double incirclefast(double *pa, double *pb, double *pc, double *pd) {
  double adx, ady, bdx, bdy, cdx, cdy;
  double abdet, bcdet, cadet;
  double alift, blift, clift;
  adx = pa[0] - pd[0];
  ady = pa[1] - pd[1];
  bdx = pb[0] - pd[0];
  bdy = pb[1] - pd[1];
  cdx = pc[0] - pd[0];
  cdy = pc[1] - pd[1];
  abdet = adx * bdy - bdx * ady;
  bcdet = bdx * cdy - cdx * bdy;
  cadet = cdx * ady - adx * cdy;
  alift = adx * adx + ady * ady;
  blift = bdx * bdx + bdy * bdy;
  clift = cdx * cdx + cdy * cdy;
  return alift * bcdet + blift * cadet + clift * abdet;
}


x86 assembly (clang, -O0):
<incirclefast>:
push   %rbp
mov    %rsp,%rbp
mov    %rdi,-0x8(%rbp)
mov    %rsi,-0x10(%rbp)
mov    %rdx,-0x18(%rbp)
mov    %rcx,-0x20(%rbp)
mov    -0x8(%rbp),%rax
movsd  (%rax),%xmm0
mov    -0x20(%rbp),%rax
subsd  (%rax),%xmm0
movsd  %xmm0,-0x28(%rbp)
mov    -0x8(%rbp),%rax
movsd  0x8(%rax),%xmm0
mov    -0x20(%rbp),%rax
subsd  0x8(%rax),%xmm0
movsd  %xmm0,-0x30(%rbp)
mov    -0x10(%rbp),%rax
movsd  (%rax),%xmm0
mov    -0x20(%rbp),%rax
subsd  (%rax),%xmm0
movsd  %xmm0,-0x38(%rbp)
mov    -0x10(%rbp),%rax
movsd  0x8(%rax),%xmm0
mov    -0x20(%rbp),%rax
subsd  0x8(%rax),%xmm0
movsd  %xmm0,-0x40(%rbp)
mov    -0x18(%rbp),%rax
movsd  (%rax),%xmm0
mov    -0x20(%rbp),%rax
subsd  (%rax),%xmm0
movsd  %xmm0,-0x48(%rbp)
mov    -0x18(%rbp),%rax
movsd  0x8(%rax),%xmm0
mov    -0x20(%rbp),%rax
subsd  0x8(%rax),%xmm0
movsd  %xmm0,-0x50(%rbp)
movsd  -0x28(%rbp),%xmm0
movsd  -0x40(%rbp),%xmm2
movsd  -0x38(%rbp),%xmm1
mulsd  -0x30(%rbp),%xmm1
movq   %xmm1,%rax
movabs $0x8000000000000000,%rcx
xor    %rcx,%rax
movq   %rax,%xmm1
mulsd  %xmm2,%xmm0
addsd  %xmm1,%xmm0
movsd  %xmm0,-0x58(%rbp)
movsd  -0x38(%rbp),%xmm0
movsd  -0x50(%rbp),%xmm2
movsd  -0x48(%rbp),%xmm1
mulsd  -0x40(%rbp),%xmm1
movq   %xmm1,%rax
movabs $0x8000000000000000,%rcx
xor    %rcx,%rax
movq   %rax,%xmm1
mulsd  %xmm2,%xmm0
addsd  %xmm1,%xmm0
movsd  %xmm0,-0x60(%rbp)
movsd  -0x48(%rbp),%xmm0
movsd  -0x30(%rbp),%xmm2
movsd  -0x28(%rbp),%xmm1
mulsd  -0x50(%rbp),%xmm1
movq   %xmm1,%rax
movabs $0x8000000000000000,%rcx
xor    %rcx,%rax
movq   %rax,%xmm1
mulsd  %xmm2,%xmm0
addsd  %xmm1,%xmm0
movsd  %xmm0,-0x68(%rbp)
movsd  -0x28(%rbp),%xmm0
movsd  -0x28(%rbp),%xmm2
movsd  -0x30(%rbp),%xmm1
mulsd  -0x30(%rbp),%xmm1
mulsd  %xmm2,%xmm0
addsd  %xmm1,%xmm0
movsd  %xmm0,-0x70(%rbp)
movsd  -0x38(%rbp),%xmm0
movsd  -0x38(%rbp),%xmm2
movsd  -0x40(%rbp),%xmm1
mulsd  -0x40(%rbp),%xmm1
mulsd  %xmm2,%xmm0
addsd  %xmm1,%xmm0
movsd  %xmm0,-0x78(%rbp)
movsd  -0x48(%rbp),%xmm0
movsd  -0x48(%rbp),%xmm2
movsd  -0x50(%rbp),%xmm1
mulsd  -0x50(%rbp),%xmm1
mulsd  %xmm2,%xmm0
addsd  %xmm1,%xmm0
movsd  %xmm0,-0x80(%rbp)
movsd  -0x70(%rbp),%xmm1
movsd  -0x60(%rbp),%xmm2
movsd  -0x78(%rbp),%xmm0
mulsd  -0x68(%rbp),%xmm0
mulsd  %xmm2,%xmm1
addsd  %xmm0,%xmm1
movsd  -0x80(%rbp),%xmm0
movsd  -0x58(%rbp),%xmm2
mulsd  %xmm2,%xmm0
addsd  %xmm1,%xmm0
pop    %rbp
ret

x86 assembly (clang, -O2):
<incirclefast>:
movsd  (%rdi),%xmm1
movsd  0x8(%rdi),%xmm9
movsd  (%rcx),%xmm4
movsd  0x8(%rcx),%xmm5
subsd  %xmm4,%xmm1
subsd  %xmm5,%xmm9
movsd  (%rsi),%xmm3
movsd  0x8(%rsi),%xmm0
movhpd (%rdx),%xmm3
unpcklpd %xmm4,%xmm4
subpd  %xmm4,%xmm3
movhpd 0x8(%rdx),%xmm0
unpcklpd %xmm5,%xmm5
subpd  %xmm5,%xmm0
movapd %xmm9,%xmm5
mulsd  %xmm3,%xmm5
movapd %xmm1,%xmm8
mulsd  %xmm0,%xmm8
subsd  %xmm5,%xmm8
movapd %xmm3,%xmm5
movapd %xmm3,%xmm6
unpcklpd %xmm9,%xmm6
mulpd  %xmm3,%xmm6
unpckhpd %xmm3,%xmm3
movapd %xmm0,%xmm7
movapd 0xe89(%rip),%xmm4
xorpd  %xmm1,%xmm4
