const char *chan_name(int cnum) {
  switch (cnum) {
  case 0:
    return "______";
    break;
  case 1:
    return "VIS006";
    break;
  case 2:
    return "VIS008";
    break;
  case 3:
    return "IR_016";
    break;
  case 4:
    return "IR_039";
    break;
  case 5:
    return "WV_062";
    break;
  case 6:
    return "WV_073";
    break;
  case 7:
    return "IR_087";
    break;
  case 8:
    return "IR_097";
    break;
  case 9:
    return "IR_108";
    break;
  case 10:
    return "IR_120";
    break;
  case 11:
    return "IR_134";
    break;
  case 12:
    return "HRV___";
    break;
  case 13:
    return "______";
    break;
  default:
    return "______";
    break;
  }
}


x86 assembly (clang, -O0):
<chan_name>:
push   %rbp
mov    %rsp,%rbp
mov    %edi,-0xc(%rbp)
mov    -0xc(%rbp),%eax
mov    %rax,-0x18(%rbp)
sub    $0xd,%rax
ja     120c <chan_name+0x10c>
mov    -0x18(%rbp),%rax
lea    0xedd(%rip),%rcx
movslq (%rcx,%rax,4),%rax
add    %rcx,%rax
jmp    *%rax
lea    0xf05(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    1217 <chan_name+0x117>
lea    0xefc(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    1217 <chan_name+0x117>
lea    0xef3(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    1217 <chan_name+0x117>
lea    0xeea(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    1217 <chan_name+0x117>
lea    0xee1(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    1217 <chan_name+0x117>
lea    0xed8(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    1217 <chan_name+0x117>
lea    0xecf(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    1217 <chan_name+0x117>
lea    0xec6(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    1217 <chan_name+0x117>
lea    0xebd(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    1217 <chan_name+0x117>
lea    0xeb4(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    1217 <chan_name+0x117>
lea    0xeab(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    1217 <chan_name+0x117>
lea    0xea2(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    1217 <chan_name+0x117>
lea    0xe99(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    1217 <chan_name+0x117>
lea    0xe35(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    1217 <chan_name+0x117>
lea    0xe25(%rip),%rax
mov    %rax,-0x8(%rbp)
mov    -0x8(%rbp),%rax
pop    %rbp
ret

x86 assembly (clang, -O2):
<chan_name>:
add    $0xffffffff,%edi
cmp    $0xb,%edi
ja     111a <chan_name+0x1a>
movslq %edi,%rax
lea    0xf4a(%rip),%rcx
movslq (%rcx,%rax,4),%rax
add    %rcx,%rax
ret
lea    0xedf(%rip),%rax
ret

LLVM IR (-O0):
@.str = [7 x i8] c"______\00"
@.str.1 = [7 x i8] c"VIS006\00"
@.str.2 = [7 x i8] c"VIS008\00"
@.str.3 = [7 x i8] c"IR_016\00"
@.str.4 = [7 x i8] c"IR_039\00"
@.str.5 = [7 x i8] c"WV_062\00"
@.str.6 = [7 x i8] c"WV_073\00"
@.str.7 = [7 x i8] c"IR_087\00"
@.str.8 = [7 x i8] c"IR_097\00"
@.str.9 = [7 x i8] c"IR_108\00"
@.str.10 = [7 x i8] c"IR_120\00"
@.str.11 = [7 x i8] c"IR_134\00"
@.str.12 = [7 x i8] c"HRV___\00"
define i8* @chan_name(i32 %0) {
%2 = alloca i8*
%3 = alloca i32
store i32 %0, i32* %3
%4 = load i32, i32* %3
switch i32 %4, label %19 [
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 13, label %18
]
5: ; preds = %1
store i8* getelementptr inbounds ([7 x i8], [7 x i8]* @.str, i64 0, i64 0), i8** %2
br label %20
6: ; preds = %1
store i8* getelementptr inbounds ([7 x i8], [7 x i8]* @.str.1, i64 0, i64 0), i8** %2
br label %20
7: ; preds = %1
store i8* getelementptr inbounds ([7 x i8], [7 x i8]* @.str.2, i64 0, i64 0), i8** %2
br label %20
8: ; preds = %1
store i8* getelementptr inbounds ([7 x i8], [7 x i8]* @.str.3, i64 0, i64 0), i8** %2
br label %20
9: ; preds = %1
store i8* getelementptr inbounds ([7 x i8], [7 x i8]* @.str.4, i64 0, i64 0), i8** %2
br label %20
10: ; preds = %1
store i8* getelementptr inbounds ([7 x i8], [7 x i8]* @.str.5, i64 0, i64 0), i8** %2
br label %20
11: ; preds = %1
store i8* getelementptr inbounds ([7 x i8], [7 x i8]* @.str.6, i64 0, i64 0), i8** %2
br label %20
12: ; preds = %1
store i8* getelementptr inbounds ([7 x i8], [7 x i8]* @.str.7, i64 0, i64 0), i8** %2
br label %20
13: ; preds = %1
store i8* getelementptr inbounds ([7 x i8], [7 x i8]* @.str.8, i64 0, i64 0), i8** %2
br label %20
14: ; preds = %1
store i8* getelementptr inbounds ([7 x i8], [7 x i8]* @.str.9, i64 0, i64 0), i8** %2
br label %20
15: ; preds = %1
store i8* getelementptr inbounds ([7 x i8], [7 x i8]* @.str.10, i64 0, i64 0), i8** %2
br label %20
16: ; preds = %1
store i8* getelementptr inbounds ([7 x i8], [7 x i8]* @.str.11, i64 0, i64 0), i8** %2
br label %20
17: ; preds = %1
store i8* getelementptr inbounds ([7 x i8], [7 x i8]* @.str.12, i64 0, i64 0), i8** %2
br label %20
18: ; preds = %1
store i8* getelementptr inbounds ([7 x i8], [7 x i8]* @.str, i64 0, i64 0), i8** %2
br label %20
19: ; preds = %1
store i8* getelementptr inbounds ([7 x i8], [7 x i8]* @.str, i64 0, i64 0), i8** %2
br label %20
20: ; preds = %19, %18, %17, %16, %15, %14, %13, %12, %11, %10, %9, %8, %7, %6, %5
%21 = load i8*, i8** %2
ret i8* %21
}

