#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*/ SEEK_END;
int /*<<< orphan*/ fclose(int /*<<< orphan*/ *);
int /*<<< orphan*/ *fopen(char const *, char *);
int fread(char *, size_t, int, int /*<<< orphan*/ *);
int /*<<< orphan*/ free(char *);
int /*<<< orphan*/ fseek(int /*<<< orphan*/ *, int /*<<< orphan*/,
                         int /*<<< orphan*/);
int /*<<< orphan*/ ftell(int /*<<< orphan*/ *);
scalar_t__ malloc(size_t);
int /*<<< orphan*/ printf(char *, char const *);
int /*<<< orphan*/ rewind(int /*<<< orphan*/ *);
char *read_file(const char *filename) {
  FILE *fp = fopen(filename, "r");
  if (!fp) {
    printf("Could not open file %s\n", filename);
    return NULL;
  }
  fseek(fp, 0, SEEK_END);
  size_t size = (size_t)ftell(fp);
  rewind(fp);
  char *answer = (char *)malloc(size + 1);
  if (!answer) {
    fclose(fp);
    return NULL;
  }
  if (fread(answer, size, 1, fp) != 1) {
    free(answer);
    return NULL;
  }
  answer[size] = '\0';
  fclose(fp);
  return answer;
}


x86 assembly (clang, -O0):
<read_file>:
push   %rbp
mov    %rsp,%rbp
sub    $0x30,%rsp
mov    %rdi,-0x10(%rbp)
mov    -0x10(%rbp),%rdi
lea    0xe59(%rip),%rsi
call   10b0 <fopen@plt>
mov    %rax,-0x18(%rbp)
cmpq   $0x0,-0x18(%rbp)
jne    11d8 <read_file+0x48>
mov    -0x10(%rbp),%rsi
lea    0xe3c(%rip),%rdi
call   1060 <printf@plt>
movq   $0x0,-0x8(%rbp)
jmp    1288 <read_file+0xf8>
mov    -0x18(%rbp),%rdi
mov    0x2e05(%rip),%rax
mov    (%rax),%edx
xor    %esi,%esi
call   10a0 <fseek@plt>
mov    -0x18(%rbp),%rdi
call   1080 <ftell@plt>
cltq
mov    %rax,-0x20(%rbp)
mov    -0x18(%rbp),%rdi
call   1070 <rewind@plt>
mov    -0x20(%rbp),%rdi
add    $0x1,%rdi
call   1090 <malloc@plt>
mov    %rax,-0x28(%rbp)
cmpq   $0x0,-0x28(%rbp)
jne    1236 <read_file+0xa6>
mov    -0x18(%rbp),%rdi
call   1050 <fclose@plt>
movq   $0x0,-0x8(%rbp)
jmp    1288 <read_file+0xf8>
mov    -0x28(%rbp),%rdi
mov    -0x20(%rbp),%rsi
mov    -0x18(%rbp),%rcx
mov    $0x1,%edx
call   1040 <fread@plt>
cmp    $0x1,%eax
je     126b <read_file+0xdb>
mov    -0x28(%rbp),%rdi
call   1030 <free@plt>
movq   $0x0,-0x8(%rbp)
jmp    1288 <read_file+0xf8>
mov    -0x28(%rbp),%rax
mov    -0x20(%rbp),%rcx
movb   $0x0,(%rax,%rcx,1)
mov    -0x18(%rbp),%rdi
call   1050 <fclose@plt>
mov    -0x28(%rbp),%rax
mov    %rax,-0x8(%rbp)
mov    -0x8(%rbp),%rax
add    $0x30,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<read_file>:
push   %r15
push   %r14
push   %rbx
mov    %rdi,%r14
lea    0xe61(%rip),%rsi
call   10b0 <fopen@plt>
test   %rax,%rax
je     120a <read_file+0x7a>
mov    %rax,%rbx
mov    0x2e35(%rip),%rax
mov    (%rax),%edx
mov    %rbx,%rdi
xor    %esi,%esi
call   10a0 <fseek@plt>
mov    %rbx,%rdi
call   1080 <ftell@plt>
movslq %eax,%r15
mov    %rbx,%rdi
call   1070 <rewind@plt>
lea    0x1(%r15),%rdi
call   1090 <malloc@plt>
test   %rax,%rax
je     121b <read_file+0x8b>
mov    %rax,%r14
mov    %rax,%rdi
mov    %r15,%rsi
mov    $0x1,%edx
mov    %rbx,%rcx
call   1040 <fread@plt>
cmp    $0x1,%eax
jne    1225 <read_file+0x95>
movb   $0x0,(%r14,%r15,1)
mov    %rbx,%rdi
call   1050 <fclose@plt>
jmp    1230 <read_file+0xa0>
lea    0xdf1(%rip),%rdi
mov    %r14,%rsi
call   1060 <printf@plt>
jmp    122d <read_file+0x9d>
mov    %rbx,%rdi
call   1050 <fclose@plt>
jmp    122d <read_file+0x9d>
mov    %r14,%rdi
call   1030 <free@plt>
xor    %r14d,%r14d
mov    %r14,%rax
pop    %rbx
pop    %r14
pop    %r15
ret

