#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 */
typedef int /*<<< orphan*/ FILE;

/* Variables and functions */
int /*<<< orphan*/ fclose(int /*<<< orphan*/ *);
int /*<<< orphan*/ *fopen(char *, char *);
int /*<<< orphan*/ fscanf(int /*<<< orphan*/ *, char *, int *);
int get_online_cpu_from_sysfs(void) {
  FILE *f;
  int cpu = -1;
  f = fopen("/sys/devices/system/cpu/online", "r");
  if (!f)
    return -1;
  fscanf(f, "%d", &cpu);
  fclose(f);
  return cpu;
}


x86 assembly (clang, -O0):
<get_online_cpu_from_sysfs>:
push   %rbp
mov    %rsp,%rbp
sub    $0x20,%rsp
movl   $0xffffffff,-0x14(%rbp)
lea    0xeba(%rip),%rdi
lea    0xed2(%rip),%rsi
call   1050 <fopen@plt>
mov    %rax,-0x10(%rbp)
cmpq   $0x0,-0x10(%rbp)
jne    116d <get_online_cpu_from_sysfs+0x3d>
movl   $0xffffffff,-0x4(%rbp)
jmp    1190 <get_online_cpu_from_sysfs+0x60>
mov    -0x10(%rbp),%rdi
lea    0xea9(%rip),%rsi
lea    -0x14(%rbp),%rdx
call   1040 <fscanf@plt>
mov    -0x10(%rbp),%rdi
call   1030 <fclose@plt>
mov    -0x14(%rbp),%eax
mov    %eax,-0x4(%rbp)
mov    -0x4(%rbp),%eax
add    $0x20,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<get_online_cpu_from_sysfs>:
push   %rbx
sub    $0x10,%rsp
movl   $0xffffffff,0xc(%rsp)
ff
lea    0xebc(%rip),%rdi
lea    0xed4(%rip),%rsi
call   1050 <fopen@plt>
test   %rax,%rax
je     117a <get_online_cpu_from_sysfs+0x4a>
mov    %rax,%rbx
lea    0xec2(%rip),%rsi
lea    0xc(%rsp),%rdx
mov    %rax,%rdi
call   1040 <fscanf@plt>
mov    %rbx,%rdi
call   1030 <fclose@plt>
mov    0xc(%rsp),%eax
jmp    117f <get_online_cpu_from_sysfs+0x4f>
mov    $0xffffffff,%eax
add    $0x10,%rsp
pop    %rbx
ret

LLVM IR (-O0):
@.str = [31 x i8] c"/sys/devices/system/cpu/online\00"
@.str.1 = [2 x i8] c"r\00"
@.str.2 = [3 x i8] c"%d\00"
define i32 @get_online_cpu_from_sysfs() {
%1 = alloca i32
%2 = alloca i32*
%3 = alloca i32
store i32 -1, i32* %3
%4 = call i32* @fopen(i8* getelementptr inbounds ([31 x i8], [31 x i8]* @.str, i64 0, i64 0), i8* getelementptr inbounds ([2 x i8], [2 x i8]* @.str.1, i64 0, i64 0))
store i32* %4, i32** %2
%5 = load i32*, i32** %2
%6 = icmp ne i32* %5, null
br i1 %6, label %8, label %7
7: ; preds = %0
store i32 -1, i32* %1
br label %14
8: ; preds = %0
%9 = load i32*, i32** %2
%10 = call i32 @fscanf(i32* %9, i8* getelementptr inbounds ([3 x i8], [3 x i8]* @.str.2, i64 0, i64 0), i32* %3)
%11 = load i32*, i32** %2
%12 = call i32 @fclose(i32* %11)
%13 = load i32, i32* %3
store i32 %13, i32* %1
br label %14
14: ; preds = %8, %7
%15 = load i32, i32* %1
ret i32 %15
}

LLVM IR (-O2):
@.str = [31 x i8] c"/sys/devices/system/cpu/online\00"
@.str.1 = [2 x i8] c"r\00"
@.str.2 = [3 x i8] c"%d\00"
define i32 @get_online_cpu_from_sysfs() {
%1 = alloca i32
%2 = bitcast i32* %1 to i8*
store i32 -1, i32* %1
%3 = tail call i32* @fopen(i8* getelementptr inbounds ([31 x i8], [31 x i8]* @.str, i64 0, i64 0), i8* getelementptr inbounds ([2 x i8], [2 x i8]* @.str.1, i64 0, i64 0))
%4 = icmp eq i32* %3, null
br i1 %4, label %9, label %5
5: ; preds = %0
%6 = call i32 @fscanf(i32* %3, i8* getelementptr inbounds ([3 x i8], [3 x i8]* @.str.2, i64 0, i64 0), i32* %1)
%7 = call i32 @fclose(i32* %3)
%8 = load i32, i32* %1
br label %9
9: ; preds = %0, %5
%10 = phi i32 [ %8, %5 ], [ -1, %0 ]
ret i32 %10
}