void Nutation(double NutLon, double NutObl, double Obl, double *RA,
              double *Decl) {
  double cosObl, sinObl;
  double cosRA, sinRA;
  if (fabs(*Decl) < 1.54) {
    cosObl = cos(Obl);
    sinObl = sin(Obl);
    cosRA = cos(*RA);
    sinRA = sin(*RA);
    *RA += (cosObl + sinObl * sinRA * tan(*Decl)) * NutLon;
    *RA -= (cosRA * tan(*Decl)) * NutObl;
    *Decl += (sinObl * cosRA) * NutLon + (sinRA)*NutObl;
  } else {
    EclToEqu(*RA, *Decl, -Obl, RA, Decl);
    EclToEqu(*RA + NutLon, *Decl, Obl + NutObl, RA, Decl);
  }
}


x86 assembly (clang, -O0):
<Nutation>:
push   %rbp
mov    %rsp,%rbp
sub    $0x60,%rsp
movsd  %xmm0,-0x8(%rbp)
movsd  %xmm1,-0x10(%rbp)
movsd  %xmm2,-0x18(%rbp)
mov    %rdi,-0x20(%rbp)
mov    %rsi,-0x28(%rbp)
mov    -0x28(%rbp),%rax
movsd  (%rax),%xmm1
movaps 0xea2(%rip),%xmm0
pand   %xmm0,%xmm1
movsd  0xe86(%rip),%xmm0
ucomisd %xmm1,%xmm0
jbe    129f <Nutation+0x15f>
movsd  -0x18(%rbp),%xmm0
call   1060 <cos@plt>
movsd  %xmm0,-0x30(%rbp)
movsd  -0x18(%rbp),%xmm0
call   1040 <sin@plt>
movsd  %xmm0,-0x38(%rbp)
mov    -0x20(%rbp),%rax
movsd  (%rax),%xmm0
call   1060 <cos@plt>
movsd  %xmm0,-0x40(%rbp)
mov    -0x20(%rbp),%rax
movsd  (%rax),%xmm0
call   1040 <sin@plt>
movsd  %xmm0,-0x48(%rbp)
movsd  -0x30(%rbp),%xmm0
movsd  %xmm0,-0x60(%rbp)
movsd  -0x38(%rbp),%xmm0
mulsd  -0x48(%rbp),%xmm0
movsd  %xmm0,-0x58(%rbp)
mov    -0x28(%rbp),%rax
movsd  (%rax),%xmm0
call   1050 <tan@plt>
movsd  -0x60(%rbp),%xmm1
movaps %xmm0,%xmm2
movsd  -0x58(%rbp),%xmm0
mulsd  %xmm2,%xmm0
addsd  %xmm1,%xmm0
movsd  -0x8(%rbp),%xmm2
mov    -0x20(%rbp),%rax
movsd  (%rax),%xmm1
mulsd  %xmm2,%xmm0
addsd  %xmm1,%xmm0
movsd  %xmm0,(%rax)
movsd  -0x40(%rbp),%xmm0
movsd  %xmm0,-0x50(%rbp)
mov    -0x28(%rbp),%rax
movsd  (%rax),%xmm0
call   1050 <tan@plt>
movaps %xmm0,%xmm1
movsd  -0x50(%rbp),%xmm0
mulsd  %xmm1,%xmm0
movsd  -0x10(%rbp),%xmm2
mov    -0x20(%rbp),%rax
movsd  (%rax),%xmm1
movq   %xmm0,%rcx
movabs $0x8000000000000000,%rdx
xor    %rdx,%rcx
movq   %rcx,%xmm0
mulsd  %xmm2,%xmm0
addsd  %xmm1,%xmm0
movsd  %xmm0,(%rax)
movsd  -0x38(%rbp),%xmm0
mulsd  -0x40(%rbp),%xmm0
movsd  -0x8(%rbp),%xmm2
movsd  -0x48(%rbp),%xmm1
mulsd  -0x10(%rbp),%xmm1
mulsd  %xmm2,%xmm0
addsd  %xmm1,%xmm0
mov    -0x28(%rbp),%rax
addsd  (%rax),%xmm0
movsd  %xmm0,(%rax)
jmp    1308 <Nutation+0x1c8>
mov    -0x20(%rbp),%rax
movsd  (%rax),%xmm0
mov    -0x28(%rbp),%rax
movsd  (%rax),%xmm1
movsd  -0x18(%rbp),%xmm2
movq   %xmm2,%rax
movabs $0x8000000000000000,%rcx
xor    %rcx,%rax
movq   %rax,%xmm2
mov    -0x20(%rbp),%rdi
mov    -0x28(%rbp),%rsi
mov    $0x3,%al
call   1030 <EclToEqu@plt>
mov    -0x20(%rbp),%rax
movsd  (%rax),%xmm0
addsd  -0x8(%rbp),%xmm0
mov    -0x28(%rbp),%rax
movsd  (%rax),%xmm1
movsd  -0x18(%rbp),%xmm2
addsd  -0x10(%rbp),%xmm2
mov    -0x20(%rbp),%rdi
mov    -0x28(%rbp),%rsi
mov    $0x3,%al
call   1030 <EclToEqu@plt>
add    $0x60,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<Nutation>:
push   %r14
push   %rbx
sub    $0x48,%rsp
mov    %rsi,%r14
mov    %rdi,%rbx
movaps %xmm2,%xmm3
movsd  %xmm1,0x20(%rsp)
movsd  %xmm0,0x8(%rsp)
movsd  (%rsi),%xmm1
movapd 0xe98(%rip),%xmm0
andpd  %xmm1,%xmm0
movsd  0xeac(%rip),%xmm2
ucomisd %xmm0,%xmm2
movaps %xmm3,0x10(%rsp)
jbe    124d <Nutation+0x10d>
movaps %xmm3,%xmm0
call   1060 <cos@plt>
