#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*/ F_SETFL;
int O_NDELAY;
int O_RDWR;
int /*<<< orphan*/ fcntl(int, int /*<<< orphan*/, int /*<<< orphan*/);
int open(char *, int);
int /*<<< orphan*/ perror(char *);
int open_port(void) {
  int fd;
  fd = open("/dev/ttyS0", O_RDWR | O_NDELAY);
  if (fd == -1) {
    perror("open_port: Unable to open /dev/ttyS0 - ");
  } else {
    fcntl(fd, F_SETFL, 0);
  }
  return (fd);
}


x86 assembly (clang, -O0):
<open_port>:
push   %rbp
mov    %rsp,%rbp
sub    $0x10,%rsp
mov    0x2ea9(%rip),%rax
mov    (%rax),%esi
mov    0x2e88(%rip),%rax
or     (%rax),%esi
lea    0xeaf(%rip),%rdi
call   1040 <open@plt>
mov    %eax,-0x4(%rbp)
cmpl   $0xffffffff,-0x4(%rbp)
jne    1174 <open_port+0x44>
lea    0xea1(%rip),%rdi
call   1050 <perror@plt>
jmp    1187 <open_port+0x57>
mov    -0x4(%rbp),%edi
mov    0x2e5a(%rip),%rax
mov    (%rax),%esi
xor    %edx,%edx
call   1030 <fcntl@plt>
mov    -0x4(%rbp),%eax
add    $0x10,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<open_port>:
push   %rbx
mov    0x2eb0(%rip),%rax
mov    0x2e91(%rip),%rcx
mov    (%rcx),%esi
or     (%rax),%esi
lea    0xeb6(%rip),%rdi
call   1040 <open@plt>
mov    %eax,%ebx
cmp    $0xffffffff,%eax
je     116c <open_port+0x3c>
mov    0x2e7b(%rip),%rax
mov    (%rax),%esi
mov    %ebx,%edi
xor    %edx,%edx
call   1030 <fcntl@plt>
mov    %ebx,%eax
pop    %rbx
ret
lea    0xe98(%rip),%rdi
call   1050 <perror@plt>
jmp    1168 <open_port+0x38>

LLVM IR (-O0):
@.str = [11 x i8] c"/dev/ttyS0\00"
@O_RDWR = global i32 0
@O_NDELAY = global i32 0
@.str.1 = [40 x i8] c"open_port: Unable to open /dev/ttyS0 - \00"
@F_SETFL = global i32 0
define i32 @open_port() {
%1 = alloca i32
%2 = load i32, i32* @O_RDWR
%3 = load i32, i32* @O_NDELAY
%4 = or i32 %2, %3
%5 = call i32 @open(i8* getelementptr inbounds ([11 x i8], [11 x i8]* @.str, i64 0, i64 0), i32 %4)
store i32 %5, i32* %1
%6 = load i32, i32* %1
%7 = icmp eq i32 %6, -1
br i1 %7, label %8, label %10
8: ; preds = %0
%9 = call i32 @perror(i8* getelementptr inbounds ([40 x i8], [40 x i8]* @.str.1, i64 0, i64 0))
br label %14
10: ; preds = %0
%11 = load i32, i32* %1
%12 = load i32, i32* @F_SETFL
%13 = call i32 @fcntl(i32 %11, i32 %12, i32 0)
br label %14
14: ; preds = %10, %8
%15 = load i32, i32* %1
ret i32 %15
}

LLVM IR (-O2):
@.str = [11 x i8] c"/dev/ttyS0\00"
@O_RDWR = global i32 0
@O_NDELAY = global i32 0
@.str.1 = [40 x i8] c"open_port: Unable to open /dev/ttyS0 - \00"
@F_SETFL = global i32 0
define i32 @open_port() {
%1 = load i32, i32* @O_RDWR
%2 = load i32, i32* @O_NDELAY
%3 = or i32 %2, %1
%4 = tail call i32 @open(i8* getelementptr inbounds ([11 x i8], [11 x i8]* @.str, i64 0, i64 0), i32 %3)
%5 = icmp eq i32 %4, -1
br i1 %5, label %6, label %8
6: ; preds = %0
%7 = tail call i32 @perror(i8* getelementptr inbounds ([40 x i8], [40 x i8]* @.str.1, i64 0, i64 0))
br label %11
8: ; preds = %0
%9 = load i32, i32* @F_SETFL
%10 = tail call i32 @fcntl(i32 %4, i32 %9, i32 0)
br label %11
11: ; preds = %8, %6
ret i32 %4
}