void unrefractLT15(double pr, double tr, double aa, double *ta) {
  double aadeg = ((aa)*180. / 3.141592653589793);
  double r, a, b;
  a = ((2e-5 * aadeg + 1.96e-2) * aadeg + 1.594e-1) * pr;
  b = (273 + tr) * ((8.45e-2 * aadeg + 5.05e-1) * aadeg + 1);
  r = ((a / b) * 3.141592653589793 / 180.);
  *ta = (aa < 0 && r < 0) ? aa : aa - r;
}


x86 assembly (clang, -O0):
<unrefractLT15>:
push   %rbp
mov    %rsp,%rbp
movsd  %xmm0,-0x8(%rbp)
movsd  %xmm1,-0x10(%rbp)
movsd  %xmm2,-0x18(%rbp)
mov    %rdi,-0x20(%rbp)
movsd  0xee1(%rip),%xmm0
mulsd  -0x18(%rbp),%xmm0
movsd  0xedc(%rip),%xmm1
divsd  %xmm1,%xmm0
movsd  %xmm0,-0x28(%rbp)
movsd  -0x28(%rbp),%xmm0
movsd  0xef6(%rip),%xmm1
mulsd  %xmm1,%xmm0
movsd  0xef2(%rip),%xmm1
addsd  %xmm1,%xmm0
movsd  -0x28(%rbp),%xmm1
mulsd  %xmm1,%xmm0
movsd  0xecd(%rip),%xmm1
addsd  %xmm1,%xmm0
mulsd  -0x8(%rbp),%xmm0
movsd  %xmm0,-0x38(%rbp)
movsd  0xeaf(%rip),%xmm0
addsd  -0x10(%rbp),%xmm0
movsd  -0x28(%rbp),%xmm1
movsd  0xe8d(%rip),%xmm2
mulsd  %xmm2,%xmm1
movsd  0xe89(%rip),%xmm2
addsd  %xmm2,%xmm1
movsd  -0x28(%rbp),%xmm2
mulsd  %xmm2,%xmm1
movsd  0xe64(%rip),%xmm2
addsd  %xmm2,%xmm1
mulsd  %xmm1,%xmm0
movsd  %xmm0,-0x40(%rbp)
movsd  -0x38(%rbp),%xmm0
divsd  -0x40(%rbp),%xmm0
movsd  0xe3d(%rip),%xmm1
mulsd  %xmm1,%xmm0
movsd  0xe29(%rip),%xmm1
divsd  %xmm1,%xmm0
movsd  %xmm0,-0x30(%rbp)
xorps  %xmm0,%xmm0
ucomisd -0x18(%rbp),%xmm0
jbe    120b <unrefractLT15+0x10b>
xorps  %xmm0,%xmm0
ucomisd -0x30(%rbp),%xmm0
jbe    120b <unrefractLT15+0x10b>
movsd  -0x18(%rbp),%xmm0
movsd  %xmm0,-0x48(%rbp)
jmp    121a <unrefractLT15+0x11a>
movsd  -0x18(%rbp),%xmm0
subsd  -0x30(%rbp),%xmm0
movsd  %xmm0,-0x48(%rbp)
movsd  -0x48(%rbp),%xmm0
mov    -0x20(%rbp),%rax
movsd  %xmm0,(%rax)
pop    %rbp
ret

x86 assembly (clang, -O2):
<unrefractLT15>:
movsd  0xef8(%rip),%xmm4
movapd %xmm2,%xmm5
mulsd  %xmm4,%xmm5
movsd  0xef0(%rip),%xmm6
divsd  %xmm6,%xmm5
movsd  0xeec(%rip),%xmm3
mulsd  %xmm5,%xmm3
addsd  0xee8(%rip),%xmm3
mulsd  %xmm5,%xmm3
addsd  0xee4(%rip),%xmm3
addsd  0xee4(%rip),%xmm1
movsd  0xee4(%rip),%xmm7
mulsd  %xmm5,%xmm7
addsd  0xee0(%rip),%xmm7
mulsd  %xmm0,%xmm3
mulsd  %xmm5,%xmm7
addsd  0xed8(%rip),%xmm7
mulsd  %xmm1,%xmm7
divsd  %xmm7,%xmm3
mulsd  %xmm6,%xmm3
divsd  %xmm4,%xmm3
xorpd  %xmm0,%xmm0
movapd %xmm2,%xmm1
cmpltsd %xmm0,%xmm1
maxsd  %xmm3,%xmm0
andpd  %xmm1,%xmm0
andnpd %xmm3,%xmm1
orpd   %xmm1,%xmm0
subsd  %xmm0,%xmm2
movsd  %xmm2,(%rdi)
ret

