#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 */
typedef scalar_t__ pid_t;

/* Variables and functions */
int /*<<< orphan*/ charatatime(char *);
int /*<<< orphan*/ exit(int);
scalar_t__ fork();
int /*<<< orphan*/ fprintf(int /*<<< orphan*/, char *);
int /*<<< orphan*/ stderr;
int main(int argc, char const *argv[]) {
  pid_t pid;
  if ((pid = fork()) < 0) {
    fprintf(stderr, "fork error\n");
    exit(1);
  } else if (pid == 0) {
    charatatime("output from child\n");
  } else {
    charatatime("output from parent\n");
  }
  return 0;
}


x86 assembly (clang, -O0):
<main>:
push   %rbp
mov    %rsp,%rbp
sub    $0x20,%rsp
movl   $0x0,-0x4(%rbp)
mov    %edi,-0x8(%rbp)
mov    %rsi,-0x10(%rbp)
mov    $0x0,%al
call   1060 <fork@plt>
mov    %rax,-0x18(%rbp)
cmp    $0x0,%rax
jge    118a <main+0x4a>
mov    0x2e6e(%rip),%rax
mov    (%rax),%edi
lea    0xe85(%rip),%rsi
call   1040 <fprintf@plt>
mov    $0x1,%edi
call   1050 <exit@plt>
cmpq   $0x0,-0x18(%rbp)
jne    11a6 <main+0x66>
lea    0xe70(%rip),%rdi
call   1030 <charatatime@plt>
jmp    11b2 <main+0x72>
lea    0xe72(%rip),%rdi
call   1030 <charatatime@plt>
jmp    11b7 <main+0x77>
xor    %eax,%eax
add    $0x20,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<main>:
push   %rax
xor    %eax,%eax
call   1060 <fork@plt>
test   %rax,%rax
js     1168 <main+0x28>
lea    0xeb8(%rip),%rax
lea    0xec4(%rip),%rdi
cmove  %rax,%rdi
call   1030 <charatatime@plt>
xor    %eax,%eax
pop    %rcx
ret
mov    0x2e71(%rip),%rax
mov    (%rax),%edi
lea    0xe88(%rip),%rsi
call   1040 <fprintf@plt>
mov    $0x1,%edi
call   1050 <exit@plt>

LLVM IR (-O0):
@stderr = global i32 0
@.str = [12 x i8] c"fork error\0A\00"
@.str.1 = [19 x i8] c"output from child\0A\00"
@.str.2 = [20 x i8] c"output from parent\0A\00"
define i32 @main(i32 %0, i8** %1) {
%3 = alloca i32
%4 = alloca i32
%5 = alloca i8**
%6 = alloca i64
store i32 0, i32* %3
store i32 %0, i32* %4
store i8** %1, i8*** %5
%7 = call i64 (...) @fork()
store i64 %7, i64* %6
%8 = icmp slt i64 %7, 0
br i1 %8, label %9, label %13
9: ; preds = %2
%10 = load i32, i32* @stderr
%11 = call i32 @fprintf(i32 %10, i8* getelementptr inbounds ([12 x i8], [12 x i8]* @.str, i64 0, i64 0))
%12 = call i32 @exit(i32 1)
unreachable
13: ; preds = %2
%14 = load i64, i64* %6
%15 = icmp eq i64 %14, 0
br i1 %15, label %16, label %18
16: ; preds = %13
%17 = call i32 @charatatime(i8* getelementptr inbounds ([19 x i8], [19 x i8]* @.str.1, i64 0, i64 0))
br label %20
18: ; preds = %13
%19 = call i32 @charatatime(i8* getelementptr inbounds ([20 x i8], [20 x i8]* @.str.2, i64 0, i64 0))
br label %20
20: ; preds = %18, %16
br label %21
21: ; preds = %20
ret i32 0
}

LLVM IR (-O2):
@stderr = global i32 0
@.str = [12 x i8] c"fork error\0A\00"
@.str.1 = [19 x i8] c"output from child\0A\00"
@.str.2 = [20 x i8] c"output from parent\0A\00"
define i32 @main(i32 %0, i8** nocapture readnone %1) {
%3 = tail call i64 (...) @fork()
%4 = icmp slt i64 %3, 0
br i1 %4, label %5, label %9
5: ; preds = %2
%6 = load i32, i32* @stderr
%7 = tail call i32 @fprintf(i32 %6, i8* getelementptr inbounds ([12 x i8], [12 x i8]* @.str, i64 0, i64 0))
%8 = tail call i32 @exit(i32 1)
unreachable
9: ; preds = %2
%10 = icmp eq i64 %3, 0
%11 = select i1 %10, i8* getelementptr inbounds ([19 x i8], [19 x i8]* @.str.1, i64 0, i64 0), i8* getelementptr inbounds ([20 x i8], [20 x i8]* @.str.2, i64 0, i64 0)
%12 = tail call i32 @charatatime(i8* %11)
ret i32 0
}