void triorthocenter(a, b, c, orthocenter, cnum) double a[3];
double b[3];
double c[3];
double orthocenter[2];
double *cnum;
{
  double xba, yba, wba, xca, yca, wca;
  double balength, calength;
  double denominator;
  double xcirca, ycirca;
  xba = b[0] - a[0];
  yba = b[1] - a[1];
  wba = b[2] - a[2];
  xca = c[0] - a[0];
  yca = c[1] - a[1];
  wca = b[2] - a[2];
  balength = xba * xba + yba * yba - wba;
  calength = xca * xca + yca * yca - wca;
  *cnum = orient2d(b, c, a);
  denominator = 0.5 / (*cnum);
  xcirca = (yca * balength - yba * calength) * denominator;
  ycirca = (xba * calength - xca * balength) * denominator;
  orthocenter[0] = xcirca;
  orthocenter[1] = ycirca;
}


x86 assembly (clang, -O0):
<triorthocenter>:
push   %rbp
mov    %rsp,%rbp
sub    $0x80,%rsp
mov    %rdi,-0x8(%rbp)
mov    %rsi,-0x10(%rbp)
mov    %rdx,-0x18(%rbp)
mov    %rcx,-0x20(%rbp)
mov    %r8,-0x28(%rbp)
mov    -0x10(%rbp),%rax
movsd  (%rax),%xmm0
mov    -0x8(%rbp),%rax
subsd  (%rax),%xmm0
movsd  %xmm0,-0x30(%rbp)
mov    -0x10(%rbp),%rax
movsd  0x8(%rax),%xmm0
mov    -0x8(%rbp),%rax
subsd  0x8(%rax),%xmm0
movsd  %xmm0,-0x38(%rbp)
mov    -0x10(%rbp),%rax
movsd  0x10(%rax),%xmm0
mov    -0x8(%rbp),%rax
subsd  0x10(%rax),%xmm0
movsd  %xmm0,-0x40(%rbp)
mov    -0x18(%rbp),%rax
movsd  (%rax),%xmm0
mov    -0x8(%rbp),%rax
subsd  (%rax),%xmm0
movsd  %xmm0,-0x48(%rbp)
mov    -0x18(%rbp),%rax
movsd  0x8(%rax),%xmm0
mov    -0x8(%rbp),%rax
subsd  0x8(%rax),%xmm0
movsd  %xmm0,-0x50(%rbp)
mov    -0x10(%rbp),%rax
movsd  0x10(%rax),%xmm0
mov    -0x8(%rbp),%rax
subsd  0x10(%rax),%xmm0
movsd  %xmm0,-0x58(%rbp)
movsd  -0x30(%rbp),%xmm0
movsd  -0x30(%rbp),%xmm2
movsd  -0x38(%rbp),%xmm1
mulsd  -0x38(%rbp),%xmm1
mulsd  %xmm2,%xmm0
addsd  %xmm1,%xmm0
subsd  -0x40(%rbp),%xmm0
movsd  %xmm0,-0x60(%rbp)
movsd  -0x48(%rbp),%xmm0
movsd  -0x48(%rbp),%xmm2
movsd  -0x50(%rbp),%xmm1
mulsd  -0x50(%rbp),%xmm1
mulsd  %xmm2,%xmm0
addsd  %xmm1,%xmm0
subsd  -0x58(%rbp),%xmm0
movsd  %xmm0,-0x68(%rbp)
mov    -0x10(%rbp),%rdi
mov    -0x18(%rbp),%rsi
mov    -0x8(%rbp),%rdx
mov    $0x0,%al
call   1030 <orient2d@plt>
cvtsi2sd %eax,%xmm0
mov    -0x28(%rbp),%rax
movsd  %xmm0,(%rax)
mov    -0x28(%rbp),%rax
movsd  0xdd4(%rip),%xmm0
divsd  (%rax),%xmm0
movsd  %xmm0,-0x70(%rbp)
movsd  -0x50(%rbp),%xmm0
movsd  -0x60(%rbp),%xmm2
movsd  -0x38(%rbp),%xmm1
mulsd  -0x68(%rbp),%xmm1
movq   %xmm1,%rax
movabs $0x8000000000000000,%rcx
xor    %rcx,%rax
movq   %rax,%xmm1
mulsd  %xmm2,%xmm0
addsd  %xmm1,%xmm0
mulsd  -0x70(%rbp),%xmm0
movsd  %xmm0,-0x78(%rbp)
movsd  -0x30(%rbp),%xmm0
movsd  -0x68(%rbp),%xmm2
movsd  -0x48(%rbp),%xmm1
mulsd  -0x60(%rbp),%xmm1
movq   %xmm1,%rax
movabs $0x8000000000000000,%rcx
xor    %rcx,%rax
movq   %rax,%xmm1
mulsd  %xmm2,%xmm0
addsd  %xmm1,%xmm0
mulsd  -0x70(%rbp),%xmm0
movsd  %xmm0,-0x80(%rbp)
movsd  -0x78(%rbp),%xmm0
mov    -0x20(%rbp),%rax
movsd  %xmm0,(%rax)
movsd  -0x80(%rbp),%xmm0
mov    -0x20(%rbp),%rax
movsd  %xmm0,0x8(%rax)
add    $0x80,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<triorthocenter>:
push   %r14
push   %rbx
sub    $0x38,%rsp
mov    %r8,%rbx
mov    %rcx,%r14
mov    %rdi,%rax
movupd (%rdi),%xmm0
movsd  0x10(%rsi),%xmm1
subsd  0x10(%rdi),%xmm1
shufpd $0x1,%xmm0,%xmm0
movsd  0x8(%rsi),%xmm3
movhpd (%rdx),%xmm3
subpd  %xmm0,%xmm3
movapd %xmm3,0x20(%rsp)
movsd  0x8(%rdx),%xmm2
movhpd (%rsi),%xmm2
subpd  %xmm0,%xmm2
movapd %xmm2,0x10(%rsp)
movapd %xmm3,%xmm0
unpcklpd %xmm2,%xmm0
mulpd  %xmm0,%xmm0
unpckhpd %xmm3,%xmm2
mulpd  %xmm2,%xmm2
