const char *mode_name(int mode) {
  switch (mode) {
  case 0x00:
    return "No Change";
  case 0x01:
    return "High Impedance";
  case 0x02:
    return "Digital Input";
  case 0x03:
    return "Digital Output";
  case 0x04:
    return "Analog Input";
  case 0x05:
    return "Analog Output";
  case 0x06:
    return "PWM";
  case 0x07:
    return "Servo";
  case 0x08:
    return "UART Transmit";
  case 0x09:
    return "UART Receive";
  case 0x0A:
    return "SPI MOSI";
  case 0x0B:
    return "SPI MISO";
  case 0x0C:
    return "SPI SCK";
  case 0x0E:
    return "Counter Input INT";
  case 0x0F:
    return "Counter Input DIR";
  case 0x10:
    return "Counter Input HOME";
  case 0x11:
    return "Counter Output INT";
  case 0x12:
    return "Counter Output DIR";
  case 0x13:
    return "Counter Output HOME";
  case 0x14:
    return "DC Motor VEL";
  case 0x15:
    return "DC Motor DIR";
  case 0x16:
    return "PPM Input";
  default:
    return "UNKNOWN";
  }
}


x86 assembly (clang, -O0):
<mode_name>:
push   %rbp
mov    %rsp,%rbp
mov    %edi,-0xc(%rbp)
mov    -0xc(%rbp),%eax
mov    %rax,-0x18(%rbp)
sub    $0x16,%rax
ja     128c <mode_name+0x18c>
mov    -0x18(%rbp),%rax
lea    0xedd(%rip),%rcx
movslq (%rcx,%rax,4),%rax
add    %rcx,%rax
jmp    *%rax
lea    0xf29(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    1297 <mode_name+0x197>
lea    0xf23(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    1297 <mode_name+0x197>
lea    0xf22(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    1297 <mode_name+0x197>
lea    0xf20(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    1297 <mode_name+0x197>
lea    0xf1f(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    1297 <mode_name+0x197>
lea    0xf1c(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    1297 <mode_name+0x197>
lea    0xf1a(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    1297 <mode_name+0x197>
lea    0xf0e(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    1297 <mode_name+0x197>
lea    0xf04(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    1297 <mode_name+0x197>
lea    0xf02(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    1297 <mode_name+0x197>
lea    0xeff(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    1297 <mode_name+0x197>
lea    0xef8(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    1297 <mode_name+0x197>
lea    0xef1(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    1297 <mode_name+0x197>
lea    0xee9(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    1297 <mode_name+0x197>
lea    0xeeb(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    1297 <mode_name+0x197>
lea    0xeed(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    1297 <mode_name+0x197>
lea    0xef0(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    1297 <mode_name+0x197>
lea    0xef3(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    1297 <mode_name+0x197>
lea    0xef6(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    1297 <mode_name+0x197>
lea    0xefa(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    1297 <mode_name+0x197>
lea    0xef7(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    1297 <mode_name+0x197>
lea    0xef4(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    1297 <mode_name+0x197>
lea    0xeee(%rip),%rax
mov    %rax,-0x8(%rbp)
mov    -0x8(%rbp),%rax
pop    %rbp
ret

x86 assembly (clang, -O2):
<mode_name>:
cmp    $0x16,%edi
ja     1117 <mode_name+0x17>
movslq %edi,%rax
lea    0x1021(%rip),%rcx
movslq (%rcx,%rax,4),%rax
add    %rcx,%rax
ret
lea    0x1007(%rip),%rax
ret

LLVM IR (-O0):
@.str = [10 x i8] c"No Change\00"
@.str.1 = [15 x i8] c"High Impedance\00"
@.str.2 = [14 x i8] c"Digital Input\00"
@.str.3 = [15 x i8] c"Digital Output\00"
@.str.4 = [13 x i8] c"Analog Input\00"
@.str.5 = [14 x i8] c"Analog Output\00"
@.str.6 = [4 x i8] c"PWM\00"
@.str.7 = [6 x i8] c"Servo\00"
@.str.8 = [14 x i8] c"UART Transmit\00"
@.str.9 = [13 x i8] c"UART Receive\00"
@.str.10 = [9 x i8] c"SPI MOSI\00"
@.str.11 = [9 x i8] c"SPI MISO\00"