movsd  %xmm0,0x30(%rsp)
movaps 0x10(%rsp),%xmm0
call   1040 <sin@plt>
movsd  %xmm0,0x10(%rsp)
movsd  (%rbx),%xmm0
call   1060 <cos@plt>
movsd  %xmm0,0x38(%rsp)
movsd  (%rbx),%xmm0
call   1040 <sin@plt>
movsd  %xmm0,0x40(%rsp)
movsd  0x10(%rsp),%xmm1
mulsd  %xmm0,%xmm1
movsd  %xmm1,0x28(%rsp)
movsd  (%r14),%xmm0
call   1050 <tan@plt>
mulsd  0x28(%rsp),%xmm0
addsd  0x30(%rsp),%xmm0
mulsd  0x8(%rsp),%xmm0
addsd  (%rbx),%xmm0
movsd  %xmm0,(%rbx)
movsd  (%r14),%xmm0
call   1050 <tan@plt>
movsd  (%rbx),%xmm1
movsd  0x38(%rsp),%xmm3
mulsd  %xmm3,%xmm0
movsd  0x20(%rsp),%xmm2
mulsd  %xmm2,%xmm0
subsd  %xmm0,%xmm1
movsd  %xmm1,(%rbx)
movsd  0x10(%rsp),%xmm0
mulsd  %xmm3,%xmm0
movsd  0x40(%rsp),%xmm1
mulsd  %xmm2,%xmm1
mulsd  0x8(%rsp),%xmm0
addsd  %xmm1,%xmm0
addsd  (%r14),%xmm0
movsd  %xmm0,(%r14)
add    $0x48,%rsp
pop    %rbx
pop    %r14
ret
movsd  (%rbx),%xmm0
movaps 0xdb8(%rip),%xmm2
xorps  %xmm3,%xmm2
mov    %rbx,%rdi
mov    %r14,%rsi
mov    $0x3,%al
call   1030 <EclToEqu@plt>
movsd  0x8(%rsp),%xmm0
addsd  (%rbx),%xmm0
movsd  (%r14),%xmm1
movsd  0x20(%rsp),%xmm2
addsd  0x10(%rsp),%xmm2
mov    %rbx,%rdi
mov    %r14,%rsi
mov    $0x3,%al
add    $0x48,%rsp
pop    %rbx
pop    %r14
jmp    1030 <EclToEqu@plt>

LLVM IR (-O0):
define void @Nutation(double %0, double %1, double %2, double* %3, double* %4) {
%6 = alloca double
%7 = alloca double
%8 = alloca double
%9 = alloca double*
%10 = alloca double*
%11 = alloca double
%12 = alloca double
%13 = alloca double
%14 = alloca double
store double %0, double* %6
store double %1, double* %7
store double %2, double* %8
store double* %3, double** %9
store double* %4, double** %10
%15 = load double*, double** %10
%16 = load double, double* %15
%17 = call double @llvm.fabs.f64(double %16)
%18 = fcmp olt double %17, 1.540000e+00
br i1 %18, label %19, label %63
19: ; preds = %5
%20 = load double, double* %8
%21 = call double @cos(double %20)
store double %21, double* %11
%22 = load double, double* %8
%23 = call double @sin(double %22)
store double %23, double* %12
%24 = load double*, double** %9
%25 = load double, double* %24
%26 = call double @cos(double %25)
store double %26, double* %13
%27 = load double*, double** %9
%28 = load double, double* %27
%29 = call double @sin(double %28)
store double %29, double* %14
%30 = load double, double* %11
%31 = load double, double* %12
%32 = load double, double* %14
%33 = fmul double %31, %32
%34 = load double*, double** %10
%35 = load double, double* %34
%36 = call double @tan(double %35)
%37 = call double @llvm.fmuladd.f64(double %33, double %36, double %30)
%38 = load double, double* %6
%39 = load double*, double** %9
%40 = load double, double* %39
%41 = call double @llvm.fmuladd.f64(double %37, double %38, double %40)
store double %41, double* %39
%42 = load double, double* %13
%43 = load double*, double** %10
%44 = load double, double* %43
%45 = call double @tan(double %44)
%46 = fmul double %42, %45
%47 = load double, double* %7
%48 = load double*, double** %9
%49 = load double, double* %48
%50 = fneg double %46
%51 = call double @llvm.fmuladd.f64(double %50, double %47, double %49)
store double %51, double* %48
%52 = load double, double* %12
%53 = load double, double* %13
%54 = fmul double %52, %53
%55 = load double, double* %6
