#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 */
typedef struct TYPE_2__ TYPE_1__;

/* Type definitions */
struct TYPE_2__ {
  int /*<<< orphan*/ s_addr;
};
struct sockaddr_in {
  TYPE_1__ sin_addr;
  int /*<<< orphan*/ sin_port;
  int /*<<< orphan*/ sin_family;
};
struct sockaddr {
  int dummy;
};
typedef int /*<<< orphan*/ sa;

/* Variables and functions */
int /*<<< orphan*/ AF_INET;
int /*<<< orphan*/ INADDR_ANY;
int /*<<< orphan*/ SOCK_DGRAM;
int bind(int, struct sockaddr *, int);
int /*<<< orphan*/ bzero(struct sockaddr_in *, int);
int /*<<< orphan*/ err(int /*<<< orphan*/, char *);
int /*<<< orphan*/ errno;
int /*<<< orphan*/ htons(int);
int socket(int /*<<< orphan*/, int /*<<< orphan*/, int /*<<< orphan*/);
int listen_udp_port(int port) {
  int s;
  struct sockaddr_in sa;
  if ((s = socket(AF_INET, SOCK_DGRAM, 0)) == -1)
    err(errno, "socket");
  bzero(&sa, sizeof(sa));
  sa.sin_family = AF_INET;
  sa.sin_port = htons(port);
  sa.sin_addr.s_addr = INADDR_ANY;
  ;
  if (bind(s, (struct sockaddr *)&sa, sizeof(sa)) == -1)
    err(errno, "bind");
  return s;
}


x86 assembly (clang, -O0):
<listen_udp_port>:
push   %rbp
mov    %rsp,%rbp
sub    $0x20,%rsp
mov    %edi,-0x4(%rbp)
mov    0x2e86(%rip),%rax
mov    (%rax),%edi
mov    0x2e6d(%rip),%rax
mov    (%rax),%esi
xor    %edx,%edx
call   1070 <socket@plt>
mov    %eax,-0x8(%rbp)
cmp    $0xffffffff,%eax
jne    1195 <listen_udp_port+0x45>
mov    0x2e41(%rip),%rax
mov    (%rax),%edi
lea    0xe70(%rip),%rsi
call   1040 <err@plt>
lea    -0x18(%rbp),%rdi
mov    $0xc,%esi
call   1060 <bzero@plt>
mov    0x2e3e(%rip),%rax
mov    (%rax),%eax
mov    %eax,-0x10(%rbp)
mov    -0x4(%rbp),%edi
call   1030 <htons@plt>
mov    %eax,-0x14(%rbp)
mov    0x2e1f(%rip),%rax
mov    (%rax),%eax
mov    %eax,-0x18(%rbp)
mov    -0x8(%rbp),%edi
lea    -0x18(%rbp),%rsi
mov    $0xc,%edx
call   1050 <bind@plt>
cmp    $0xffffffff,%eax
jne    11f5 <listen_udp_port+0xa5>
mov    0x2de1(%rip),%rax
mov    (%rax),%edi
lea    0xe17(%rip),%rsi
call   1040 <err@plt>
mov    -0x8(%rbp),%eax
add    $0x20,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<listen_udp_port>:
push   %rbp
push   %r15
push   %r14
push   %rbx
sub    $0x18,%rsp
mov    %edi,%r14d
mov    0x2e84(%rip),%r15
mov    (%r15),%edi
mov    0x2e6a(%rip),%rax
mov    (%rax),%esi
xor    %edx,%edx
call   1070 <socket@plt>
mov    %eax,%ebx
cmp    $0xffffffff,%eax
jne    1193 <listen_udp_port+0x43>
mov    0x2e43(%rip),%rax
mov    (%rax),%edi
lea    0xe72(%rip),%rsi
call   1040 <err@plt>
lea    0x8(%rsp),%rbp
mov    %rbp,%rdi
mov    $0xc,%esi
call   1060 <bzero@plt>
mov    (%r15),%eax
mov    %eax,0x10(%rsp)
mov    %r14d,%edi
call   1030 <htons@plt>
mov    %eax,0xc(%rsp)
mov    0x2e21(%rip),%rax
mov    (%rax),%eax
mov    %eax,0x8(%rsp)
mov    %ebx,%edi
mov    %rbp,%rsi
mov    $0xc,%edx
call   1050 <bind@plt>
cmp    $0xffffffff,%eax
jne    11ee <listen_udp_port+0x9e>
mov    0x2de8(%rip),%rax
mov    (%rax),%edi
lea    0xe1e(%rip),%rsi
call   1040 <err@plt>
mov    %ebx,%eax
add    $0x18,%rsp
pop    %rbx
pop    %r14
pop    %r15
pop    %rbp
ret