@.str.12 = [8 x i8] c"SPI SCK\00"
@.str.13 = [18 x i8] c"Counter Input INT\00"
@.str.14 = [18 x i8] c"Counter Input DIR\00"
@.str.15 = [19 x i8] c"Counter Input HOME\00"
@.str.16 = [19 x i8] c"Counter Output INT\00"
@.str.17 = [19 x i8] c"Counter Output DIR\00"
@.str.18 = [20 x i8] c"Counter Output HOME\00"
@.str.19 = [13 x i8] c"DC Motor VEL\00"
@.str.20 = [13 x i8] c"DC Motor DIR\00"
@.str.21 = [10 x i8] c"PPM Input\00"
@.str.22 = [8 x i8] c"UNKNOWN\00"
define i8* @mode_name(i32 %0) {
%2 = alloca i8*
%3 = alloca i32
store i32 %0, i32* %3
%4 = load i32, i32* %3
switch i32 %4, label %27 [
i32 0, label %5
i32 1, label %6
i32 2, label %7
i32 3, label %8
i32 4, label %9
i32 5, label %10
i32 6, label %11
i32 7, label %12
i32 8, label %13
i32 9, label %14
i32 10, label %15
i32 11, label %16
i32 12, label %17
i32 14, label %18
i32 15, label %19
i32 16, label %20
i32 17, label %21
i32 18, label %22
i32 19, label %23
i32 20, label %24
i32 21, label %25
i32 22, label %26
]
5: ; preds = %1
store i8* getelementptr inbounds ([10 x i8], [10 x i8]* @.str, i64 0, i64 0), i8** %2
br label %28
6: ; preds = %1
store i8* getelementptr inbounds ([15 x i8], [15 x i8]* @.str.1, i64 0, i64 0), i8** %2
br label %28
7: ; preds = %1
store i8* getelementptr inbounds ([14 x i8], [14 x i8]* @.str.2, i64 0, i64 0), i8** %2
br label %28
8: ; preds = %1
store i8* getelementptr inbounds ([15 x i8], [15 x i8]* @.str.3, i64 0, i64 0), i8** %2
br label %28
9: ; preds = %1
store i8* getelementptr inbounds ([13 x i8], [13 x i8]* @.str.4, i64 0, i64 0), i8** %2
br label %28
10: ; preds = %1
store i8* getelementptr inbounds ([14 x i8], [14 x i8]* @.str.5, i64 0, i64 0), i8** %2
br label %28
11: ; preds = %1
store i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str.6, i64 0, i64 0), i8** %2
br label %28
12: ; preds = %1
store i8* getelementptr inbounds ([6 x i8], [6 x i8]* @.str.7, i64 0, i64 0), i8** %2
br label %28
13: ; preds = %1
store i8* getelementptr inbounds ([14 x i8], [14 x i8]* @.str.8, i64 0, i64 0), i8** %2
br label %28
14: ; preds = %1
store i8* getelementptr inbounds ([13 x i8], [13 x i8]* @.str.9, i64 0, i64 0), i8** %2
br label %28
15: ; preds = %1
store i8* getelementptr inbounds ([9 x i8], [9 x i8]* @.str.10, i64 0, i64 0), i8** %2
br label %28
16: ; preds = %1
store i8* getelementptr inbounds ([9 x i8], [9 x i8]* @.str.11, i64 0, i64 0), i8** %2
br label %28
17: ; preds = %1
store i8* getelementptr inbounds ([8 x i8], [8 x i8]* @.str.12, i64 0, i64 0), i8** %2
br label %28
18: ; preds = %1
store i8* getelementptr inbounds ([18 x i8], [18 x i8]* @.str.13, i64 0, i64 0), i8** %2
br label %28
19: ; preds = %1
store i8* getelementptr inbounds ([18 x i8], [18 x i8]* @.str.14, i64 0, i64 0), i8** %2
br label %28
20: ; preds = %1
store i8* getelementptr inbounds ([19 x i8], [19 x i8]* @.str.15, i64 0, i64 0), i8** %2
br label %28
21: ; preds = %1
store i8* getelementptr inbounds ([19 x i8], [19 x i8]* @.str.16, i64 0, i64 0), i8** %2
br label %28
22: ; preds = %1
store i8* getelementptr inbounds ([19 x i8], [19 x i8]* @.str.17, i64 0, i64 0), i8** %2
br label %28
23: ; preds = %1
store i8* getelementptr inbounds ([20 x i8], [20 x i8]* @.str.18, i64 0, i64 0), i8** %2
br label %28
24: ; preds = %1
store i8* getelementptr inbounds ([13 x i8], [13 x i8]* @.str.19, i64 0, i64 0), i8** %2
br label %28
25: ; preds = %1
store i8* getelementptr inbounds ([13 x i8], [13 x i8]* @.str.20, i64 0, i64 0), i8** %2
br label %28
26: ; preds = %1
store i8* getelementptr inbounds ([10 x i8], [10 x i8]* @.str.21, i64 0, i64 0), i8** %2
br label %28
27: ; preds = %1
store i8* getelementptr inbounds ([8 x i8], [8 x i8]* @.str.22, i64 0, i64 0), i8** %2
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, %6, %5
%29 = load i8*, i8** %2
ret i8* %29
}

LLVM IR (-O2):
@.str = [10 x i8] c"No Change\00"
@.str.1 = [15 x i8] c"High Impedance\00"
@.str.2 = [14 x i8] c"Digital Input\00"
@.str.3 = [15 x i8] c"Digital Output\00"
@.str.4 = [13 x i8] c"Analog Input\00"
@.str.5 = [14 x i8] c"Analog Output\00"
@.str.6 = [4 x i8] c"PWM\00"
