#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 */
int /*<<< orphan*/ exit(int /*<<< orphan*/);
int /*<<< orphan*/ fork();
int /*<<< orphan*/ pipe(int *);
int /*<<< orphan*/ printf(char *, ...);
int /*<<< orphan*/ read(int, char *, int);
int /*<<< orphan*/ wait(int /*<<< orphan*/ *);
int /*<<< orphan*/ write(int, char *, int);
int main(void) {
  int pfds[2];
  char buf[30];
  pipe(pfds);
  if (!fork()) {
    printf(" CHILD: writing to the pipe\n");
    write(pfds[1], "test", 5);
    printf(" CHILD: exiting\n");
    exit(0);
  } else {
    printf("PARENT: reading from pipe\n");
    read(pfds[0], buf, 5);
    printf("PARENT: read \"%s\"\n", buf);
    wait(NULL);
  }
  return 0;
}


x86 assembly (clang, -O0):
<main>:
push   %rbp
mov    %rsp,%rbp
sub    $0x30,%rsp
movl   $0x0,-0x4(%rbp)
lea    -0xc(%rbp),%rdi
call   1050 <pipe@plt>
mov    $0x0,%al
call   1090 <fork@plt>
cmp    $0x0,%eax
jne    11cf <main+0x5f>
lea    0xe61(%rip),%rdi
mov    $0x0,%al
call   1040 <printf@plt>
mov    -0x8(%rbp),%edi
lea    0xe6d(%rip),%rsi
mov    $0x5,%edx
call   1030 <write@plt>
lea    0xe61(%rip),%rdi
mov    $0x0,%al
call   1040 <printf@plt>
xor    %edi,%edi
call   1070 <exit@plt>
lea    0xe5d(%rip),%rdi
mov    $0x0,%al
call   1040 <printf@plt>
mov    -0xc(%rbp),%edi
lea    -0x30(%rbp),%rsi
mov    $0x5,%edx
call   1060 <read@plt>
lea    -0x30(%rbp),%rsi
lea    0xe55(%rip),%rdi
mov    $0x0,%al
call   1040 <printf@plt>
xor    %eax,%eax
mov    %eax,%edi
call   1080 <wait@plt>
xor    %eax,%eax
add    $0x30,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<main>:
push   %rbx
sub    $0x30,%rsp
lea    0x8(%rsp),%rdi
call   1060 <pipe@plt>
xor    %eax,%eax
call   10a0 <fork@plt>
test   %eax,%eax
je     11dc <main+0x5c>
lea    0xea3(%rip),%rdi
call   1030 <puts@plt>
mov    0x8(%rsp),%edi
lea    0x10(%rsp),%rbx
mov    %rbx,%rsi
mov    $0x5,%edx
call   1070 <read@plt>
lea    0xe42(%rip),%rdi
mov    %rbx,%rsi
xor    %eax,%eax
call   1050 <printf@plt>
xor    %edi,%edi
call   1090 <wait@plt>
xor    %eax,%eax
add    $0x30,%rsp
pop    %rbx
ret
lea    0xe35(%rip),%rdi
call   1030 <puts@plt>
mov    0xc(%rsp),%edi
lea    0xe0d(%rip),%rsi
mov    $0x5,%edx
call   1040 <write@plt>
lea    0xe30(%rip),%rdi
call   1030 <puts@plt>
xor    %edi,%edi
call   1080 <exit@plt>

