#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*/ err(char *);
int /*<<< orphan*/ fclose(int /*<<< orphan*/ *);
int /*<<< orphan*/ *fopen(char *, char *);
int fprintf(int /*<<< orphan*/ *, char *, int);
void set_backlight(int br) {
  FILE *f = fopen("/sys/class/backlight/acpi_video0"
                  "/brightness",
                  "w");
  if (f == NULL)
    err("can't open screen brightness file to write");
  if (fprintf(f, "%d", br) < 1)
    err("can't write new brightness");
  fclose(f);
}


x86 assembly (clang, -O0):
<set_backlight>:
push   %rbp
mov    %rsp,%rbp
sub    $0x10,%rsp
mov    %edi,-0x4(%rbp)
lea    0xeae(%rip),%rdi
lea    0xed3(%rip),%rsi
call   1060 <fopen@plt>
mov    %rax,-0x10(%rbp)
cmpq   $0x0,-0x10(%rbp)
jne    1179 <set_backlight+0x39>
lea    0xeba(%rip),%rdi
call   1050 <err@plt>
mov    -0x10(%rbp),%rdi
mov    -0x4(%rbp),%edx
lea    0xed2(%rip),%rsi
call   1040 <fprintf@plt>
cmp    $0x1,%eax
jge    11a1 <set_backlight+0x61>
lea    0xec0(%rip),%rdi
call   1050 <err@plt>
mov    -0x10(%rbp),%rdi
call   1030 <fclose@plt>
add    $0x10,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<set_backlight>:
push   %rbp
push   %rbx
push   %rax
mov    %edi,%ebp
lea    0xeb4(%rip),%rdi
lea    0xed9(%rip),%rsi
call   1060 <fopen@plt>
mov    %rax,%rbx
test   %rax,%rax
jne    116c <set_backlight+0x2c>
lea    0xec7(%rip),%rdi
call   1050 <err@plt>
lea    0xee6(%rip),%rsi
mov    %rbx,%rdi
mov    %ebp,%edx
call   1040 <fprintf@plt>
test   %eax,%eax
jg     118d <set_backlight+0x4d>
lea    0xed4(%rip),%rdi
call   1050 <err@plt>
mov    %rbx,%rdi
add    $0x8,%rsp
pop    %rbx
pop    %rbp
jmp    1030 <fclose@plt>

LLVM IR (-O0):
@.str = [44 x i8] c"/sys/class/backlight/acpi_video0/brightness\00"
@.str.1 = [2 x i8] c"w\00"
@.str.2 = [43 x i8] c"can't open screen brightness file to write\00"
@.str.3 = [3 x i8] c"%d\00"
@.str.4 = [27 x i8] c"can't write new brightness\00"
define void @set_backlight(i32 %0) {
%2 = alloca i32
%3 = alloca i32*
store i32 %0, i32* %2
%4 = call i32* @fopen(i8* getelementptr inbounds ([44 x i8], [44 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** %3
%5 = load i32*, i32** %3
%6 = icmp eq i32* %5, null
br i1 %6, label %7, label %9
7: ; preds = %1
%8 = call i32 @err(i8* getelementptr inbounds ([43 x i8], [43 x i8]* @.str.2, i64 0, i64 0))
br label %9
9: ; preds = %7, %1
%10 = load i32*, i32** %3
%11 = load i32, i32* %2
%12 = call i32 @fprintf(i32* %10, i8* getelementptr inbounds ([3 x i8], [3 x i8]* @.str.3, i64 0, i64 0), i32 %11)
%13 = icmp slt i32 %12, 1
br i1 %13, label %14, label %16
14: ; preds = %9
%15 = call i32 @err(i8* getelementptr inbounds ([27 x i8], [27 x i8]* @.str.4, i64 0, i64 0))
br label %16
16: ; preds = %14, %9
%17 = load i32*, i32** %3
%18 = call i32 @fclose(i32* %17)
ret void
}

LLVM IR (-O2):
@.str = [44 x i8] c"/sys/class/backlight/acpi_video0/brightness\00"
@.str.1 = [2 x i8] c"w\00"
@.str.2 = [43 x i8] c"can't open screen brightness file to write\00"
@.str.3 = [3 x i8] c"%d\00"
@.str.4 = [27 x i8] c"can't write new brightness\00"
define void @set_backlight(i32 %0) {
%2 = tail call i32* @fopen(i8* getelementptr inbounds ([44 x i8], [44 x i8]* @.str, i64 0, i64 0), i8* getelementptr inbounds ([2 x i8], [2 x i8]* @.str.1, i64 0, i64 0))
%3 = icmp eq i32* %2, null
br i1 %3, label %4, label %6
4: ; preds = %1
%5 = tail call i32 @err(i8* getelementptr inbounds ([43 x i8], [43 x i8]* @.str.2, i64 0, i64 0))
br label %6
6: ; preds = %4, %1
%7 = tail call i32 @fprintf(i32* %2, i8* getelementptr inbounds ([3 x i8], [3 x i8]* @.str.3, i64 0, i64 0), i32 %0)
%8 = icmp slt i32 %7, 1
br i1 %8, label %9, label %11
9: ; preds = %6
%10 = tail call i32 @err(i8* getelementptr inbounds ([27 x i8], [27 x i8]* @.str.4, i64 0, i64 0))
br label %11
11: ; preds = %9, %6
%12 = tail call i32 @fclose(i32* %2)
ret void
}