LLVM IR (-O0):
%struct.sockaddr_in = type { %struct.TYPE_2__, i32, i32 }
%struct.TYPE_2__ = type { i32 }
%struct.sockaddr = type { i32 }
@AF_INET = global i32 0
@SOCK_DGRAM = global i32 0
@errno = global i32 0
@.str = [7 x i8] c"socket\00"
@INADDR_ANY = global i32 0
@.str.1 = [5 x i8] c"bind\00"
define i32 @listen_udp_port(i32 %0) {
%2 = alloca i32
%3 = alloca i32
%4 = alloca %struct.sockaddr_in
store i32 %0, i32* %2
%5 = load i32, i32* @AF_INET
%6 = load i32, i32* @SOCK_DGRAM
%7 = call i32 @socket(i32 %5, i32 %6, i32 0)
store i32 %7, i32* %3
%8 = icmp eq i32 %7, -1
br i1 %8, label %9, label %12
9: ; preds = %1
%10 = load i32, i32* @errno
%11 = call i32 @err(i32 %10, i8* getelementptr inbounds ([7 x i8], [7 x i8]* @.str, i64 0, i64 0))
br label %12
12: ; preds = %9, %1
%13 = call i32 @bzero(%struct.sockaddr_in* %4, i32 12)
%14 = load i32, i32* @AF_INET
%15 = getelementptr inbounds %struct.sockaddr_in, %struct.sockaddr_in* %4, i32 0, i32 2
store i32 %14, i32* %15
%16 = load i32, i32* %2
%17 = call i32 @htons(i32 %16)
%18 = getelementptr inbounds %struct.sockaddr_in, %struct.sockaddr_in* %4, i32 0, i32 1
store i32 %17, i32* %18
%19 = load i32, i32* @INADDR_ANY
%20 = getelementptr inbounds %struct.sockaddr_in, %struct.sockaddr_in* %4, i32 0, i32 0
%21 = getelementptr inbounds %struct.TYPE_2__, %struct.TYPE_2__* %20, i32 0, i32 0
store i32 %19, i32* %21
%22 = load i32, i32* %3
%23 = bitcast %struct.sockaddr_in* %4 to %struct.sockaddr*
%24 = call i32 @bind(i32 %22, %struct.sockaddr* %23, i32 12)
%25 = icmp eq i32 %24, -1
br i1 %25, label %26, label %29
26: ; preds = %12
%27 = load i32, i32* @errno
%28 = call i32 @err(i32 %27, i8* getelementptr inbounds ([5 x i8], [5 x i8]* @.str.1, i64 0, i64 0))
br label %29
29: ; preds = %26, %12
%30 = load i32, i32* %3
ret i32 %30
}

LLVM IR (-O2):
%struct.sockaddr_in = type { %struct.TYPE_2__, i32, i32 }
%struct.TYPE_2__ = type { i32 }
%struct.sockaddr = type { i32 }
@AF_INET = global i32 0
@SOCK_DGRAM = global i32 0
@errno = global i32 0
@.str = [7 x i8] c"socket\00"
@INADDR_ANY = global i32 0
@.str.1 = [5 x i8] c"bind\00"
define i32 @listen_udp_port(i32 %0) {
%2 = alloca %struct.sockaddr_in
%3 = bitcast %struct.sockaddr_in* %2 to i8*
%4 = load i32, i32* @AF_INET
%5 = load i32, i32* @SOCK_DGRAM
%6 = tail call i32 @socket(i32 %4, i32 %5, i32 0)
%7 = icmp eq i32 %6, -1
br i1 %7, label %8, label %11
8: ; preds = %1
%9 = load i32, i32* @errno
%10 = tail call i32 @err(i32 %9, i8* getelementptr inbounds ([7 x i8], [7 x i8]* @.str, i64 0, i64 0))
br label %11
11: ; preds = %8, %1
%12 = call i32 @bzero(%struct.sockaddr_in* %2, i32 12)
%13 = load i32, i32* @AF_INET
%14 = getelementptr inbounds %struct.sockaddr_in, %struct.sockaddr_in* %2, i64 0, i32 2
store i32 %13, i32* %14
%15 = tail call i32 @htons(i32 %0)
%16 = getelementptr inbounds %struct.sockaddr_in, %struct.sockaddr_in* %2, i64 0, i32 1
store i32 %15, i32* %16
%17 = load i32, i32* @INADDR_ANY
%18 = getelementptr inbounds %struct.sockaddr_in, %struct.sockaddr_in* %2, i64 0, i32 0, i32 0
store i32 %17, i32* %18
%19 = bitcast %struct.sockaddr_in* %2 to %struct.sockaddr*
%20 = call i32 @bind(i32 %6, %struct.sockaddr* %19, i32 12)
%21 = icmp eq i32 %20, -1
br i1 %21, label %22, label %25
22: ; preds = %11
%23 = load i32, i32* @errno
%24 = call i32 @err(i32 %23, i8* getelementptr inbounds ([5 x i8], [5 x i8]* @.str.1, i64 0, i64 0))
br label %25
25: ; preds = %22, %11
ret i32 %6
}