LLVM IR (-O0):
@.str = [29 x i8] c" CHILD: writing to the pipe\0A\00"
@.str.1 = [5 x i8] c"test\00"
@.str.2 = [17 x i8] c" CHILD: exiting\0A\00"
@.str.3 = [27 x i8] c"PARENT: reading from pipe\0A\00"
@.str.4 = [19 x i8] c"PARENT: read \22%s\22\0A\00"
define i32 @main() {
%1 = alloca i32
%2 = alloca [2 x i32]
%3 = alloca [30 x i8]
store i32 0, i32* %1
%4 = getelementptr inbounds [2 x i32], [2 x i32]* %2, i64 0, i64 0
%5 = call i32 @pipe(i32* %4)
%6 = call i32 (...) @fork()
%7 = icmp ne i32 %6, 0
br i1 %7, label %15, label %8
8: ; preds = %0
%9 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([29 x i8], [29 x i8]* @.str, i64 0, i64 0))
%10 = getelementptr inbounds [2 x i32], [2 x i32]* %2, i64 0, i64 1
%11 = load i32, i32* %10
%12 = call i32 @write(i32 %11, i8* getelementptr inbounds ([5 x i8], [5 x i8]* @.str.1, i64 0, i64 0), i32 5)
%13 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([17 x i8], [17 x i8]* @.str.2, i64 0, i64 0))
%14 = call i32 @exit(i32 0)
unreachable
15: ; preds = %0
%16 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([27 x i8], [27 x i8]* @.str.3, i64 0, i64 0))
%17 = getelementptr inbounds [2 x i32], [2 x i32]* %2, i64 0, i64 0
%18 = load i32, i32* %17
%19 = getelementptr inbounds [30 x i8], [30 x i8]* %3, i64 0, i64 0
%20 = call i32 @read(i32 %18, i8* %19, i32 5)
%21 = getelementptr inbounds [30 x i8], [30 x i8]* %3, i64 0, i64 0
%22 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([19 x i8], [19 x i8]* @.str.4, i64 0, i64 0), i8* %21)
%23 = call i32 @wait(i32* null)
br label %24
24: ; preds = %15
ret i32 0
}

LLVM IR (-O2):
@.str.1 = [5 x i8] c"test\00"
@.str.4 = [19 x i8] c"PARENT: read \22%s\22\0A\00"
@str = [28 x i8] c" CHILD: writing to the pipe\00"
@str.5 = [16 x i8] c" CHILD: exiting\00"
@str.6 = [26 x i8] c"PARENT: reading from pipe\00"
define i32 @main() {
%1 = alloca [2 x i32]
%2 = alloca [30 x i8]
%3 = bitcast [2 x i32]* %1 to i8*
%4 = getelementptr inbounds [30 x i8], [30 x i8]* %2, i64 0, i64 0
%5 = getelementptr inbounds [2 x i32], [2 x i32]* %1, i64 0, i64 0
%6 = call i32 @pipe(i32* %5)
%7 = call i32 (...) @fork()
%8 = icmp eq i32 %7, 0
br i1 %8, label %9, label %16
9: ; preds = %0
%10 = call i32 @puts(i8* dereferenceable(1) getelementptr inbounds ([28 x i8], [28 x i8]* @str, i64 0, i64 0))
%11 = getelementptr inbounds [2 x i32], [2 x i32]* %1, i64 0, i64 1
%12 = load i32, i32* %11
%13 = call i32 @write(i32 %12, i8* getelementptr inbounds ([5 x i8], [5 x i8]* @.str.1, i64 0, i64 0), i32 5)
%14 = call i32 @puts(i8* dereferenceable(1) getelementptr inbounds ([16 x i8], [16 x i8]* @str.5, i64 0, i64 0))
%15 = call i32 @exit(i32 0)
unreachable
16: ; preds = %0
%17 = call i32 @puts(i8* dereferenceable(1) getelementptr inbounds ([26 x i8], [26 x i8]* @str.6, i64 0, i64 0))
%18 = load i32, i32* %5
%19 = call i32 @read(i32 %18, i8* %4, i32 5)
%20 = call i32 (i8*, ...) @printf(i8* dereferenceable(1) getelementptr inbounds ([19 x i8], [19 x i8]* @.str.4, i64 0, i64 0), i8* %4)
%21 = call i32 @wait(i32* null)
ret i32 0
}