double heatindex(double F, double rh) {
  double rh2 = rh * rh;
  double f2 = F * F;
  double Hindex = -42.379 + 2.04901523 * F + 10.14333127 * rh -
                  0.22475541 * F * rh - 6.83783 * .001 * f2 -
                  5.481717 * .01 * rh2 + 1.22874 * .001 * f2 * rh +
                  8.5282 * .0001 * F * rh2 - 1.99 * .000001 * f2 * rh2;
  return Hindex;
}


x86 assembly (clang, -O0):
<heatindex>:
push   %rbp
mov    %rsp,%rbp
movsd  %xmm0,-0x8(%rbp)
movsd  %xmm1,-0x10(%rbp)
movsd  -0x10(%rbp),%xmm0
mulsd  -0x10(%rbp),%xmm0
movsd  %xmm0,-0x18(%rbp)
movsd  -0x8(%rbp),%xmm0
mulsd  -0x8(%rbp),%xmm0
movsd  %xmm0,-0x20(%rbp)
movsd  -0x8(%rbp),%xmm1
movsd  0xeff(%rip),%xmm0
mulsd  %xmm0,%xmm1
movsd  0xefb(%rip),%xmm0
addsd  %xmm0,%xmm1
movsd  -0x10(%rbp),%xmm0
movsd  0xeda(%rip),%xmm2
mulsd  %xmm2,%xmm0
addsd  %xmm1,%xmm0
movsd  0xec2(%rip),%xmm1
mulsd  -0x8(%rbp),%xmm1
movsd  -0x10(%rbp),%xmm2
movq   %xmm1,%rax
movabs $0x8000000000000000,%rcx
xor    %rcx,%rax
movq   %rax,%xmm1
mulsd  %xmm2,%xmm1
addsd  %xmm0,%xmm1
movsd  -0x20(%rbp),%xmm0
movsd  0xe84(%rip),%xmm2
mulsd  %xmm2,%xmm0
addsd  %xmm1,%xmm0
movsd  -0x18(%rbp),%xmm1
movsd  0xe67(%rip),%xmm2
mulsd  %xmm2,%xmm1
addsd  %xmm0,%xmm1
movsd  0xe4f(%rip),%xmm0
mulsd  -0x20(%rbp),%xmm0
movsd  -0x10(%rbp),%xmm2
mulsd  %xmm2,%xmm0
addsd  %xmm1,%xmm0
movsd  0xe2d(%rip),%xmm1
mulsd  -0x8(%rbp),%xmm1
movsd  -0x18(%rbp),%xmm2
mulsd  %xmm2,%xmm1
addsd  %xmm0,%xmm1
movsd  0xe0b(%rip),%xmm0
mulsd  -0x20(%rbp),%xmm0
movsd  -0x18(%rbp),%xmm2
movq   %xmm0,%rax
movabs $0x8000000000000000,%rcx
xor    %rcx,%rax
movq   %rax,%xmm0
mulsd  %xmm2,%xmm0
addsd  %xmm1,%xmm0
movsd  %xmm0,-0x28(%rbp)
movsd  -0x28(%rbp),%xmm0
pop    %rbp
ret

x86 assembly (clang, -O2):
<heatindex>:
movapd %xmm0,%xmm2
mulsd  %xmm0,%xmm2
movsd  0xef0(%rip),%xmm3
mulsd  %xmm0,%xmm3
addsd  0xeec(%rip),%xmm3
movsd  0xeec(%rip),%xmm4
mulsd  %xmm1,%xmm4
addsd  %xmm3,%xmm4
movsd  0xee4(%rip),%xmm3
mulsd  %xmm0,%xmm3
mulsd  %xmm1,%xmm3
movsd  0xeec(%rip),%xmm5
mulsd  %xmm2,%xmm5
mulsd  %xmm1,%xmm5
mulsd  %xmm1,%xmm1
addsd  %xmm4,%xmm3
movsd  0xec4(%rip),%xmm4
mulsd  %xmm2,%xmm4
addsd  %xmm3,%xmm4
movsd  0xebc(%rip),%xmm3
mulsd  %xmm1,%xmm3
addsd  %xmm4,%xmm3
addsd  %xmm3,%xmm5
mulsd  0xeb8(%rip),%xmm0
mulsd  %xmm1,%xmm0
addsd  %xmm5,%xmm0
mulsd  0xeb0(%rip),%xmm2
mulsd  %xmm1,%xmm2
addsd  %xmm2,%xmm0
ret

LLVM IR (-O0):
define double @heatindex(double %0, double %1) {
%3 = alloca double
%4 = alloca double
%5 = alloca double
%6 = alloca double
%7 = alloca double
store double %0, double* %3
store double %1, double* %4
%8 = load double, double* %4
%9 = load double, double* %4
%10 = fmul double %8, %9
store double %10, double* %5
%11 = load double, double* %3
%12 = load double, double* %3
%13 = fmul double %11, %12
store double %13, double* %6
%14 = load double, double* %3
%15 = call double @llvm.fmuladd.f64(double 0x4000646218CED8EC, double %14, double -4.237900e+01)
%16 = load double, double* %4
%17 = call double @llvm.fmuladd.f64(double 0x40244962B75A49CD, double %16, double %15)
%18 = load double, double* %3
%19 = fmul double 0x3FCCC4C907C647F8, %18
%20 = load double, double* %4
%21 = fneg double %19
%22 = call double @llvm.fmuladd.f64(double %21, double %20, double %17)
%23 = load double, double* %6
%24 = call double @llvm.fmuladd.f64(double 0xBF7C01FC039C16CD, double %23, double %22)
%25 = load double, double* %5
%26 = call double @llvm.fmuladd.f64(double 0xBFAC10FF00D18C24, double %25, double %24)
%27 = load double, double* %6
%28 = fmul double 0x3F5421B58760DCE4, %27
%29 = load double, double* %4
%30 = call double @llvm.fmuladd.f64(double %28, double %29, double %26)
%31 = load double, double* %3
%32 = fmul double 8.528200e-04, %31
%33 = load double, double* %5
%34 = call double @llvm.fmuladd.f64(double %32, double %33, double %30)
%35 = load double, double* %6
%36 = fmul double 1.990000e-06, %35
%37 = load double, double* %5
%38 = fneg double %36
%39 = call double @llvm.fmuladd.f64(double %38, double %37, double %34)
store double %39, double* %7
%40 = load double, double* %7
ret double %40
}

LLVM IR (-O2):
define double @heatindex(double %0, double %1) {
%3 = fmul double %1, %1
%4 = fmul double %0, %0
%5 = tail call double @llvm.fmuladd.f64(double %0, double 0x4000646218CED8EC, double -4.237900e+01)
%6 = tail call double @llvm.fmuladd.f64(double %1, double 0x40244962B75A49CD, double %5)
%7 = fmul double %0, 0xBFCCC4C907C647F8
%8 = tail call double @llvm.fmuladd.f64(double %7, double %1, double %6)
%9 = tail call double @llvm.fmuladd.f64(double %4, double 0xBF7C01FC039C16CD, double %8)
%10 = tail call double @llvm.fmuladd.f64(double %3, double 0xBFAC10FF00D18C24, double %9)
%11 = fmul double %4, 0x3F5421B58760DCE4
%12 = tail call double @llvm.fmuladd.f64(double %11, double %1, double %10)
%13 = fmul double %0, 8.528200e-04
%14 = tail call double @llvm.fmuladd.f64(double %13, double %3, double %12)
%15 = fmul double %4, -1.990000e-06
%16 = tail call double @llvm.fmuladd.f64(double %15, double %3, double %14)
ret double %16
}