LLVM IR (-O0):
define void @unrefractLT15(double %0, double %1, double %2, double* %3) {
%5 = alloca double
%6 = alloca double
%7 = alloca double
%8 = alloca double*
%9 = alloca double
%10 = alloca double
%11 = alloca double
%12 = alloca double
store double %0, double* %5
store double %1, double* %6
store double %2, double* %7
store double* %3, double** %8
%13 = load double, double* %7
%14 = fmul double %13, 1.800000e+02
%15 = fdiv double %14, 0x400921FB54442D18
store double %15, double* %9
%16 = load double, double* %9
%17 = call double @llvm.fmuladd.f64(double 2.000000e-05, double %16, double 1.960000e-02)
%18 = load double, double* %9
%19 = call double @llvm.fmuladd.f64(double %17, double %18, double 1.594000e-01)
%20 = load double, double* %5
%21 = fmul double %19, %20
store double %21, double* %11
%22 = load double, double* %6
%23 = fadd double 2.730000e+02, %22
%24 = load double, double* %9
%25 = call double @llvm.fmuladd.f64(double 8.450000e-02, double %24, double 5.050000e-01)
%26 = load double, double* %9
%27 = call double @llvm.fmuladd.f64(double %25, double %26, double 1.000000e+00)
%28 = fmul double %23, %27
store double %28, double* %12
%29 = load double, double* %11
%30 = load double, double* %12
%31 = fdiv double %29, %30
%32 = fmul double %31, 0x400921FB54442D18
%33 = fdiv double %32, 1.800000e+02
store double %33, double* %10
%34 = load double, double* %7
%35 = fcmp olt double %34, 0.000000e+00
br i1 %35, label %36, label %41
36: ; preds = %4
%37 = load double, double* %10
%38 = fcmp olt double %37, 0.000000e+00
br i1 %38, label %39, label %41
39: ; preds = %36
%40 = load double, double* %7
br label %45
41: ; preds = %36, %4
%42 = load double, double* %7
%43 = load double, double* %10
%44 = fsub double %42, %43
br label %45
45: ; preds = %41, %39
%46 = phi double [ %40, %39 ], [ %44, %41 ]
%47 = load double*, double** %8
store double %46, double* %47
ret void
}

LLVM IR (-O2):
define void @unrefractLT15(double %0, double %1, double %2, double* nocapture writeonly %3) {
%5 = fmul double %2, 1.800000e+02
%6 = fdiv double %5, 0x400921FB54442D18
%7 = tail call double @llvm.fmuladd.f64(double %6, double 2.000000e-05, double 1.960000e-02)
%8 = tail call double @llvm.fmuladd.f64(double %7, double %6, double 1.594000e-01)
%9 = fmul double %8, %0
%10 = fadd double %1, 2.730000e+02
%11 = tail call double @llvm.fmuladd.f64(double %6, double 8.450000e-02, double 5.050000e-01)
%12 = tail call double @llvm.fmuladd.f64(double %11, double %6, double 1.000000e+00)
%13 = fmul double %10, %12
%14 = fdiv double %9, %13
%15 = fmul double %14, 0x400921FB54442D18
%16 = fdiv double %15, 1.800000e+02
%17 = fcmp olt double %2, 0.000000e+00
%18 = fcmp olt double %16, 0.000000e+00
%19 = select i1 %17, i1 %18, i1 false
%20 = select i1 %19, double 0.000000e+00, double %16
%21 = fsub double %2, %20
store double %21, double* %3
ret void
}