addpd  %xmm0,%xmm2
unpcklpd %xmm1,%xmm1
subpd  %xmm1,%xmm2
movapd %xmm2,(%rsp)
mov    %rsi,%rdi
mov    %rdx,%rsi
mov    %rax,%rdx
xor    %eax,%eax
call   1030 <orient2d@plt>
xorps  %xmm0,%xmm0
cvtsi2sd %eax,%xmm0
movsd  %xmm0,(%rbx)
movsd  0xe5f(%rip),%xmm1
divsd  %xmm0,%xmm1
movapd 0x10(%rsp),%xmm0
movapd (%rsp),%xmm2
mulpd  %xmm2,%xmm0
shufpd $0x1,%xmm2,%xmm2
mulpd  0x20(%rsp),%xmm2
subpd  %xmm2,%xmm0
unpcklpd %xmm1,%xmm1
mulpd  %xmm0,%xmm1
movupd %xmm1,(%r14)
add    $0x38,%rsp
pop    %rbx
pop    %r14
ret

LLVM IR (-O0):
define void @triorthocenter(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
%15 = alloca double
%16 = alloca double
%17 = alloca double
%18 = alloca double
%19 = alloca double
%20 = alloca double
%21 = 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
%22 = load double*, double** %7
%23 = getelementptr inbounds double, double* %22, i64 0
%24 = load double, double* %23
%25 = load double*, double** %6
%26 = getelementptr inbounds double, double* %25, i64 0
%27 = load double, double* %26
%28 = fsub double %24, %27
store double %28, double* %11
%29 = load double*, double** %7
%30 = getelementptr inbounds double, double* %29, i64 1
%31 = load double, double* %30
%32 = load double*, double** %6
%33 = getelementptr inbounds double, double* %32, i64 1
%34 = load double, double* %33
%35 = fsub double %31, %34
store double %35, double* %12
%36 = load double*, double** %7
%37 = getelementptr inbounds double, double* %36, i64 2
%38 = load double, double* %37
%39 = load double*, double** %6
%40 = getelementptr inbounds double, double* %39, i64 2
%41 = load double, double* %40
%42 = fsub double %38, %41
store double %42, double* %13
%43 = load double*, double** %8
%44 = getelementptr inbounds double, double* %43, i64 0
%45 = load double, double* %44
%46 = load double*, double** %6
%47 = getelementptr inbounds double, double* %46, i64 0
%48 = load double, double* %47
%49 = fsub double %45, %48
store double %49, double* %14
%50 = load double*, double** %8
%51 = getelementptr inbounds double, double* %50, i64 1
%52 = load double, double* %51
%53 = load double*, double** %6
%54 = getelementptr inbounds double, double* %53, i64 1
%55 = load double, double* %54
%56 = fsub double %52, %55
store double %56, double* %15
%57 = load double*, double** %7
%58 = getelementptr inbounds double, double* %57, i64 2
%59 = load double, double* %58
%60 = load double*, double** %6
%61 = getelementptr inbounds double, double* %60, i64 2
%62 = load double, double* %61
%63 = fsub double %59, %62
store double %63, double* %16
%64 = load double, double* %11
%65 = load double, double* %11
%66 = load double, double* %12
%67 = load double, double* %12
%68 = fmul double %66, %67
%69 = call double @llvm.fmuladd.f64(double %64, double %65, double %68)
%70 = load double, double* %13
%71 = fsub double %69, %70
store double %71, double* %17
%72 = load double, double* %14
%73 = load double, double* %14
%74 = load double, double* %15
%75 = load double, double* %15
%76 = fmul double %74, %75
%77 = call double @llvm.fmuladd.f64(double %72, double %73, double %76)
%78 = load double, double* %16
%79 = fsub double %77, %78
store double %79, double* %18
%80 = load double*, double** %7
%81 = load double*, double** %8
%82 = load double*, double** %6
%83 = call i32 (double*, double*, double*, ...) bitcast (i32 (...)* @orient2d to i32 (double*, double*, double*, ...)*)(double* %80, double* %81, double* %82)
%84 = sitofp i32 %83 to double