movapd %xmm0,%xmm2
unpcklpd %xmm4,%xmm2
mulpd  %xmm0,%xmm2
mulsd  %xmm3,%xmm0
unpckhpd %xmm7,%xmm7
mulsd  %xmm7,%xmm5
subsd  %xmm0,%xmm5
mulsd  %xmm9,%xmm9
mulsd  %xmm1,%xmm1
addsd  %xmm9,%xmm1
mulsd  %xmm5,%xmm1
addpd  %xmm2,%xmm6
mulsd  %xmm7,%xmm7
mulsd  %xmm3,%xmm3
addsd  %xmm7,%xmm3
mulsd  %xmm8,%xmm3
movapd %xmm6,%xmm0
unpckhpd %xmm6,%xmm0
mulsd  %xmm6,%xmm0
addsd  %xmm1,%xmm0
addsd  %xmm3,%xmm0
ret

LLVM IR (-O0):
define double @incirclefast(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
%13 = alloca double
%14 = alloca double
%15 = alloca double
%16 = alloca double
%17 = alloca double
%18 = alloca double
%19 = alloca double
%20 = alloca double
store double* %0, double** %5
store double* %1, double** %6
store double* %2, double** %7
store double* %3, double** %8
%21 = load double*, double** %5
%22 = getelementptr inbounds double, double* %21, i64 0
%23 = load double, double* %22
%24 = load double*, double** %8
%25 = getelementptr inbounds double, double* %24, i64 0
%26 = load double, double* %25
%27 = fsub double %23, %26
store double %27, double* %9
%28 = load double*, double** %5
%29 = getelementptr inbounds double, double* %28, i64 1
%30 = load double, double* %29
%31 = load double*, double** %8
%32 = getelementptr inbounds double, double* %31, i64 1
%33 = load double, double* %32
%34 = fsub double %30, %33
store double %34, double* %10
%35 = load double*, double** %6
%36 = getelementptr inbounds double, double* %35, i64 0
%37 = load double, double* %36
%38 = load double*, double** %8
%39 = getelementptr inbounds double, double* %38, i64 0
%40 = load double, double* %39
%41 = fsub double %37, %40
store double %41, double* %11
%42 = load double*, double** %6
%43 = getelementptr inbounds double, double* %42, i64 1
%44 = load double, double* %43
%45 = load double*, double** %8
%46 = getelementptr inbounds double, double* %45, i64 1
%47 = load double, double* %46
%48 = fsub double %44, %47
store double %48, double* %12
%49 = load double*, double** %7
%50 = getelementptr inbounds double, double* %49, i64 0
%51 = load double, double* %50
%52 = load double*, double** %8
%53 = getelementptr inbounds double, double* %52, i64 0
%54 = load double, double* %53
%55 = fsub double %51, %54
store double %55, double* %13
%56 = load double*, double** %7
%57 = getelementptr inbounds double, double* %56, i64 1
%58 = load double, double* %57
%59 = load double*, double** %8
%60 = getelementptr inbounds double, double* %59, i64 1
%61 = load double, double* %60
%62 = fsub double %58, %61
store double %62, double* %14
%63 = load double, double* %9
%64 = load double, double* %12
%65 = load double, double* %11
%66 = load double, double* %10
%67 = fmul double %65, %66
%68 = fneg double %67
%69 = call double @llvm.fmuladd.f64(double %63, double %64, double %68)
store double %69, double* %15
%70 = load double, double* %11
%71 = load double, double* %14
%72 = load double, double* %13
%73 = load double, double* %12
%74 = fmul double %72, %73
%75 = fneg double %74
%76 = call double @llvm.fmuladd.f64(double %70, double %71, double %75)
store double %76, double* %16
%77 = load double, double* %13
%78 = load double, double* %10
%79 = load double, double* %9
%80 = load double, double* %14
%81 = fmul double %79, %80
%82 = fneg double %81
%83 = call double @llvm.fmuladd.f64(double %77, double %78, double %82)
store double %83, double* %17
%84 = load double, double* %9
%85 = load double, double* %9
%86 = load double, double* %10
%87 = load double, double* %10
