#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*/ uint64_t;
typedef int /*<<< orphan*/ FILE;

/* Variables and functions */
int /*<<< orphan*/ fclose(int /*<<< orphan*/ *);
int /*<<< orphan*/ *fopen(char const *, char *);
int /*<<< orphan*/ fscanf(int /*<<< orphan*/ *, char *, int /*<<< orphan*/ *);
uint64_t read_sysfs_file(const char *name) {
  uint64_t retval;
  FILE *fp = NULL;
  fp = fopen(name, "r");
  if (!fp)
    return 0;
  fscanf(fp, "%lld", &retval);
  fclose(fp);
  return retval;
}


x86 assembly (clang, -O0):
<read_sysfs_file>:
push   %rbp
mov    %rsp,%rbp
sub    $0x20,%rsp
mov    %rdi,-0x10(%rbp)
movq   $0x0,-0x20(%rbp)
mov    -0x10(%rbp),%rdi
lea    0xeb1(%rip),%rsi
call   1050 <fopen@plt>
mov    %rax,-0x20(%rbp)
cmpq   $0x0,-0x20(%rbp)
jne    116f <read_sysfs_file+0x3f>
movl   $0x0,-0x4(%rbp)
jmp    1192 <read_sysfs_file+0x62>
mov    -0x20(%rbp),%rdi
lea    0xe88(%rip),%rsi
lea    -0x14(%rbp),%rdx
call   1040 <fscanf@plt>
mov    -0x20(%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):
<read_sysfs_file>:
push   %rbx
sub    $0x10,%rsp
lea    0xec4(%rip),%rsi
call   1050 <fopen@plt>
test   %rax,%rax
je     116b <read_sysfs_file+0x3b>
mov    %rax,%rbx
lea    0xeb2(%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    116d <read_sysfs_file+0x3d>
xor    %eax,%eax
add    $0x10,%rsp
pop    %rbx
ret

LLVM IR (-O0):
@.str = [2 x i8] c"r\00"
@.str.1 = [5 x i8] c"%lld\00"
define i32 @read_sysfs_file(i8* %0) {
%2 = alloca i32
%3 = alloca i8*
%4 = alloca i32
%5 = alloca i32*
store i8* %0, i8** %3
store i32* null, i32** %5
%6 = load i8*, i8** %3
%7 = call i32* @fopen(i8* %6, i8* getelementptr inbounds ([2 x i8], [2 x i8]* @.str, i64 0, i64 0))
store i32* %7, i32** %5
%8 = load i32*, i32** %5
%9 = icmp ne i32* %8, null
br i1 %9, label %11, label %10
10: ; preds = %1
store i32 0, i32* %2
br label %17
11: ; preds = %1
%12 = load i32*, i32** %5
%13 = call i32 @fscanf(i32* %12, i8* getelementptr inbounds ([5 x i8], [5 x i8]* @.str.1, i64 0, i64 0), i32* %4)
%14 = load i32*, i32** %5
%15 = call i32 @fclose(i32* %14)
%16 = load i32, i32* %4
store i32 %16, i32* %2
br label %17
17: ; preds = %11, %10
%18 = load i32, i32* %2
ret i32 %18
}

LLVM IR (-O2):
@.str = [2 x i8] c"r\00"
@.str.1 = [5 x i8] c"%lld\00"
define i32 @read_sysfs_file(i8* nocapture %0) {
%2 = alloca i32
%3 = bitcast i32* %2 to i8*
%4 = tail call i32* @fopen(i8* %0, i8* getelementptr inbounds ([2 x i8], [2 x i8]* @.str, i64 0, i64 0))
%5 = icmp eq i32* %4, null
br i1 %5, label %10, label %6
6: ; preds = %1
%7 = call i32 @fscanf(i32* %4, i8* getelementptr inbounds ([5 x i8], [5 x i8]* @.str.1, i64 0, i64 0), i32* %2)
%8 = call i32 @fclose(i32* %4)
%9 = load i32, i32* %2
br label %10
10: ; preds = %1, %6
%11 = phi i32 [ %9, %6 ], [ 0, %1 ]
ret i32 %11
}