, double* %5
%32 = load double, double* %4
%33 = load double, double* %5
%34 = fmul double %32, %33
%35 = load double, double* %5
%36 = fneg double %34
%37 = call double @llvm.fmuladd.f64(double %36, double %35, double 1.500000e+00)
%38 = fmul double %31, %37
store double %38, double* %5
%39 = load double, double* %5
%40 = load double, double* %4
%41 = load double, double* %5
%42 = fmul double %40, %41
%43 = load double, double* %5
%44 = fneg double %42
%45 = call double @llvm.fmuladd.f64(double %44, double %43, double 1.500000e+00)
%46 = fmul double %39, %45
store double %46, double* %5
%47 = load double, double* %5
%48 = fdiv double 1.000000e+00, %47
store double %48, double* %5
%49 = load double, double* %5
ret double %49
}

LLVM IR (-O2):
define double @AURAE_sqrtd(double %0) {
ret double poison
}