#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 */

/* Variables and functions */
int /*<<< orphan*/ exit_failure();
int /*<<< orphan*/ printf(char *);
int rand();
void check_chunk(unsigned char *chunk, int len) {
  int i;
  for (i = 0; i < len; i++) {
    if (chunk[i] != rand() % 256) {
      printf("ERROR: File did not contain same squence of data as when "
             "it was written!\n");
      exit_failure();
    }
  }
}


x86 assembly (clang, -O0):
<check_chunk>:
push   %rbp
mov    %rsp,%rbp
sub    $0x20,%rsp
mov    %rdi,-0x8(%rbp)
mov    %esi,-0xc(%rbp)
movl   $0x0,-0x10(%rbp)
mov    -0x10(%rbp),%eax
cmp    -0xc(%rbp),%eax
jge    11a1 <check_chunk+0x71>
mov    -0x8(%rbp),%rax
movslq -0x10(%rbp),%rcx
movzbl (%rax,%rcx,1),%eax
mov    %eax,-0x14(%rbp)
mov    $0x0,%al
call   1050 <rand@plt>
mov    $0x100,%ecx
cltd
idiv   %ecx
mov    -0x14(%rbp),%eax
cmp    %edx,%eax
je     118e <check_chunk+0x5e>
lea    0xe7e(%rip),%rdi
call   1030 <printf@plt>
mov    $0x0,%al
call   1040 <exit_failure@plt>
jmp    1193 <check_chunk+0x63>
mov    -0x10(%rbp),%eax
add    $0x1,%eax
mov    %eax,-0x10(%rbp)
jmp    1146 <check_chunk+0x16>
add    $0x20,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<check_chunk>:
push   %rbp
push   %r15
push   %r14
push   %r12
push   %rbx
test   %esi,%esi
jle    118d <check_chunk+0x5d>
mov    %rdi,%r15
mov    %esi,%r12d
lea    0xeb7(%rip),%r14
xor    %ebx,%ebx
jmp    1159 <check_chunk+0x29>
nopl   (%rax)
add    $0x1,%rbx
cmp    %rbx,%r12
je     118d <check_chunk+0x5d>
movzbl (%r15,%rbx,1),%ebp
xor    %eax,%eax
call   1050 <rand@plt>
lea    0xff(%rax),%ecx
test   %eax,%eax
cmovns %eax,%ecx
and    $0xffffff00,%ecx
sub    %ecx,%eax
cmp    %ebp,%eax
je     1150 <check_chunk+0x20>
mov    %r14,%rdi
call   1030 <puts@plt>
xor    %eax,%eax
call   1040 <exit_failure@plt>
jmp    1150 <check_chunk+0x20>
pop    %rbx
pop    %r12
pop    %r14
pop    %r15
pop    %rbp
ret

LLVM IR (-O0):
@.str = [74 x i8] c"ERROR: File did not contain same squence of data as when it was written!\0A\00"
define void @check_chunk(i8* %0, i32 %1) {
%3 = alloca i8*
%4 = alloca i32
%5 = alloca i32
store i8* %0, i8** %3
store i32 %1, i32* %4
store i32 0, i32* %5
br label %6
6: ; preds = %24, %2
%7 = load i32, i32* %5
%8 = load i32, i32* %4
%9 = icmp slt i32 %7, %8
br i1 %9, label %10, label %27
10: ; preds = %6
%11 = load i8*, i8** %3
%12 = load i32, i32* %5
%13 = sext i32 %12 to i64
%14 = getelementptr inbounds i8, i8* %11, i64 %13
%15 = load i8, i8* %14
%16 = zext i8 %15 to i32
%17 = call i32 (...) @rand()
%18 = srem i32 %17, 256
%19 = icmp ne i32 %16, %18
br i1 %19, label %20, label %23
20: ; preds = %10
%21 = call i32 @printf(i8* getelementptr inbounds ([74 x i8], [74 x i8]* @.str, i64 0, i64 0))
%22 = call i32 (...) @exit_failure()
br label %23
23: ; preds = %20, %10
br label %24
24: ; preds = %23
%25 = load i32, i32* %5
%26 = add nsw i32 %25, 1
store i32 %26, i32* %5
br label %6
27: ; preds = %6
ret void
}

LLVM IR (-O2):
@str = [73 x i8] c"ERROR: File did not contain same squence of data as when it was written!\00"
define void @check_chunk(i8* nocapture %0, i32 %1) {
%3 = icmp sgt i32 %1, 0
br i1 %3, label %4, label %20
4: ; preds = %2
%5 = zext i32 %1 to i64
br label %6
6: ; preds = %4, %17
%7 = phi i64 [ 0, %4 ], [ %18, %17 ]
%8 = getelementptr inbounds i8, i8* %0, i64 %7
%9 = load i8, i8* %8
%10 = zext i8 %9 to i32
%11 = tail call i32 (...) @rand()
%12 = srem i32 %11, 256
%13 = icmp eq i32 %12, %10
br i1 %13, label %17, label %14
14: ; preds = %6
%15 = tail call i32 @puts(i8* dereferenceable(1) getelementptr inbounds ([73 x i8], [73 x i8]* @str, i64 0, i64 0))
%16 = tail call i32 (...) @exit_failure()
br label %17
17: ; preds = %6, %14
%18 = add nuw nsw i64 %7, 1
%19 = icmp eq i64 %18, %5
br i1 %19, label %20, label %6
20: ; preds = %17, %2
ret void
}