int fact4(int n) {
  switch (n) {
  case 0:
  case 1:
    return 1;
  case 2:
    return 1 * 2;
  case 3:
    return 1 * 2 * 3;
  case 4:
    return 1 * 2 * 3 * 4;
  case 5:
    return 1 * 2 * 3 * 4 * 5;
  case 6:
    return 1 * 2 * 3 * 4 * 5 * 6;
  case 7:
    return 1 * 2 * 3 * 4 * 5 * 6 * 7;
  case 8:
    return 1 * 2 * 3 * 4 * 5 * 6 * 7 * 8;
  case 9:
    return 1 * 2 * 3 * 4 * 5 * 6 * 7 * 8 * 9;
  case 10:
    return 1 * 2 * 3 * 4 * 5 * 6 * 7 * 8 * 9 * 10;
  case 11:
    return 1 * 2 * 3 * 4 * 5 * 6 * 7 * 8 * 9 * 10 * 11;
  case 12:
    return 1 * 2 * 3 * 4 * 5 * 6 * 7 * 8 * 9 * 10 * 11 * 12;
  case 13:
    return 1 * 2 * 3 * 4 * 5 * 6 * 7 * 8 * 9 * 10 * 11 * 12 * 13;
  case 14:
    return 1 * 2 * 3 * 4 * 5 * 6 * 7 * 8 * 9 * 10 * 11 * 12 * 13 * 14;
  case 15:
    return 1 * 2 * 3 * 4 * 5 * 6 * 7 * 8 * 9 * 10 * 11 * 12 * 13 * 14 * 15;
  case 16:
    return 1 * 2 * 3 * 4 * 5 * 6 * 7 * 8 * 9 * 10 * 11 * 12 * 13 * 14 * 15 * 16;
  default:
    return -1;
  }
}


x86 assembly (clang, -O0):
<fact4>:
push   %rbp
mov    %rsp,%rbp
mov    %edi,-0x8(%rbp)
mov    -0x8(%rbp),%eax
mov    %rax,-0x10(%rbp)
sub    $0x10,%rax
ja     11ec <fact4+0xec>
mov    -0x10(%rbp),%rax
lea    0xedd(%rip),%rcx
movslq (%rcx,%rax,4),%rax
add    %rcx,%rax
jmp    *%rax
movl   $0x1,-0x4(%rbp)
jmp    11f3 <fact4+0xf3>
movl   $0x2,-0x4(%rbp)
jmp    11f3 <fact4+0xf3>
movl   $0x6,-0x4(%rbp)
jmp    11f3 <fact4+0xf3>
movl   $0x18,-0x4(%rbp)
jmp    11f3 <fact4+0xf3>
movl   $0x78,-0x4(%rbp)
jmp    11f3 <fact4+0xf3>
movl   $0x2d0,-0x4(%rbp)
jmp    11f3 <fact4+0xf3>
movl   $0x13b0,-0x4(%rbp)
jmp    11f3 <fact4+0xf3>
movl   $0x9d80,-0x4(%rbp)
jmp    11f3 <fact4+0xf3>
movl   $0x58980,-0x4(%rbp)
jmp    11f3 <fact4+0xf3>
movl   $0x375f00,-0x4(%rbp)
jmp    11f3 <fact4+0xf3>
movl   $0x2611500,-0x4(%rbp)
jmp    11f3 <fact4+0xf3>
movl   $0x1c8cfc00,-0x4(%rbp)
jmp    11f3 <fact4+0xf3>
movl   $0x7328cc00,-0x4(%rbp)
jmp    11f3 <fact4+0xf3>
movl   $0x4c3b2800,-0x4(%rbp)
jmp    11f3 <fact4+0xf3>
movl   $0x77775800,-0x4(%rbp)
jmp    11f3 <fact4+0xf3>
movl   $0x77758000,-0x4(%rbp)
jmp    11f3 <fact4+0xf3>
movl   $0xffffffff,-0x4(%rbp)
mov    -0x4(%rbp),%eax
pop    %rbp
ret

x86 assembly (clang, -O2):
<fact4>:
mov    $0xffffffff,%eax
cmp    $0x10,%edi
ja     1117 <fact4+0x17>
movslq %edi,%rax
lea    0xeec(%rip),%rcx
mov    (%rcx,%rax,4),%eax
ret

LLVM IR (-O0):
define i32 @fact4(i32 %0) {
%2 = alloca i32
%3 = alloca i32
store i32 %0, i32* %3
%4 = load i32, i32* %3
switch i32 %4, label %21 [
i32 0, label %5
i32 1, label %5
i32 2, label %6
i32 3, label %7
i32 4, label %8
i32 5, label %9
i32 6, label %10
i32 7, label %11
i32 8, label %12
i32 9, label %13
i32 10, label %14
i32 11, label %15
i32 12, label %16
i32 13, label %17
i32 14, label %18
i32 15, label %19
i32 16, label %20
]
5: ; preds = %1, %1
store i32 1, i32* %2
br label %22
6: ; preds = %1
store i32 2, i32* %2
br label %22
7: ; preds = %1
store i32 6, i32* %2
br label %22
8: ; preds = %1
store i32 24, i32* %2
br label %22
9: ; preds = %1
store i32 120, i32* %2
br label %22
10: ; preds = %1
store i32 720, i32* %2
br label %22
11: ; preds = %1
store i32 5040, i32* %2
br label %22
12: ; preds = %1
store i32 40320, i32* %2
br label %22
13: ; preds = %1
store i32 362880, i32* %2
br label %22
14: ; preds = %1
store i32 3628800, i32* %2
br label %22
15: ; preds = %1
store i32 39916800, i32* %2
br label %22
16: ; preds = %1
store i32 479001600, i32* %2
br label %22
17: ; preds = %1
store i32 1932053504, i32* %2
br label %22
18: ; preds = %1
store i32 1278945280, i32* %2
br label %22
19: ; preds = %1
store i32 2004310016, i32* %2
br label %22
20: ; preds = %1
store i32 2004189184, i32* %2
br label %22
21: ; preds = %1
store i32 -1, i32* %2
br label %22
22: ; preds = %21, %20, %19, %18, %17, %16, %15, %14, %13, %12, %11, %10, %9, %8, %7, %6, %5
%23 = load i32, i32* %2
ret i32 %23
}

LLVM IR (-O2):
@switch.table.fact4 = [17 x i32] [i32 1, i32 1, i32 2, i32 6, i32 24, i32 120, i32 720, i32 5040, i32 40320, i32 362880, i32 3628800, i32 39916800, i32 479001600, i32 1932053504, i32 1278945280, i32 2004310016, i32 2004189184]
define i32 @fact4(i32 %0) {
%2 = icmp ult i32 %0, 17
br i1 %2, label %3, label %7
3: ; preds = %1
%4 = sext i32 %0 to i64
%5 = getelementptr inbounds [17 x i32], [17 x i32]* @switch.table.fact4, i64 0, i64 %4
%6 = load i32, i32* %5
br label %7
7: ; preds = %1, %3
%8 = phi i32 [ %6, %3 ], [ -1, %1 ]
ret i32 %8
}