%56 = load double, double* %14
%57 = load double, double* %7
%58 = fmul double %56, %57
%59 = call double @llvm.fmuladd.f64(double %54, double %55, double %58)
%60 = load double*, double** %10
%61 = load double, double* %60
%62 = fadd double %61, %59
store double %62, double* %60
br label %85
63: ; preds = %5
%64 = load double*, double** %9
%65 = load double, double* %64
%66 = load double*, double** %10
%67 = load double, double* %66
%68 = load double, double* %8
%69 = fneg double %68
%70 = load double*, double** %9
%71 = load double*, double** %10
%72 = call i32 (double, double, double, double*, double*, ...) bitcast (i32 (...)* @EclToEqu to i32 (double, double, double, double*, double*, ...)*)(double %65, double %67, double %69, double* %70, double* %71)
%73 = load double*, double** %9
%74 = load double, double* %73
%75 = load double, double* %6
%76 = fadd double %74, %75
%77 = load double*, double** %10
%78 = load double, double* %77
%79 = load double, double* %8
%80 = load double, double* %7
%81 = fadd double %79, %80
%82 = load double*, double** %9
%83 = load double*, double** %10
%84 = call i32 (double, double, double, double*, double*, ...) bitcast (i32 (...)* @EclToEqu to i32 (double, double, double, double*, double*, ...)*)(double %76, double %78, double %81, double* %82, double* %83)
br label %85
85: ; preds = %63, %19
ret void
}

LLVM IR (-O2):
define void @Nutation(double %0, double %1, double %2, double* %3, double* %4) {
%6 = load double, double* %4
%7 = tail call double @llvm.fabs.f64(double %6)
%8 = fcmp olt double %7, 1.540000e+00
br i1 %8, label %9, label %33
9: ; preds = %5
%10 = tail call double @cos(double %2)
%11 = tail call double @sin(double %2)
%12 = load double, double* %3
%13 = tail call double @cos(double %12)
%14 = load double, double* %3
%15 = tail call double @sin(double %14)
%16 = fmul double %11, %15
%17 = load double, double* %4
%18 = tail call double @tan(double %17)
%19 = tail call double @llvm.fmuladd.f64(double %16, double %18, double %10)
%20 = load double, double* %3
%21 = tail call double @llvm.fmuladd.f64(double %19, double %0, double %20)
store double %21, double* %3
%22 = load double, double* %4
%23 = tail call double @tan(double %22)
%24 = load double, double* %3
%25 = fneg double %13
%26 = fmul double %23, %25
%27 = tail call double @llvm.fmuladd.f64(double %26, double %1, double %24)
store double %27, double* %3
%28 = fmul double %11, %13
%29 = fmul double %15, %1
%30 = tail call double @llvm.fmuladd.f64(double %28, double %0, double %29)
%31 = load double, double* %4
%32 = fadd double %30, %31
store double %32, double* %4
br label %42
33: ; preds = %5
%34 = load double, double* %3
%35 = fneg double %2
%36 = tail call i32 (double, double, double, double*, double*, ...) bitcast (i32 (...)* @EclToEqu to i32 (double, double, double, double*, double*, ...)*)(double %34, double %6, double %35, double* %3, double* %4)
%37 = load double, double* %3
%38 = fadd double %37, %0
%39 = load double, double* %4
%40 = fadd double %1, %2
%41 = tail call i32 (double, double, double, double*, double*, ...) bitcast (i32 (...)* @EclToEqu to i32 (double, double, double, double*, double*, ...)*)(double %38, double %39, double %40, double* %3, double* %4)
br label %42
42: ; preds = %33, %9
ret void
}