%88 = fmul double %86, %87
%89 = call double @llvm.fmuladd.f64(double %84, double %85, double %88)
store double %89, double* %18
%90 = load double, double* %11
%91 = load double, double* %11
%92 = load double, double* %12
%93 = load double, double* %12
%94 = fmul double %92, %93
%95 = call double @llvm.fmuladd.f64(double %90, double %91, double %94)
store double %95, double* %19
%96 = load double, double* %13
%97 = load double, double* %13
%98 = load double, double* %14
%99 = load double, double* %14
%100 = fmul double %98, %99
%101 = call double @llvm.fmuladd.f64(double %96, double %97, double %100)
store double %101, double* %20
%102 = load double, double* %18
%103 = load double, double* %16
%104 = load double, double* %19
%105 = load double, double* %17
%106 = fmul double %104, %105
%107 = call double @llvm.fmuladd.f64(double %102, double %103, double %106)
%108 = load double, double* %20
%109 = load double, double* %15
%110 = call double @llvm.fmuladd.f64(double %108, double %109, double %107)
ret double %110
}

LLVM IR (-O2):
define double @incirclefast(double* nocapture %0, double* nocapture %1, double* nocapture %2, double* nocapture %3) {
%5 = load double, double* %0
%6 = load double, double* %3
%7 = fsub double %5, %6
%8 = getelementptr inbounds double, double* %0, i64 1
%9 = load double, double* %8
%10 = getelementptr inbounds double, double* %3, i64 1
%11 = load double, double* %10
%12 = fsub double %9, %11
%13 = load double, double* %1
%14 = getelementptr inbounds double, double* %1, i64 1
%15 = load double, double* %14
%16 = load double, double* %2
%17 = insertelement <2 x double> poison, double %13, i64 0
%18 = insertelement <2 x double> %17, double %16, i64 1
%19 = insertelement <2 x double> poison, double %6, i64 0
%20 = shufflevector <2 x double> %19, <2 x double> poison, <2 x i32> zeroinitializer
%21 = fsub <2 x double> %18, %20
%22 = getelementptr inbounds double, double* %2, i64 1
%23 = load double, double* %22
%24 = insertelement <2 x double> poison, double %15, i64 0
%25 = insertelement <2 x double> %24, double %23, i64 1
%26 = insertelement <2 x double> poison, double %11, i64 0
%27 = shufflevector <2 x double> %26, <2 x double> poison, <2 x i32> zeroinitializer
%28 = fsub <2 x double> %25, %27
%29 = extractelement <2 x double> %21, i64 0
%30 = fneg double %29
%31 = fmul double %12, %30
%32 = extractelement <2 x double> %28, i64 0
%33 = tail call double @llvm.fmuladd.f64(double %7, double %32, double %31)
%34 = extractelement <2 x double> %21, i64 1
%35 = fneg double %34
%36 = fmul double %32, %35
%37 = extractelement <2 x double> %28, i64 1
%38 = tail call double @llvm.fmuladd.f64(double %29, double %37, double %36)
%39 = fneg double %7
%40 = fmul double %12, %12
%41 = tail call double @llvm.fmuladd.f64(double %7, double %7, double %40)
%42 = insertelement <2 x double> %28, double %39, i64 1
%43 = fmul <2 x double> %28, %42
%44 = insertelement <2 x double> %21, double %12, i64 1
%45 = call <2 x double> @llvm.fmuladd.v2f64(<2 x double> %21, <2 x double> %44, <2 x double> %43)
%46 = fmul double %37, %37
%47 = tail call double @llvm.fmuladd.f64(double %34, double %34, double %46)
%48 = shufflevector <2 x double> %45, <2 x double> poison, <2 x i32> <i32 1, i32 undef>
%49 = fmul <2 x double> %45, %48
%50 = extractelement <2 x double> %49, i64 0
%51 = tail call double @llvm.fmuladd.f64(double %41, double %38, double %50)
%52 = tail call double @llvm.fmuladd.f64(double %47, double %33, double %51)
ret double %52
}