#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*/ exit(int);
int /*<<< orphan*/ fclose(int /*<<< orphan*/ *);
int /*<<< orphan*/ fgets(char *, unsigned int const, int /*<<< orphan*/ *);
int /*<<< orphan*/ *fopen(char *, char *);
int /*<<< orphan*/ printf(char *, char *);
void readFromFile(char *filename, char *buffer, const unsigned int max_length) {
  FILE *file = fopen(filename, "r");
  if (file == NULL) {
    printf("Error: Unable to open file %s for reading.\n", filename);
    exit(-1);
  }
  fgets(buffer, max_length, file);
  fclose(file);
}


x86 assembly (clang, -O0):
<readFromFile>:
push   %rbp
mov    %rsp,%rbp
sub    $0x20,%rsp
mov    %rdi,-0x8(%rbp)
mov    %rsi,-0x10(%rbp)
mov    %edx,-0x14(%rbp)
mov    -0x8(%rbp),%rdi
lea    0xe92(%rip),%rsi
call   1060 <fopen@plt>
mov    %rax,-0x20(%rbp)
cmpq   $0x0,-0x20(%rbp)
jne    119c <readFromFile+0x4c>
mov    -0x8(%rbp),%rsi
lea    0xe75(%rip),%rdi
call   1040 <printf@plt>
mov    $0xffffffff,%edi
call   1070 <exit@plt>
mov    -0x10(%rbp),%rdi
mov    -0x14(%rbp),%esi
mov    -0x20(%rbp),%rdx
call   1050 <fgets@plt>
mov    -0x20(%rbp),%rdi
call   1030 <fclose@plt>
add    $0x20,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<readFromFile>:
push   %rbp
push   %r15
push   %r14
push   %rbx
push   %rax
mov    %edx,%r14d
mov    %rsi,%r15
mov    %rdi,%rbx
lea    0xe99(%rip),%rsi
call   1060 <fopen@plt>
test   %rax,%rax
je     1194 <readFromFile+0x44>
mov    %rax,%rbp
mov    %r15,%rdi
mov    %r14d,%esi
mov    %rax,%rdx
call   1050 <fgets@plt>
mov    %rbp,%rdi
add    $0x8,%rsp
pop    %rbx
pop    %r14
pop    %r15
pop    %rbp
jmp    1030 <fclose@plt>
lea    0xe67(%rip),%rdi
mov    %rbx,%rsi
call   1040 <printf@plt>
mov    $0xffffffff,%edi
call   1070 <exit@plt>

LLVM IR (-O0):
@.str = [2 x i8] c"r\00"
@.str.1 = [44 x i8] c"Error: Unable to open file %s for reading.\0A\00"
define void @readFromFile(i8* %0, i8* %1, i32 %2) {
%4 = alloca i8*
%5 = alloca i8*
%6 = alloca i32
%7 = alloca i32*
store i8* %0, i8** %4
store i8* %1, i8** %5
store i32 %2, i32* %6
%8 = load i8*, i8** %4
%9 = call i32* @fopen(i8* %8, i8* getelementptr inbounds ([2 x i8], [2 x i8]* @.str, i64 0, i64 0))
store i32* %9, i32** %7
%10 = load i32*, i32** %7
%11 = icmp eq i32* %10, null
br i1 %11, label %12, label %16
12: ; preds = %3
%13 = load i8*, i8** %4
%14 = call i32 @printf(i8* getelementptr inbounds ([44 x i8], [44 x i8]* @.str.1, i64 0, i64 0), i8* %13)
%15 = call i32 @exit(i32 -1)
unreachable
16: ; preds = %3
%17 = load i8*, i8** %5
%18 = load i32, i32* %6
%19 = load i32*, i32** %7
%20 = call i32 @fgets(i8* %17, i32 %18, i32* %19)
%21 = load i32*, i32** %7
%22 = call i32 @fclose(i32* %21)
ret void
}

LLVM IR (-O2):
@.str = [2 x i8] c"r\00"
@.str.1 = [44 x i8] c"Error: Unable to open file %s for reading.\0A\00"
define void @readFromFile(i8* %0, i8* %1, i32 %2) {
%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 %6, label %9
6: ; preds = %3
%7 = tail call i32 @printf(i8* getelementptr inbounds ([44 x i8], [44 x i8]* @.str.1, i64 0, i64 0), i8* %0)
%8 = tail call i32 @exit(i32 -1)
unreachable
9: ; preds = %3
%10 = tail call i32 @fgets(i8* %1, i32 %2, i32* %4)
%11 = tail call i32 @fclose(i32* %4)
ret void
}