LLVM IR (-O0):
@.str = [2 x i8] c"r\00"
@.str.1 = [24 x i8] c"Could not open file %s\0A\00"
@SEEK_END = global i32 0
define i8* @read_file(i8* %0) {
%2 = alloca i8*
%3 = alloca i8*
%4 = alloca i32*
%5 = alloca i64
%6 = alloca i8*
store i8* %0, i8** %3
%7 = load i8*, i8** %3
%8 = call i32* @fopen(i8* %7, i8* getelementptr inbounds ([2 x i8], [2 x i8]* @.str, i64 0, i64 0))
store i32* %8, i32** %4
%9 = load i32*, i32** %4
%10 = icmp ne i32* %9, null
br i1 %10, label %14, label %11
11: ; preds = %1
%12 = load i8*, i8** %3
%13 = call i32 @printf(i8* getelementptr inbounds ([24 x i8], [24 x i8]* @.str.1, i64 0, i64 0), i8* %12)
store i8* null, i8** %2
br label %48
14: ; preds = %1
%15 = load i32*, i32** %4
%16 = load i32, i32* @SEEK_END
%17 = call i32 @fseek(i32* %15, i32 0, i32 %16)
%18 = load i32*, i32** %4
%19 = call i32 @ftell(i32* %18)
%20 = sext i32 %19 to i64
store i64 %20, i64* %5
%21 = load i32*, i32** %4
%22 = call i32 @rewind(i32* %21)
%23 = load i64, i64* %5
%24 = add i64 %23, 1
%25 = call i64 @malloc(i64 %24)
%26 = inttoptr i64 %25 to i8*
store i8* %26, i8** %6
%27 = load i8*, i8** %6
%28 = icmp ne i8* %27, null
br i1 %28, label %32, label %29
29: ; preds = %14
%30 = load i32*, i32** %4
%31 = call i32 @fclose(i32* %30)
store i8* null, i8** %2
br label %48
32: ; preds = %14
%33 = load i8*, i8** %6
%34 = load i64, i64* %5
%35 = load i32*, i32** %4
%36 = call i32 @fread(i8* %33, i64 %34, i32 1, i32* %35)
%37 = icmp ne i32 %36, 1
br i1 %37, label %38, label %41
38: ; preds = %32
%39 = load i8*, i8** %6
%40 = call i32 @free(i8* %39)
store i8* null, i8** %2
br label %48
41: ; preds = %32
%42 = load i8*, i8** %6
%43 = load i64, i64* %5
%44 = getelementptr inbounds i8, i8* %42, i64 %43
store i8 0, i8* %44
%45 = load i32*, i32** %4
%46 = call i32 @fclose(i32* %45)
%47 = load i8*, i8** %6
store i8* %47, i8** %2
br label %48
48: ; preds = %41, %38, %29, %11
%49 = load i8*, i8** %2
ret i8* %49
}

LLVM IR (-O2):
@.str = [2 x i8] c"r\00"
@.str.1 = [24 x i8] c"Could not open file %s\0A\00"
@SEEK_END = global i32 0
define i8* @read_file(i8* %0) {
%2 = tail call i32* @fopen(i8* %0, i8* getelementptr inbounds ([2 x i8], [2 x i8]* @.str, i64 0, i64 0))
%3 = icmp eq i32* %2, null
br i1 %3, label %4, label %6
4: ; preds = %1
%5 = tail call i32 @printf(i8* getelementptr inbounds ([24 x i8], [24 x i8]* @.str.1, i64 0, i64 0), i8* %0)
br label %26
6: ; preds = %1
%7 = load i32, i32* @SEEK_END
%8 = tail call i32 @fseek(i32* %2, i32 0, i32 %7)
%9 = tail call i32 @ftell(i32* %2)
%10 = sext i32 %9 to i64
%11 = tail call i32 @rewind(i32* %2)
%12 = add nsw i64 %10, 1
%13 = tail call i64 @malloc(i64 %12)
%14 = inttoptr i64 %13 to i8*
%15 = icmp eq i64 %13, 0
br i1 %15, label %16, label %18
16: ; preds = %6
%17 = tail call i32 @fclose(i32* %2)
br label %26
18: ; preds = %6
%19 = tail call i32 @fread(i8* %14, i64 %10, i32 1, i32* %2)
%20 = icmp eq i32 %19, 1
br i1 %20, label %23, label %21
21: ; preds = %18
%22 = tail call i32 @free(i8* %14)
br label %26
23: ; preds = %18
%24 = getelementptr inbounds i8, i8* %14, i64 %10
store i8 0, i8* %24
%25 = tail call i32 @fclose(i32* %2)
br label %26
26: ; preds = %16, %21, %23, %4
%27 = phi i8* [ null, %4 ], [ null, %21 ], [ %14, %23 ], [ null, %16 ]
ret i8* %27
}