#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 */
scalar_t__ fork();
int getpid();
int getppid();
int /*<<< orphan*/ printf(char *, ...);
int /*<<< orphan*/ scanf(char *, int *);
int main() {
  int n, mypid, parpid;
  printf("Parent: n = ");
  scanf("%d", &n);
  if (fork()) {
    mypid = getpid();
    parpid = getppid();
    printf("Parent: PID = %u, PPID = %u...\n", mypid, parpid);
  } else {
    mypid = getpid();
    parpid = getppid();
    printf("Child : PID = %u, PPID = %u...\n", mypid, parpid);
    n = n * n;
  }
  printf("Process PID = %u: n = %d\n", mypid, n);
  return 0;
}


x86 assembly (clang, -O0):
<main>:
push   %rbp
mov    %rsp,%rbp
sub    $0x10,%rsp
movl   $0x0,-0x4(%rbp)
lea    0xe9a(%rip),%rdi
mov    $0x0,%al
call   1040 <printf@plt>
lea    0xe99(%rip),%rdi
lea    -0x8(%rbp),%rsi
call   1050 <scanf@plt>
mov    $0x0,%al
call   1070 <fork@plt>
cmp    $0x0,%rax
je     11bb <main+0x6b>
mov    $0x0,%al
call   1030 <getpid@plt>
mov    %eax,-0xc(%rbp)
mov    $0x0,%al
call   1060 <getppid@plt>
mov    %eax,-0x10(%rbp)
mov    -0xc(%rbp),%esi
mov    -0x10(%rbp),%edx
lea    0xe61(%rip),%rdi
mov    $0x0,%al
call   1040 <printf@plt>
jmp    11ed <main+0x9d>
mov    $0x0,%al
call   1030 <getpid@plt>
mov    %eax,-0xc(%rbp)
mov    $0x0,%al
call   1060 <getppid@plt>
mov    %eax,-0x10(%rbp)
mov    -0xc(%rbp),%esi
mov    -0x10(%rbp),%edx
lea    0xe54(%rip),%rdi
mov    $0x0,%al
call   1040 <printf@plt>
mov    -0x8(%rbp),%eax
imul   -0x8(%rbp),%eax
mov    %eax,-0x8(%rbp)
mov    -0xc(%rbp),%esi
mov    -0x8(%rbp),%edx
lea    0xe56(%rip),%rdi
mov    $0x0,%al
call   1040 <printf@plt>
xor    %eax,%eax
add    $0x10,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<main>:
push   %rbp
push   %rbx
push   %rax
lea    0xea6(%rip),%rdi
xor    %eax,%eax
call   1040 <printf@plt>
lea    0xea5(%rip),%rdi
lea    0x4(%rsp),%rsi
call   1050 <scanf@plt>
xor    %eax,%eax
call   1070 <fork@plt>
mov    %rax,%rbx
xor    %eax,%eax
call   1030 <getpid@plt>
mov    %eax,%ebp
xor    %eax,%eax
call   1060 <getppid@plt>
test   %rbx,%rbx
je     11a9 <main+0x59>
lea    0xe78(%rip),%rdi
mov    %ebp,%esi
mov    %eax,%edx
xor    %eax,%eax
call   1040 <printf@plt>
mov    0x4(%rsp),%edx
jmp    11c6 <main+0x76>
lea    0xe80(%rip),%rdi
mov    %ebp,%esi
mov    %eax,%edx
xor    %eax,%eax
call   1040 <printf@plt>
mov    0x4(%rsp),%edx
imul   %edx,%edx
mov    %edx,0x4(%rsp)
lea    0xe83(%rip),%rdi
mov    %ebp,%esi
xor    %eax,%eax
call   1040 <printf@plt>
xor    %eax,%eax
add    $0x8,%rsp
pop    %rbx
pop    %rbp
ret

