#define NULL ((void *)0)
typedef unsigned long size_t; // Customize by platform.
typedef long intptr_t;
typedef unsigned long uintptr_t;
typedef long scalar_t__; // Either arithmetic or pointer type.
/* By default, we understand bool (as a convenience). */
typedef int bool;
#define false 0
#define true 1

/* Forward declarations */

/* Type definitions */

/* Variables and functions */
double sqrt(double);
double *calc_unit(double *v) {
  double total;
  total = sqrt(v[0] * v[0] + v[1] * v[1] + v[2] * v[2]);
  if (total) {
    v[0] /= total;
    v[1] /= total;
    v[2] /= total;
  }
  return (v);
}


x86 assembly (clang, -O0):
<calc_unit>:
push   %rbp
mov    %rsp,%rbp
sub    $0x10,%rsp
mov    %rdi,-0x8(%rbp)
mov    -0x8(%rbp),%rax
movsd  (%rax),%xmm1
mov    -0x8(%rbp),%rax
movsd  (%rax),%xmm2
mov    -0x8(%rbp),%rax
movsd  0x8(%rax),%xmm0
mov    -0x8(%rbp),%rax
mulsd  0x8(%rax),%xmm0
mulsd  %xmm2,%xmm1
addsd  %xmm0,%xmm1
mov    -0x8(%rbp),%rax
movsd  0x10(%rax),%xmm0
mov    -0x8(%rbp),%rax
movsd  0x10(%rax),%xmm2
mulsd  %xmm2,%xmm0
addsd  %xmm1,%xmm0
call   1030 <sqrt@plt>
movsd  %xmm0,-0x10(%rbp)
movsd  -0x10(%rbp),%xmm0
xorps  %xmm1,%xmm1
ucomisd %xmm1,%xmm0
jne    1187 <calc_unit+0x77>
jp     1187 <calc_unit+0x77>
jmp    11ca <calc_unit+0xba>
movsd  -0x10(%rbp),%xmm1
mov    -0x8(%rbp),%rax
movsd  (%rax),%xmm0
divsd  %xmm1,%xmm0
movsd  %xmm0,(%rax)
movsd  -0x10(%rbp),%xmm1
mov    -0x8(%rbp),%rax
movsd  0x8(%rax),%xmm0
divsd  %xmm1,%xmm0
movsd  %xmm0,0x8(%rax)
movsd  -0x10(%rbp),%xmm1
mov    -0x8(%rbp),%rax
movsd  0x10(%rax),%xmm0
divsd  %xmm1,%xmm0
movsd  %xmm0,0x10(%rax)
mov    -0x8(%rbp),%rax
add    $0x10,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<calc_unit>:
push   %rbx
mov    %rdi,%rbx
movsd  (%rdi),%xmm1
movsd  0x8(%rdi),%xmm0
mulsd  %xmm0,%xmm0
mulsd  %xmm1,%xmm1
addsd  %xmm0,%xmm1
movsd  0x10(%rdi),%xmm0
mulsd  %xmm0,%xmm0
addsd  %xmm1,%xmm0
xorpd  %xmm1,%xmm1
ucomisd %xmm1,%xmm0
jb     1146 <calc_unit+0x36>
sqrtsd %xmm0,%xmm0
jmp    114f <calc_unit+0x3f>
call   1030 <sqrt@plt>
xorpd  %xmm1,%xmm1
ucomisd %xmm1,%xmm0
jne    1157 <calc_unit+0x47>
jnp    1179 <calc_unit+0x69>
movupd (%rbx),%xmm1
movapd %xmm0,%xmm2
unpcklpd %xmm0,%xmm2
divpd  %xmm2,%xmm1
movupd %xmm1,(%rbx)
movsd  0x10(%rbx),%xmm1
divsd  %xmm0,%xmm1
movsd  %xmm1,0x10(%rbx)
mov    %rbx,%rax
pop    %rbx
ret

LLVM IR (-O0):
define double* @calc_unit(double* %0) {
%2 = alloca double*
%3 = alloca double
store double* %0, double** %2
%4 = load double*, double** %2
%5 = getelementptr inbounds double, double* %4, i64 0
%6 = load double, double* %5
%7 = load double*, double** %2
%8 = getelementptr inbounds double, double* %7, i64 0
%9 = load double, double* %8
%10 = load double*, double** %2
%11 = getelementptr inbounds double, double* %10, i64 1
%12 = load double, double* %11
%13 = load double*, double** %2
%14 = getelementptr inbounds double, double* %13, i64 1
%15 = load double, double* %14
%16 = fmul double %12, %15
%17 = call double @llvm.fmuladd.f64(double %6, double %9, double %16)
%18 = load double*, double** %2
%19 = getelementptr inbounds double, double* %18, i64 2
%20 = load double, double* %19
%21 = load double*, double** %2
%22 = getelementptr inbounds double, double* %21, i64 2
%23 = load double, double* %22
%24 = call double @llvm.fmuladd.f64(double %20, double %23, double %17)
%25 = call double @sqrt(double %24)
store double %25, double* %3
%26 = load double, double* %3
%27 = fcmp une double %26, 0.000000e+00
br i1 %27, label %28, label %44
28: ; preds = %1
%29 = load double, double* %3
%30 = load double*, double** %2
%31 = getelementptr inbounds double, double* %30, i64 0
%32 = load double, double* %31
%33 = fdiv double %32, %29
store double %33, double* %31
%34 = load double, double* %3
%35 = load double*, double** %2
%36 = getelementptr inbounds double, double* %35, i64 1
%37 = load double, double* %36
%38 = fdiv double %37, %34
store double %38, double* %36
%39 = load double, double* %3
%40 = load double*, double** %2
%41 = getelementptr inbounds double, double* %40, i64 2
%42 = load double, double* %41
%43 = fdiv double %42, %39
store double %43, double* %41
br label %44
44: ; preds = %28, %1
%45 = load double*, double** %2
ret double* %45
}

LLVM IR (-O2):
define double* @calc_unit(double* returned %0) {
%2 = load double, double* %0
%3 = getelementptr inbounds double, double* %0, i64 1
%4 = load double, double* %3
%5 = fmul double %4, %4
%6 = tail call double @llvm.fmuladd.f64(double %2, double %2, double %5)
%7 = getelementptr inbounds double, double* %0, i64 2
%8 = load double, double* %7
%9 = tail call double @llvm.fmuladd.f64(double %8, double %8, double %6)
%10 = tail call double @sqrt(double %9)
%11 = fcmp une double %10, 0.000000e+00
br i1 %11, label %12, label %21
12: ; preds = %1
%13 = bitcast double* %0 to <2 x double>*
%14 = load <2 x double>, <2 x double>* %13
%15 = insertelement <2 x double> poison, double %10, i64 0
%16 = shufflevector <2 x double> %15, <2 x double> poison, <2 x i32> zeroinitializer
%17 = fdiv <2 x double> %14, %16
%18 = bitcast double* %0 to <2 x double>*
store <2 x double> %17, <2 x double>* %18
%19 = load double, double* %7
%20 = fdiv double %19, %10
store double %20, double* %7
br label %21
21: ; preds = %12, %1
ret double* %0
}