@.str.7 = [6 x i8] c"Servo\00"
@.str.8 = [14 x i8] c"UART Transmit\00"
@.str.9 = [13 x i8] c"UART Receive\00"
@.str.10 = [9 x i8] c"SPI MOSI\00"
@.str.11 = [9 x i8] c"SPI MISO\00"
@.str.12 = [8 x i8] c"SPI SCK\00"
@.str.13 = [18 x i8] c"Counter Input INT\00"
@.str.14 = [18 x i8] c"Counter Input DIR\00"
@.str.15 = [19 x i8] c"Counter Input HOME\00"
@.str.16 = [19 x i8] c"Counter Output INT\00"
@.str.17 = [19 x i8] c"Counter Output DIR\00"
@.str.18 = [20 x i8] c"Counter Output HOME\00"
@.str.19 = [13 x i8] c"DC Motor VEL\00"
@.str.20 = [13 x i8] c"DC Motor DIR\00"
@.str.21 = [10 x i8] c"PPM Input\00"
@.str.22 = [8 x i8] c"UNKNOWN\00"
@reltable.mode_name = [23 x i32] [i32 trunc (i64 sub (i64 ptrtoint ([10 x i8]* @.str to i64), i64 ptrtoint ([23 x i32]* @reltable.mode_name to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([15 x i8]* @.str.1 to i64), i64 ptrtoint ([23 x i32]* @reltable.mode_name to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([14 x i8]* @.str.2 to i64), i64 ptrtoint ([23 x i32]* @reltable.mode_name to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([15 x i8]* @.str.3 to i64), i64 ptrtoint ([23 x i32]* @reltable.mode_name to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([13 x i8]* @.str.4 to i64), i64 ptrtoint ([23 x i32]* @reltable.mode_name to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([14 x i8]* @.str.5 to i64), i64 ptrtoint ([23 x i32]* @reltable.mode_name to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([4 x i8]* @.str.6 to i64), i64 ptrtoint ([23 x i32]* @reltable.mode_name to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([6 x i8]* @.str.7 to i64), i64 ptrtoint ([23 x i32]* @reltable.mode_name to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([14 x i8]* @.str.8 to i64), i64 ptrtoint ([23 x i32]* @reltable.mode_name to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([13 x i8]* @.str.9 to i64), i64 ptrtoint ([23 x i32]* @reltable.mode_name to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([9 x i8]* @.str.10 to i64), i64 ptrtoint ([23 x i32]* @reltable.mode_name to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([9 x i8]* @.str.11 to i64), i64 ptrtoint ([23 x i32]* @reltable.mode_name to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([8 x i8]* @.str.12 to i64), i64 ptrtoint ([23 x i32]* @reltable.mode_name to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([8 x i8]* @.str.22 to i64), i64 ptrtoint ([23 x i32]* @reltable.mode_name to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([18 x i8]* @.str.13 to i64), i64 ptrtoint ([23 x i32]* @reltable.mode_name to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([18 x i8]* @.str.14 to i64), i64 ptrtoint ([23 x i32]* @reltable.mode_name to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([19 x i8]* @.str.15 to i64), i64 ptrtoint ([23 x i32]* @reltable.mode_name to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([19 x i8]* @.str.16 to i64), i64 ptrtoint ([23 x i32]* @reltable.mode_name to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([19 x i8]* @.str.17 to i64), i64 ptrtoint ([23 x i32]* @reltable.mode_name to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([20 x i8]* @.str.18 to i64), i64 ptrtoint ([23 x i32]* @reltable.mode_name to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([13 x i8]* @.str.19 to i64), i64 ptrtoint ([23 x i32]* @reltable.mode_name to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([13 x i8]* @.str.20 to i64), i64 ptrtoint ([23 x i32]* @reltable.mode_name to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([10 x i8]* @.str.21 to i64), i64 ptrtoint ([23 x i32]* @reltable.mode_name to i64)) to i32)]
define i8* @mode_name(i32 %0) {
%2 = icmp ult i32 %0, 23
br i1 %2, label %3, label %7
3: ; preds = %1
%4 = sext i32 %0 to i64
%5 = shl i64 %4, 2
%6 = call i8* @llvm.load.relative.i64(i8* bitcast ([23 x i32]* @reltable.mode_name to i8*), i64 %5)
br label %7
7: ; preds = %1, %3
%8 = phi i8* [ %6, %3 ], [ getelementptr inbounds ([8 x i8], [8 x i8]* @.str.22, i64 0, i64 0), %1 ]
ret i8* %8
}