LLVM IR (-O0):
@.str = [13 x i8] c"Parent: n = \00"
@.str.1 = [3 x i8] c"%d\00"
@.str.2 = [32 x i8] c"Parent: PID = %u, PPID = %u...\0A\00"
@.str.3 = [32 x i8] c"Child : PID = %u, PPID = %u...\0A\00"
@.str.4 = [26 x i8] c"Process PID = %u: n = %d\0A\00"
define i32 @main() {
%1 = alloca i32
%2 = alloca i32
%3 = alloca i32
%4 = alloca i32
store i32 0, i32* %1
%5 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([13 x i8], [13 x i8]* @.str, i64 0, i64 0))
%6 = call i32 @scanf(i8* getelementptr inbounds ([3 x i8], [3 x i8]* @.str.1, i64 0, i64 0), i32* %2)
%7 = call i64 (...) @fork()
%8 = icmp ne i64 %7, 0
br i1 %8, label %9, label %15
9: ; preds = %0
%10 = call i32 (...) @getpid()
store i32 %10, i32* %3
%11 = call i32 (...) @getppid()
store i32 %11, i32* %4
%12 = load i32, i32* %3
%13 = load i32, i32* %4
%14 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([32 x i8], [32 x i8]* @.str.2, i64 0, i64 0), i32 %12, i32 %13)
br label %24
15: ; preds = %0
%16 = call i32 (...) @getpid()
store i32 %16, i32* %3
%17 = call i32 (...) @getppid()
store i32 %17, i32* %4
%18 = load i32, i32* %3
%19 = load i32, i32* %4
%20 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([32 x i8], [32 x i8]* @.str.3, i64 0, i64 0), i32 %18, i32 %19)
%21 = load i32, i32* %2
%22 = load i32, i32* %2
%23 = mul nsw i32 %21, %22
store i32 %23, i32* %2
br label %24
24: ; preds = %15, %9
%25 = load i32, i32* %3
%26 = load i32, i32* %2
%27 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([26 x i8], [26 x i8]* @.str.4, i64 0, i64 0), i32 %25, i32 %26)
ret i32 0
}

LLVM IR (-O2):
@.str = [13 x i8] c"Parent: n = \00"
@.str.1 = [3 x i8] c"%d\00"
@.str.2 = [32 x i8] c"Parent: PID = %u, PPID = %u...\0A\00"
@.str.3 = [32 x i8] c"Child : PID = %u, PPID = %u...\0A\00"
@.str.4 = [26 x i8] c"Process PID = %u: n = %d\0A\00"
define i32 @main() {
%1 = alloca i32
%2 = bitcast i32* %1 to i8*
%3 = tail call i32 (i8*, ...) @printf(i8* dereferenceable(1) getelementptr inbounds ([13 x i8], [13 x i8]* @.str, i64 0, i64 0))
%4 = call i32 @scanf(i8* getelementptr inbounds ([3 x i8], [3 x i8]* @.str.1, i64 0, i64 0), i32* %1)
%5 = call i64 (...) @fork()
%6 = icmp eq i64 %5, 0
%7 = call i32 (...) @getpid()
%8 = call i32 (...) @getppid()
br i1 %6, label %12, label %9
9: ; preds = %0
%10 = call i32 (i8*, ...) @printf(i8* dereferenceable(1) getelementptr inbounds ([32 x i8], [32 x i8]* @.str.2, i64 0, i64 0), i32 %7, i32 %8)
%11 = load i32, i32* %1
br label %16
12: ; preds = %0
%13 = call i32 (i8*, ...) @printf(i8* dereferenceable(1) getelementptr inbounds ([32 x i8], [32 x i8]* @.str.3, i64 0, i64 0), i32 %7, i32 %8)
%14 = load i32, i32* %1
%15 = mul nsw i32 %14, %14
store i32 %15, i32* %1
br label %16
16: ; preds = %12, %9
%17 = phi i32 [ %11, %9 ], [ %15, %12 ]
%18 = call i32 (i8*, ...) @printf(i8* dereferenceable(1) getelementptr inbounds ([26 x i8], [26 x i8]* @.str.4, i64 0, i64 0), i32 %7, i32 %17)
ret i32 0
}