LLVM IR (-O2):
@.str = [7 x i8] c"______\00"
@.str.1 = [7 x i8] c"VIS006\00"
@.str.2 = [7 x i8] c"VIS008\00"
@.str.3 = [7 x i8] c"IR_016\00"
@.str.4 = [7 x i8] c"IR_039\00"
@.str.5 = [7 x i8] c"WV_062\00"
@.str.6 = [7 x i8] c"WV_073\00"
@.str.7 = [7 x i8] c"IR_087\00"
@.str.8 = [7 x i8] c"IR_097\00"
@.str.9 = [7 x i8] c"IR_108\00"
@.str.10 = [7 x i8] c"IR_120\00"
@.str.11 = [7 x i8] c"IR_134\00"
@.str.12 = [7 x i8] c"HRV___\00"
@reltable.chan_name = [12 x i32] [i32 trunc (i64 sub (i64 ptrtoint ([7 x i8]* @.str.1 to i64), i64 ptrtoint ([12 x i32]* @reltable.chan_name to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([7 x i8]* @.str.2 to i64), i64 ptrtoint ([12 x i32]* @reltable.chan_name to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([7 x i8]* @.str.3 to i64), i64 ptrtoint ([12 x i32]* @reltable.chan_name to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([7 x i8]* @.str.4 to i64), i64 ptrtoint ([12 x i32]* @reltable.chan_name to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([7 x i8]* @.str.5 to i64), i64 ptrtoint ([12 x i32]* @reltable.chan_name to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([7 x i8]* @.str.6 to i64), i64 ptrtoint ([12 x i32]* @reltable.chan_name to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([7 x i8]* @.str.7 to i64), i64 ptrtoint ([12 x i32]* @reltable.chan_name to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([7 x i8]* @.str.8 to i64), i64 ptrtoint ([12 x i32]* @reltable.chan_name to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([7 x i8]* @.str.9 to i64), i64 ptrtoint ([12 x i32]* @reltable.chan_name to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([7 x i8]* @.str.10 to i64), i64 ptrtoint ([12 x i32]* @reltable.chan_name to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([7 x i8]* @.str.11 to i64), i64 ptrtoint ([12 x i32]* @reltable.chan_name to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([7 x i8]* @.str.12 to i64), i64 ptrtoint ([12 x i32]* @reltable.chan_name to i64)) to i32)]
define i8* @chan_name(i32 %0) {
%2 = add i32 %0, -1
%3 = icmp ult i32 %2, 12
br i1 %3, label %4, label %8
4: ; preds = %1
%5 = sext i32 %2 to i64
%6 = shl i64 %5, 2
%7 = call i8* @llvm.load.relative.i64(i8* bitcast ([12 x i32]* @reltable.chan_name to i8*), i64 %6)
br label %8
8: ; preds = %4, %1
%9 = phi i8* [ getelementptr inbounds ([7 x i8], [7 x i8]* @.str, i64 0, i64 0), %1 ], [ %7, %4 ]
ret i8* %9
}