#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);
int /*<<< orphan*/ perror(char *);
int pipe(int *);
int /*<<< orphan*/ printf(char *, ...);
int /*<<< orphan*/ read(int, char *, int);
int /*<<< orphan*/ write(int, char *, int);
int main(void) {
  int pfds[2];
  char buf[30];
  if (pipe(pfds) == -1) {
    perror("pipe");
    exit(1);
  }
  printf("writing to file descriptor #%d\n", pfds[1]);
  write(pfds[1], "test", 5);
  printf("reading from file descriptor #%d\n", pfds[0]);
  read(pfds[0], buf, 5);
  printf("read \"%s\"\n", buf);
  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>
cmp    $0xffffffff,%eax
jne    1197 <main+0x37>
lea    0xe78(%rip),%rdi
call   1070 <perror@plt>
mov    $0x1,%edi
call   1080 <exit@plt>
mov    -0x8(%rbp),%esi
lea    0xe64(%rip),%rdi
mov    $0x0,%al
call   1040 <printf@plt>
mov    -0x8(%rbp),%edi
lea    0xe73(%rip),%rsi
mov    $0x5,%edx
call   1030 <write@plt>
mov    -0xc(%rbp),%esi
lea    0xe64(%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    0xe63(%rip),%rdi
mov    $0x0,%al
call   1040 <printf@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   1050 <pipe@plt>
cmp    $0xffffffff,%eax
je     11dc <main+0x7c>
mov    0xc(%rsp),%esi
lea    0xe86(%rip),%rdi
xor    %eax,%eax
call   1040 <printf@plt>
mov    0xc(%rsp),%edi
lea    0xe94(%rip),%rsi
mov    $0x5,%edx
call   1030 <write@plt>
mov    0x8(%rsp),%esi
lea    0xe84(%rip),%rdi
xor    %eax,%eax
call   1040 <printf@plt>
mov    0x8(%rsp),%edi
lea    0x10(%rsp),%rbx
mov    %rbx,%rsi
mov    $0x5,%edx
call   1060 <read@plt>
lea    0xe82(%rip),%rdi
mov    %rbx,%rsi
xor    %eax,%eax
call   1040 <printf@plt>
xor    %eax,%eax
add    $0x30,%rsp
pop    %rbx
ret
lea    0xe1d(%rip),%rdi
call   1070 <perror@plt>
mov    $0x1,%edi
call   1080 <exit@plt>

LLVM IR (-O0):
@.str = [5 x i8] c"pipe\00"
@.str.1 = [32 x i8] c"writing to file descriptor #%d\0A\00"
@.str.2 = [5 x i8] c"test\00"
@.str.3 = [34 x i8] c"reading from file descriptor #%d\0A\00"
@.str.4 = [11 x i8] c"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 = icmp eq i32 %5, -1
br i1 %6, label %7, label %10
7: ; preds = %0
%8 = call i32 @perror(i8* getelementptr inbounds ([5 x i8], [5 x i8]* @.str, i64 0, i64 0))
%9 = call i32 @exit(i32 1)
unreachable
10: ; preds = %0
%11 = getelementptr inbounds [2 x i32], [2 x i32]* %2, i64 0, i64 1
%12 = load i32, i32* %11
%13 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([32 x i8], [32 x i8]* @.str.1, i64 0, i64 0), i32 %12)
%14 = getelementptr inbounds [2 x i32], [2 x i32]* %2, i64 0, i64 1
%15 = load i32, i32* %14
%16 = call i32 @write(i32 %15, i8* getelementptr inbounds ([5 x i8], [5 x i8]* @.str.2, i64 0, i64 0), i32 5)
%17 = getelementptr inbounds [2 x i32], [2 x i32]* %2, i64 0, i64 0
%18 = load i32, i32* %17
%19 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([34 x i8], [34 x i8]* @.str.3, i64 0, i64 0), i32 %18)
%20 = getelementptr inbounds [2 x i32], [2 x i32]* %2, i64 0, i64 0
%21 = load i32, i32* %20
%22 = getelementptr inbounds [30 x i8], [30 x i8]* %3, i64 0, i64 0
%23 = call i32 @read(i32 %21, i8* %22, i32 5)
%24 = getelementptr inbounds [30 x i8], [30 x i8]* %3, i64 0, i64 0
%25 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([11 x i8], [11 x i8]* @.str.4, i64 0, i64 0), i8* %24)
ret i32 0
}

LLVM IR (-O2):
@.str = [5 x i8] c"pipe\00"
@.str.1 = [32 x i8] c"writing to file descriptor #%d\0A\00"
@.str.2 = [5 x i8] c"test\00"
@.str.3 = [34 x i8] c"reading from file descriptor #%d\0A\00"
@.str.4 = [11 x i8] c"read \22%s\22\0A\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 = icmp eq i32 %6, -1
br i1 %7, label %8, label %11
8: ; preds = %0
%9 = call i32 @perror(i8* getelementptr inbounds ([5 x i8], [5 x i8]* @.str, i64 0, i64 0))
%10 = call i32 @exit(i32 1)
unreachable
11: ; preds = %0
%12 = getelementptr inbounds [2 x i32], [2 x i32]* %1, i64 0, i64 1
%13 = load i32, i32* %12
%14 = call i32 (i8*, ...) @printf(i8* dereferenceable(1) getelementptr inbounds ([32 x i8], [32 x i8]* @.str.1, i64 0, i64 0), i32 %13)
%15 = load i32, i32* %12
%16 = call i32 @write(i32 %15, i8* getelementptr inbounds ([5 x i8], [5 x i8]* @.str.2, i64 0, i64 0), i32 5)
%17 = load i32, i32* %5
%18 = call i32 (i8*, ...) @printf(i8* dereferenceable(1) getelementptr inbounds ([34 x i8], [34 x i8]* @.str.3, i64 0, i64 0), i32 %17)
%19 = load i32, i32* %5
%20 = call i32 @read(i32 %19, i8* %4, i32 5)
%21 = call i32 (i8*, ...) @printf(i8* dereferenceable(1) getelementptr inbounds ([11 x i8], [11 x i8]* @.str.4, i64 0, i64 0), i8* %4)
ret i32 0
}