int Getx(char res) {
  int X;
  switch (res & (char)95) {
  case 'L':
    X = 1;
    break;
  case 'I':
    X = 2;
    break;
  case 'V':
    X = 3;
    break;
  case 'M':
    X = 4;
    break;
  case 'F':
    X = 5;
    break;
  case 'Y':
    X = 6;
    break;
  case 'G':
    X = 7;
    break;
  case 'A':
    X = 8;
    break;
  case 'K':
    X = 9;
    break;
  case 'R':
    X = 10;
    break;
  case 'H':
    X = 11;
    break;
  case 'E':
    X = 12;
    break;
  case 'D':
    X = 13;
    break;
  case 'Q':
    X = 14;
    break;
  case 'N':
    X = 15;
    break;
  case 'S':
    X = 16;
    break;
  case 'T':
    X = 17;
    break;
  case 'C':
    X = 18;
    break;
  case 'W':
    X = 19;
    break;
  case 'P':
    X = 20;
    break;
  default:
    X = -1;
    break;
  }
  return X;
}


x86 assembly (clang, -O0):
<Getx>:
push   %rbp
mov    %rsp,%rbp
mov    %dil,%al
mov    %al,-0x1(%rbp)
movzbl -0x1(%rbp),%eax
and    $0x5f,%eax
add    $0xffffffbf,%eax
mov    %eax,%ecx
mov    %rcx,-0x10(%rbp)
sub    $0x18,%eax
ja     1227 <Getx+0x127>
mov    -0x10(%rbp),%rax
lea    0xed2(%rip),%rcx
movslq (%rcx,%rax,4),%rax
add    %rcx,%rax
jmp    *%rax
movl   $0x1,-0x8(%rbp)
jmp    122e <Getx+0x12e>
movl   $0x2,-0x8(%rbp)
jmp    122e <Getx+0x12e>
movl   $0x3,-0x8(%rbp)
jmp    122e <Getx+0x12e>
movl   $0x4,-0x8(%rbp)
jmp    122e <Getx+0x12e>
movl   $0x5,-0x8(%rbp)
jmp    122e <Getx+0x12e>
movl   $0x6,-0x8(%rbp)
jmp    122e <Getx+0x12e>
movl   $0x7,-0x8(%rbp)
jmp    122e <Getx+0x12e>
movl   $0x8,-0x8(%rbp)
jmp    122e <Getx+0x12e>
movl   $0x9,-0x8(%rbp)
jmp    122e <Getx+0x12e>
movl   $0xa,-0x8(%rbp)
jmp    122e <Getx+0x12e>
movl   $0xb,-0x8(%rbp)
jmp    122e <Getx+0x12e>
movl   $0xc,-0x8(%rbp)
jmp    122e <Getx+0x12e>
movl   $0xd,-0x8(%rbp)
jmp    122e <Getx+0x12e>
movl   $0xe,-0x8(%rbp)
jmp    122e <Getx+0x12e>
movl   $0xf,-0x8(%rbp)
jmp    122e <Getx+0x12e>
movl   $0x10,-0x8(%rbp)
jmp    122e <Getx+0x12e>
movl   $0x11,-0x8(%rbp)
jmp    122e <Getx+0x12e>
movl   $0x12,-0x8(%rbp)
jmp    122e <Getx+0x12e>
movl   $0x13,-0x8(%rbp)
jmp    122e <Getx+0x12e>
movl   $0x14,-0x8(%rbp)
jmp    122e <Getx+0x12e>
movl   $0xffffffff,-0x8(%rbp)
mov    -0x8(%rbp),%eax
pop    %rbp
ret

x86 assembly (clang, -O2):
<Getx>:
and    $0x5f,%edi
add    $0xffffffbf,%edi
mov    $0xffffffff,%eax
cmp    $0x18,%edi
ja     111d <Getx+0x1d>
movslq %edi,%rax
lea    0xee6(%rip),%rcx
mov    (%rcx,%rax,4),%eax
ret

LLVM IR (-O0):
define i32 @Getx(i8 signext %0) {
%2 = alloca i8
%3 = alloca i32
store i8 %0, i8* %2
%4 = load i8, i8* %2
%5 = sext i8 %4 to i32
%6 = and i32 %5, 95
switch i32 %6, label %27 [
i32 76, label %7
i32 73, label %8
i32 86, label %9
i32 77, label %10
i32 70, label %11
i32 89, label %12
i32 71, label %13
i32 65, label %14
i32 75, label %15
i32 82, label %16
i32 72, label %17
i32 69, label %18
i32 68, label %19
i32 81, label %20
i32 78, label %21
i32 83, label %22
i32 84, label %23
i32 67, label %24
i32 87, label %25
i32 80, label %26
]
7: ; preds = %1
store i32 1, i32* %3
br label %28
8: ; preds = %1
store i32 2, i32* %3
br label %28
9: ; preds = %1
store i32 3, i32* %3
br label %28
10: ; preds = %1
store i32 4, i32* %3
br label %28
11: ; preds = %1
store i32 5, i32* %3
br label %28
12: ; preds = %1
store i32 6, i32* %3
br label %28
13: ; preds = %1
store i32 7, i32* %3
br label %28
14: ; preds = %1
store i32 8, i32* %3
br label %28
15: ; preds = %1
store i32 9, i32* %3
br label %28
16: ; preds = %1
store i32 10, i32* %3
br label %28
17: ; preds = %1
store i32 11, i32* %3
br label %28
18: ; preds = %1
store i32 12, i32* %3
br label %28
19: ; preds = %1
store i32 13, i32* %3
br label %28
20: ; preds = %1
store i32 14, i32* %3
br label %28
21: ; preds = %1
store i32 15, i32* %3
br label %28
22: ; preds = %1
store i32 16, i32* %3
br label %28
23: ; preds = %1
store i32 17, i32* %3
br label %28
24: ; preds = %1
store i32 18, i32* %3
br label %28
25: ; preds = %1
store i32 19, i32* %3
br label %28
26: ; preds = %1
store i32 20, i32* %3
br label %28
27: ; preds = %1
store i32 -1, i32* %3
br label %28
28: ; preds = %27, %26, %25, %24, %23, %22, %21, %20, %19, %18, %17, %16, %15, %14, %13, %12, %11, %10, %9, %8, %7
%29 = load i32, i32* %3
ret i32 %29
}

LLVM IR (-O2):
@switch.table.Getx = [25 x i32] [i32 8, i32 -1, i32 18, i32 13, i32 12, i32 5, i32 7, i32 11, i32 2, i32 -1, i32 9, i32 1, i32 4, i32 15, i32 -1, i32 20, i32 14, i32 10, i32 16, i32 17, i32 -1, i32 3, i32 19, i32 -1, i32 6]
define i32 @Getx(i8 signext %0) {
%2 = and i8 %0, 95
%3 = zext i8 %2 to i32
%4 = add nsw i32 %3, -65
%5 = icmp ult i32 %4, 25
br i1 %5, label %6, label %10
6: ; preds = %1
%7 = sext i32 %4 to i64
%8 = getelementptr inbounds [25 x i32], [25 x i32]* @switch.table.Getx, i64 0, i64 %7
%9 = load i32, i32* %8
br label %10
10: ; preds = %1, %6
%11 = phi i32 [ %9, %6 ], [ -1, %1 ]
ret i32 %11
}