%85 = load double*, double** %10
store double %84, double* %85
%86 = load double*, double** %10
%87 = load double, double* %86
%88 = fdiv double 5.000000e-01, %87
store double %88, double* %19
%89 = load double, double* %15
%90 = load double, double* %17
%91 = load double, double* %12
%92 = load double, double* %18
%93 = fmul double %91, %92
%94 = fneg double %93
%95 = call double @llvm.fmuladd.f64(double %89, double %90, double %94)
%96 = load double, double* %19
%97 = fmul double %95, %96
store double %97, double* %20
%98 = load double, double* %11
%99 = load double, double* %18
%100 = load double, double* %14
%101 = load double, double* %17
%102 = fmul double %100, %101
%103 = fneg double %102
%104 = call double @llvm.fmuladd.f64(double %98, double %99, double %103)
%105 = load double, double* %19
%106 = fmul double %104, %105
store double %106, double* %21
%107 = load double, double* %20
%108 = load double*, double** %9
%109 = getelementptr inbounds double, double* %108, i64 0
store double %107, double* %109
%110 = load double, double* %21
%111 = load double*, double** %9
%112 = getelementptr inbounds double, double* %111, i64 1
store double %110, double* %112
ret void
}

LLVM IR (-O2):
define void @triorthocenter(double* %0, double* %1, double* %2, double* nocapture writeonly %3, double* nocapture writeonly %4) {
%6 = load double, double* %1
%7 = getelementptr inbounds double, double* %1, i64 1
%8 = load double, double* %7
%9 = bitcast double* %0 to <2 x double>*
%10 = load <2 x double>, <2 x double>* %9
%11 = shufflevector <2 x double> %10, <2 x double> poison, <2 x i32> <i32 1, i32 0>
%12 = getelementptr inbounds double, double* %1, i64 2
%13 = load double, double* %12
%14 = getelementptr inbounds double, double* %0, i64 2
%15 = load double, double* %14
%16 = fsub double %13, %15
%17 = load double, double* %2
%18 = insertelement <2 x double> poison, double %8, i64 0
%19 = insertelement <2 x double> %18, double %17, i64 1
%20 = fsub <2 x double> %19, %11
%21 = getelementptr inbounds double, double* %2, i64 1
%22 = load double, double* %21
%23 = insertelement <2 x double> poison, double %22, i64 0
%24 = insertelement <2 x double> %23, double %6, i64 1
%25 = fsub <2 x double> %24, %11
%26 = shufflevector <2 x double> %20, <2 x double> %25, <2 x i32> <i32 0, i32 2>
%27 = fmul <2 x double> %26, %26
%28 = shufflevector <2 x double> %25, <2 x double> %20, <2 x i32> <i32 1, i32 3>
%29 = call <2 x double> @llvm.fmuladd.v2f64(<2 x double> %28, <2 x double> %28, <2 x double> %27)
%30 = insertelement <2 x double> poison, double %16, i64 0
%31 = shufflevector <2 x double> %30, <2 x double> poison, <2 x i32> zeroinitializer
%32 = fsub <2 x double> %29, %31
%33 = tail call i32 (double*, double*, double*, ...) bitcast (i32 (...)* @orient2d to i32 (double*, double*, double*, ...)*)(double* %1, double* %2, double* %0)
%34 = sitofp i32 %33 to double
store double %34, double* %4
%35 = fdiv double 5.000000e-01, %34
%36 = fneg <2 x double> %20
%37 = shufflevector <2 x double> %32, <2 x double> undef, <2 x i32> <i32 1, i32 0>
%38 = fmul <2 x double> %37, %36
%39 = call <2 x double> @llvm.fmuladd.v2f64(<2 x double> %25, <2 x double> %32, <2 x double> %38)
%40 = insertelement <2 x double> poison, double %35, i64 0
%41 = shufflevector <2 x double> %40, <2 x double> poison, <2 x i32> zeroinitializer
%42 = fmul <2 x double> %41, %39
%43 = bitcast double* %3 to <2 x double>*
store <2 x double> %42, <2 x double>* %43
ret void
}