#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 O_NDELAY;
int O_NOCTTY;
int O_RDWR;
int /*<<< orphan*/ errno;
int /*<<< orphan*/ fprintf(int /*<<< orphan*/, char *, char *);
int open(char *, int);
int /*<<< orphan*/ stderr;
char *strerror(int /*<<< orphan*/);
int open_port(void) {
  int fd;
  fd = open("/dev/ttyUSB0", O_RDWR | O_NOCTTY | O_NDELAY);
  if (-1 == fd) {
    fprintf(stderr, "open port: error %s\n", strerror(errno));
  }
  return fd;
}


x86 assembly (clang, -O0):
<open_port>:
push   %rbp
mov    %rsp,%rbp
sub    $0x10,%rsp
mov    0x2ea9(%rip),%rax
mov    (%rax),%esi
mov    0x2e90(%rip),%rax
or     (%rax),%esi
mov    0x2e6f(%rip),%rax
or     (%rax),%esi
lea    0xea6(%rip),%rdi
call   1040 <open@plt>
mov    %eax,-0x4(%rbp)
mov    $0xffffffff,%eax
cmp    -0x4(%rbp),%eax
jne    119c <open_port+0x6c>
mov    0x2e59(%rip),%rax
mov    (%rax),%eax
mov    %eax,-0x8(%rbp)
mov    0x2e45(%rip),%rax
mov    (%rax),%edi
call   1050 <strerror@plt>
mov    -0x8(%rbp),%edi
mov    %rax,%rdx
lea    0xe76(%rip),%rsi
call   1030 <fprintf@plt>
mov    -0x4(%rbp),%eax
add    $0x10,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<open_port>:
push   %rbp
push   %rbx
push   %rax
mov    0x2eae(%rip),%rax
mov    0x2e97(%rip),%rcx
mov    (%rcx),%esi
or     (%rax),%esi
mov    0x2e74(%rip),%rax
or     (%rax),%esi
lea    0xeab(%rip),%rdi
call   1040 <open@plt>
mov    %eax,%ebx
cmp    $0xffffffff,%eax
jne    1189 <open_port+0x59>
mov    0x2e68(%rip),%rax
mov    (%rax),%ebp
mov    0x2e57(%rip),%rax
mov    (%rax),%edi
call   1050 <strerror@plt>
lea    0xe8e(%rip),%rsi
mov    %ebp,%edi
mov    %rax,%rdx
call   1030 <fprintf@plt>
mov    %ebx,%eax
add    $0x8,%rsp
pop    %rbx
pop    %rbp
ret

LLVM IR (-O0):
@.str = [13 x i8] c"/dev/ttyUSB0\00"
@O_RDWR = global i32 0
@O_NOCTTY = global i32 0
@O_NDELAY = global i32 0
@stderr = global i32 0
@.str.1 = [21 x i8] c"open port: error %s\0A\00"
@errno = global i32 0
define i32 @open_port() {
%1 = alloca i32
%2 = load i32, i32* @O_RDWR
%3 = load i32, i32* @O_NOCTTY
%4 = or i32 %2, %3
%5 = load i32, i32* @O_NDELAY
%6 = or i32 %4, %5
%7 = call i32 @open(i8* getelementptr inbounds ([13 x i8], [13 x i8]* @.str, i64 0, i64 0), i32 %6)
store i32 %7, i32* %1
%8 = load i32, i32* %1
%9 = icmp eq i32 -1, %8
br i1 %9, label %10, label %15
10: ; preds = %0
%11 = load i32, i32* @stderr
%12 = load i32, i32* @errno
%13 = call i8* @strerror(i32 %12)
%14 = call i32 @fprintf(i32 %11, i8* getelementptr inbounds ([21 x i8], [21 x i8]* @.str.1, i64 0, i64 0), i8* %13)
br label %15
15: ; preds = %10, %0
%16 = load i32, i32* %1
ret i32 %16
}

LLVM IR (-O2):
@.str = [13 x i8] c"/dev/ttyUSB0\00"
@O_RDWR = global i32 0
@O_NOCTTY = global i32 0
@O_NDELAY = global i32 0
@stderr = global i32 0
@.str.1 = [21 x i8] c"open port: error %s\0A\00"
@errno = global i32 0
define i32 @open_port() {
%1 = load i32, i32* @O_RDWR
%2 = load i32, i32* @O_NOCTTY
%3 = or i32 %2, %1
%4 = load i32, i32* @O_NDELAY
%5 = or i32 %3, %4
%6 = tail call i32 @open(i8* getelementptr inbounds ([13 x i8], [13 x i8]* @.str, i64 0, i64 0), i32 %5)
%7 = icmp eq i32 %6, -1
br i1 %7, label %8, label %13
8: ; preds = %0
%9 = load i32, i32* @stderr
%10 = load i32, i32* @errno
%11 = tail call i8* @strerror(i32 %10)
%12 = tail call i32 @fprintf(i32 %9, i8* getelementptr inbounds ([21 x i8], [21 x i8]* @.str.1, i64 0, i64 0), i8* %11)
br label %13
13: ; preds = %8, %0
ret i32 %6
}