#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 /*<<< orphan*/ fread(char *, int, int, int /*<<< orphan*/ *);
int /*<<< orphan*/ fseek(int /*<<< orphan*/ *, long, int /*<<< orphan*/);
int ftell(int /*<<< orphan*/ *);
char *malloc(int);
int /*<<< orphan*/ rewind(int /*<<< orphan*/ *);
char *read_file(const char *fname) {
  FILE *f;
  char *buf;
  int size;
  f = fopen(fname, "r");
  if (!f)
    return 0;
  fseek(f, 0l, SEEK_END);
  size = ftell(f);
  rewind(f);
  buf = malloc(size + 1);
  if (!buf) {
    fclose(f);
    return 0;
  }
  fread(buf, size, 1, f);
  buf[size] = 0;
  fclose(f);
  return buf;
}


x86 assembly (clang, -O0):
<read_file>:
push   %rbp
mov    %rsp,%rbp
sub    $0x30,%rsp
mov    %rdi,-0x10(%rbp)
mov    -0x10(%rbp),%rdi
lea    0xe79(%rip),%rsi
call   1090 <fopen@plt>
mov    %rax,-0x18(%rbp)
cmpq   $0x0,-0x18(%rbp)
jne    11a8 <read_file+0x38>
movq   $0x0,-0x8(%rbp)
jmp    1235 <read_file+0xc5>
mov    -0x18(%rbp),%rdi
mov    0x2e35(%rip),%rax
mov    (%rax),%edx
xor    %eax,%eax
mov    %eax,%esi
call   1080 <fseek@plt>
mov    -0x18(%rbp),%rdi
call   1060 <ftell@plt>
mov    %eax,-0x24(%rbp)
mov    -0x18(%rbp),%rdi
call   1050 <rewind@plt>
mov    -0x24(%rbp),%edi
add    $0x1,%edi
call   1070 <malloc@plt>
mov    %rax,-0x20(%rbp)
cmpq   $0x0,-0x20(%rbp)
jne    1203 <read_file+0x93>
mov    -0x18(%rbp),%rdi
call   1040 <fclose@plt>
movq   $0x0,-0x8(%rbp)
jmp    1235 <read_file+0xc5>
mov    -0x20(%rbp),%rdi
mov    -0x24(%rbp),%esi
mov    -0x18(%rbp),%rcx
mov    $0x1,%edx
call   1030 <fread@plt>
mov    -0x20(%rbp),%rax
movslq -0x24(%rbp),%rcx
movb   $0x0,(%rax,%rcx,1)
mov    -0x18(%rbp),%rdi
call   1040 <fclose@plt>
mov    -0x20(%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   %r12
push   %rbx
push   %rax
lea    0xe81(%rip),%rsi
call   1090 <fopen@plt>
test   %rax,%rax
je     11ee <read_file+0x7e>
mov    %rax,%rbx
mov    0x2e55(%rip),%rax
mov    (%rax),%edx
xor    %r14d,%r14d
mov    %rbx,%rdi
xor    %esi,%esi
call   1080 <fseek@plt>
mov    %rbx,%rdi
call   1060 <ftell@plt>
mov    %eax,%r15d
mov    %rbx,%rdi
call   1050 <rewind@plt>
lea    0x1(%r15),%edi
call   1070 <malloc@plt>
test   %rax,%rax
je     11e4 <read_file+0x74>
mov    %rax,%r12
mov    %rax,%rdi
mov    %r15d,%esi
mov    $0x1,%edx
mov    %rbx,%rcx
call   1030 <fread@plt>
movslq %r15d,%rax
movb   $0x0,(%r12,%rax,1)
mov    %r12,%r14
mov    %rbx,%rdi
call   1040 <fclose@plt>
jmp    11f1 <read_file+0x81>
xor    %r14d,%r14d
mov    %r14,%rax
add    $0x8,%rsp
pop    %rbx
pop    %r12
pop    %r14
pop    %r15
ret

LLVM IR (-O0):
@.str = [2 x i8] c"r\00"
@SEEK_END = global i32 0
define i8* @read_file(i8* %0) {
%2 = alloca i8*
%3 = alloca i8*
%4 = alloca i32*
%5 = alloca i8*
%6 = alloca i32
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 %12, label %11
11: ; preds = %1
store i8* null, i8** %2
br label %40
12: ; preds = %1
%13 = load i32*, i32** %4
%14 = load i32, i32* @SEEK_END
%15 = call i32 @fseek(i32* %13, i64 0, i32 %14)
%16 = load i32*, i32** %4
%17 = call i32 @ftell(i32* %16)
store i32 %17, i32* %6
%18 = load i32*, i32** %4
%19 = call i32 @rewind(i32* %18)
%20 = load i32, i32* %6
%21 = add nsw i32 %20, 1
%22 = call i8* @malloc(i32 %21)
store i8* %22, i8** %5
%23 = load i8*, i8** %5
%24 = icmp ne i8* %23, null
br i1 %24, label %28, label %25
25: ; preds = %12
%26 = load i32*, i32** %4
%27 = call i32 @fclose(i32* %26)
store i8* null, i8** %2
br label %40
28: ; preds = %12
%29 = load i8*, i8** %5
%30 = load i32, i32* %6
%31 = load i32*, i32** %4
%32 = call i32 @fread(i8* %29, i32 %30, i32 1, i32* %31)
%33 = load i8*, i8** %5
%34 = load i32, i32* %6
%35 = sext i32 %34 to i64
%36 = getelementptr inbounds i8, i8* %33, i64 %35
store i8 0, i8* %36
%37 = load i32*, i32** %4
%38 = call i32 @fclose(i32* %37)
%39 = load i8*, i8** %5
store i8* %39, i8** %2
br label %40
40: ; preds = %28, %25, %11
%41 = load i8*, i8** %2
ret i8* %41
}

LLVM IR (-O2):
@.str = [2 x i8] c"r\00"
@SEEK_END = global i32 0
define noalias i8* @read_file(i8* nocapture %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 %19, label %4
4: ; preds = %1
%5 = load i32, i32* @SEEK_END
%6 = tail call i32 @fseek(i32* %2, i64 0, i32 %5)
%7 = tail call i32 @ftell(i32* %2)
%8 = tail call i32 @rewind(i32* %2)
%9 = add nsw i32 %7, 1
%10 = tail call i8* @malloc(i32 %9)
%11 = icmp eq i8* %10, null
br i1 %11, label %16, label %12
12: ; preds = %4
%13 = tail call i32 @fread(i8* %10, i32 %7, i32 1, i32* %2)
%14 = sext i32 %7 to i64
%15 = getelementptr inbounds i8, i8* %10, i64 %14
store i8 0, i8* %15
br label %16
16: ; preds = %4, %12
%17 = phi i8* [ %10, %12 ], [ null, %4 ]
%18 = tail call i32 @fclose(i32* %2)
br label %19
19: ; preds = %16, %1
%20 = phi i8* [ null, %1 ], [ %17, %16 ]
ret i8* %20
}