double sin(double x) {
  static const double a0 = 1.0, a1 = -1.666666666640169148537065260055e-1,
                      a2 = 8.333333316490113523036717102793e-3,
                      a3 = -1.984126600659171392655484413285e-4,
                      a4 = 2.755690114917374804474016589137e-6,
                      a5 = -2.502845227292692953118686710787e-8,
                      a6 = 1.538730635926417598443354215485e-10;
  double x2 = x * x;
  return x *
         (a0 +
          x2 * (a1 + x2 * (a2 + x2 * (a3 + x2 * (a4 + x2 * (a5 + x2 * a6))))));
}


x86 assembly (clang, -O0):
<sin>:
push   %rbp
mov    %rsp,%rbp
movsd  %xmm0,-0x8(%rbp)
movsd  -0x8(%rbp),%xmm0
mulsd  -0x8(%rbp),%xmm0
movsd  %xmm0,-0x10(%rbp)
movsd  -0x8(%rbp),%xmm0
movsd  -0x10(%rbp),%xmm1
movsd  -0x10(%rbp),%xmm2
movsd  -0x10(%rbp),%xmm3
movsd  -0x10(%rbp),%xmm4
movsd  -0x10(%rbp),%xmm5
movsd  -0x10(%rbp),%xmm6
movsd  0xee5(%rip),%xmm7
mulsd  %xmm7,%xmm6
movsd  0xee1(%rip),%xmm7
addsd  %xmm7,%xmm6
mulsd  %xmm6,%xmm5
movsd  0xec1(%rip),%xmm6
addsd  %xmm6,%xmm5
mulsd  %xmm5,%xmm4
movsd  0xea9(%rip),%xmm5
addsd  %xmm5,%xmm4
mulsd  %xmm4,%xmm3
movsd  0xe91(%rip),%xmm4
addsd  %xmm4,%xmm3
mulsd  %xmm3,%xmm2
movsd  0xe79(%rip),%xmm3
addsd  %xmm3,%xmm2
mulsd  %xmm2,%xmm1
movsd  0xe61(%rip),%xmm2
addsd  %xmm2,%xmm1
mulsd  %xmm1,%xmm0
pop    %rbp
ret

x86 assembly (clang, -O2):
<sin>:
movapd %xmm0,%xmm1
mulsd  %xmm0,%xmm1
movsd  0xef0(%rip),%xmm2
mulsd  %xmm1,%xmm2
addsd  0xeec(%rip),%xmm2
mulsd  %xmm1,%xmm2
addsd  0xee8(%rip),%xmm2
mulsd  %xmm1,%xmm2
addsd  0xee4(%rip),%xmm2
mulsd  %xmm1,%xmm2
addsd  0xee0(%rip),%xmm2
mulsd  %xmm1,%xmm2
addsd  0xedc(%rip),%xmm2
mulsd  %xmm1,%xmm2
addsd  0xed8(%rip),%xmm2
mulsd  %xmm2,%xmm0
ret

LLVM IR (-O0):
@sin.a0 = internal constant double 1.000000e+00
@sin.a1 = internal constant double 0xBFC555555553E06A
@sin.a2 = internal constant double 0x3F811111107CE982
@sin.a3 = internal constant double 0xBF2A019FC5AE4E82
@sin.a4 = internal constant double 0x3EC71DCCA975860A
@sin.a5 = internal constant double 0xBE5ADFC4C151EF2E
@sin.a6 = internal constant double 0x3DE525ED57FDCB8D
define double @sin(double %0) {
%2 = alloca double
%3 = alloca double
store double %0, double* %2
%4 = load double, double* %2
%5 = load double, double* %2
%6 = fmul double %4, %5
store double %6, double* %3
%7 = load double, double* %2
%8 = load double, double* %3
%9 = load double, double* %3
%10 = load double, double* %3
%11 = load double, double* %3
%12 = load double, double* %3
%13 = load double, double* %3
%14 = call double @llvm.fmuladd.f64(double %13, double 0x3DE525ED57FDCB8D, double 0xBE5ADFC4C151EF2E)
%15 = call double @llvm.fmuladd.f64(double %12, double %14, double 0x3EC71DCCA975860A)
%16 = call double @llvm.fmuladd.f64(double %11, double %15, double 0xBF2A019FC5AE4E82)
%17 = call double @llvm.fmuladd.f64(double %10, double %16, double 0x3F811111107CE982)
%18 = call double @llvm.fmuladd.f64(double %9, double %17, double 0xBFC555555553E06A)
%19 = call double @llvm.fmuladd.f64(double %8, double %18, double 1.000000e+00)
%20 = fmul double %7, %19
ret double %20
}

LLVM IR (-O2):
define double @sin(double %0) {
%2 = fmul double %0, %0
%3 = tail call double @llvm.fmuladd.f64(double %2, double 0x3DE525ED57FDCB8D, double 0xBE5ADFC4C151EF2E)
%4 = tail call double @llvm.fmuladd.f64(double %2, double %3, double 0x3EC71DCCA975860A)
%5 = tail call double @llvm.fmuladd.f64(double %2, double %4, double 0xBF2A019FC5AE4E82)
%6 = tail call double @llvm.fmuladd.f64(double %2, double %5, double 0x3F811111107CE982)
%7 = tail call double @llvm.fmuladd.f64(double %2, double %6, double 0xBFC555555553E06A)
%8 = tail call double @llvm.fmuladd.f64(double %2, double %7, double 1.000000e+00)
%9 = fmul double %8, %0
ret double %9
}