#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 */
unsigned long bad_user_access_length();
unsigned long __get_user(const void *y, int size) {
  switch (size) {
  case 1:
    return *(unsigned char *)y;
  case 2:
    return *(unsigned short *)y;
  case 4:
    return *(unsigned long *)y;
  default:
    return bad_user_access_length();
  }
}


x86 assembly (clang, -O0):
<__get_user>:
push   %rbp
mov    %rsp,%rbp
sub    $0x20,%rsp
mov    %rdi,-0x10(%rbp)
mov    %esi,-0x14(%rbp)
mov    -0x14(%rbp),%eax
mov    %eax,-0x18(%rbp)
sub    $0x1,%eax
je     1155 <__get_user+0x45>
jmp    1133 <__get_user+0x23>
mov    -0x18(%rbp),%eax
sub    $0x2,%eax
je     1165 <__get_user+0x55>
jmp    1144 <__get_user+0x34>
mov    -0x18(%rbp),%eax
sub    $0x4,%eax
je     1175 <__get_user+0x65>
jmp    1185 <__get_user+0x75>
mov    -0x10(%rbp),%rax
movzbl (%rax),%eax
mov    %rax,-0x8(%rbp)
jmp    1190 <__get_user+0x80>
mov    -0x10(%rbp),%rax
movzwl (%rax),%eax
mov    %rax,-0x8(%rbp)
jmp    1190 <__get_user+0x80>
mov    -0x10(%rbp),%rax
mov    (%rax),%rax
mov    %rax,-0x8(%rbp)
jmp    1190 <__get_user+0x80>
mov    $0x0,%al
call   1030 <bad_user_access_length@plt>
mov    %rax,-0x8(%rbp)
mov    -0x8(%rbp),%rax
add    $0x20,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<__get_user>:
cmp    $0x4,%esi
je     1123 <__get_user+0x13>
cmp    $0x2,%esi
je     1127 <__get_user+0x17>
cmp    $0x1,%esi
jne    112b <__get_user+0x1b>
movzbl (%rdi),%eax
ret
mov    (%rdi),%rax
ret
movzwl (%rdi),%eax
ret
xor    %eax,%eax
jmp    1030 <bad_user_access_length@plt>

LLVM IR (-O0):
define i64 @__get_user(i8* %0, i32 %1) {
%3 = alloca i64
%4 = alloca i8*
%5 = alloca i32
store i8* %0, i8** %4
store i32 %1, i32* %5
%6 = load i32, i32* %5
switch i32 %6, label %20 [
i32 1, label %7
i32 2, label %11
i32 4, label %16
]
7: ; preds = %2
%8 = load i8*, i8** %4
%9 = load i8, i8* %8
%10 = zext i8 %9 to i64
store i64 %10, i64* %3
br label %22
11: ; preds = %2
%12 = load i8*, i8** %4
%13 = bitcast i8* %12 to i16*
%14 = load i16, i16* %13
%15 = zext i16 %14 to i64
store i64 %15, i64* %3
br label %22
16: ; preds = %2
%17 = load i8*, i8** %4
%18 = bitcast i8* %17 to i64*
%19 = load i64, i64* %18
store i64 %19, i64* %3
br label %22
20: ; preds = %2
%21 = call i64 (...) @bad_user_access_length()
store i64 %21, i64* %3
br label %22
22: ; preds = %20, %16, %11, %7
%23 = load i64, i64* %3
ret i64 %23
}

LLVM IR (-O2):
define i64 @__get_user(i8* nocapture %0, i32 %1) {
switch i32 %1, label %13 [
i32 1, label %3
i32 2, label %6
i32 4, label %10
]
3: ; preds = %2
%4 = load i8, i8* %0
%5 = zext i8 %4 to i64
br label %15
6: ; preds = %2
%7 = bitcast i8* %0 to i16*
%8 = load i16, i16* %7
%9 = zext i16 %8 to i64
br label %15
10: ; preds = %2
%11 = bitcast i8* %0 to i64*
%12 = load i64, i64* %11
br label %15
13: ; preds = %2
%14 = tail call i64 (...) @bad_user_access_length()
br label %15
15: ; preds = %13, %10, %6, %3
%16 = phi i64 [ %14, %13 ], [ %12, %10 ], [ %9, %6 ], [ %5, %3 ]
ret i64 %16
}