const char *filetypestr(int filetype) {
  switch (filetype) {
  case 1:
    return ("GRIB");
    break;
  case 2:
    return ("GRIB2");
    break;
  case 3:
    return ("netCDF");
    break;
  case 4:
    return ("netCDF2");
    break;
  case 5:
    return ("netCDF4");
    break;
  case 6:
    return ("netCDF4 classic");
    break;
  case 7:
    return ("SERVICE");
    break;
  case 8:
    return ("EXTRA");
    break;
  case 9:
    return ("IEG");
    break;
  default:
    return ("");
  }
}


x86 assembly (clang, -O0):
<filetypestr>:
push   %rbp
mov    %rsp,%rbp
mov    %edi,-0xc(%rbp)
mov    -0xc(%rbp),%eax
add    $0xffffffff,%eax
mov    %eax,%ecx
mov    %rcx,-0x18(%rbp)
sub    $0x8,%eax
ja     11c0 <filetypestr+0xc0>
mov    -0x18(%rbp),%rax
lea    0xed9(%rip),%rcx
movslq (%rcx,%rax,4),%rax
add    %rcx,%rax
jmp    *%rax
lea    0xeed(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    11cb <filetypestr+0xcb>
lea    0xee2(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    11cb <filetypestr+0xcb>
lea    0xed8(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    11cb <filetypestr+0xcb>
lea    0xecf(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    11cb <filetypestr+0xcb>
lea    0xec7(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    11cb <filetypestr+0xcb>
lea    0xebf(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    11cb <filetypestr+0xcb>
lea    0xebf(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    11cb <filetypestr+0xcb>
lea    0xeb7(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    11cb <filetypestr+0xcb>
lea    0xead(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    11cb <filetypestr+0xcb>
lea    0xe67(%rip),%rax
mov    %rax,-0x8(%rbp)
mov    -0x8(%rbp),%rax
pop    %rbp
ret

x86 assembly (clang, -O2):
<filetypestr>:
add    $0xffffffff,%edi
cmp    $0x8,%edi
ja     111a <filetypestr+0x1a>
movslq %edi,%rax
lea    0xf32(%rip),%rcx
movslq (%rcx,%rax,4),%rax
add    %rcx,%rax
ret
lea    0xee9(%rip),%rax
ret

LLVM IR (-O0):
@.str = [5 x i8] c"GRIB\00"
@.str.1 = [6 x i8] c"GRIB2\00"
@.str.2 = [7 x i8] c"netCDF\00"
@.str.3 = [8 x i8] c"netCDF2\00"
@.str.4 = [8 x i8] c"netCDF4\00"
@.str.5 = [16 x i8] c"netCDF4 classic\00"
@.str.6 = [8 x i8] c"SERVICE\00"
@.str.7 = [6 x i8] c"EXTRA\00"
@.str.8 = [4 x i8] c"IEG\00"
@.str.9 = [1 x i8] zeroinitializer
define i8* @filetypestr(i32 %0) {
%2 = alloca i8*
%3 = alloca i32
store i32 %0, i32* %3
%4 = load i32, i32* %3
switch i32 %4, label %14 [
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
]
5: ; preds = %1
store i8* getelementptr inbounds ([5 x i8], [5 x i8]* @.str, i64 0, i64 0), i8** %2
br label %15
6: ; preds = %1
store i8* getelementptr inbounds ([6 x i8], [6 x i8]* @.str.1, i64 0, i64 0), i8** %2
br label %15
7: ; preds = %1
store i8* getelementptr inbounds ([7 x i8], [7 x i8]* @.str.2, i64 0, i64 0), i8** %2
br label %15
8: ; preds = %1
store i8* getelementptr inbounds ([8 x i8], [8 x i8]* @.str.3, i64 0, i64 0), i8** %2
br label %15
9: ; preds = %1
store i8* getelementptr inbounds ([8 x i8], [8 x i8]* @.str.4, i64 0, i64 0), i8** %2
br label %15
10: ; preds = %1
store i8* getelementptr inbounds ([16 x i8], [16 x i8]* @.str.5, i64 0, i64 0), i8** %2
br label %15
11: ; preds = %1
store i8* getelementptr inbounds ([8 x i8], [8 x i8]* @.str.6, i64 0, i64 0), i8** %2
br label %15
12: ; preds = %1
store i8* getelementptr inbounds ([6 x i8], [6 x i8]* @.str.7, i64 0, i64 0), i8** %2
br label %15
13: ; preds = %1
store i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str.8, i64 0, i64 0), i8** %2
br label %15
14: ; preds = %1
store i8* getelementptr inbounds ([1 x i8], [1 x i8]* @.str.9, i64 0, i64 0), i8** %2
br label %15
15: ; preds = %14, %13, %12, %11, %10, %9, %8, %7, %6, %5
%16 = load i8*, i8** %2
ret i8* %16
}

LLVM IR (-O2):
@.str = [5 x i8] c"GRIB\00"
@.str.1 = [6 x i8] c"GRIB2\00"
@.str.2 = [7 x i8] c"netCDF\00"
@.str.3 = [8 x i8] c"netCDF2\00"
@.str.4 = [8 x i8] c"netCDF4\00"
@.str.5 = [16 x i8] c"netCDF4 classic\00"
@.str.6 = [8 x i8] c"SERVICE\00"
@.str.7 = [6 x i8] c"EXTRA\00"
@.str.8 = [4 x i8] c"IEG\00"
@.str.9 = [1 x i8] zeroinitializer
@reltable.filetypestr = [9 x i32] [i32 trunc (i64 sub (i64 ptrtoint ([5 x i8]* @.str to i64), i64 ptrtoint ([9 x i32]* @reltable.filetypestr to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([6 x i8]* @.str.1 to i64), i64 ptrtoint ([9 x i32]* @reltable.filetypestr to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([7 x i8]* @.str.2 to i64), i64 ptrtoint ([9 x i32]* @reltable.filetypestr to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([8 x i8]* @.str.3 to i64), i64 ptrtoint ([9 x i32]* @reltable.filetypestr to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([8 x i8]* @.str.4 to i64), i64 ptrtoint ([9 x i32]* @reltable.filetypestr to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([16 x i8]* @.str.5 to i64), i64 ptrtoint ([9 x i32]* @reltable.filetypestr to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([8 x i8]* @.str.6 to i64), i64 ptrtoint ([9 x i32]* @reltable.filetypestr to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([6 x i8]* @.str.7 to i64), i64 ptrtoint ([9 x i32]* @reltable.filetypestr to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([4 x i8]* @.str.8 to i64), i64 ptrtoint ([9 x i32]* @reltable.filetypestr to i64)) to i32)]
define i8* @filetypestr(i32 %0) {
%2 = add i32 %0, -1
%3 = icmp ult i32 %2, 9
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 ([9 x i32]* @reltable.filetypestr to i8*), i64 %6)
br label %8
8: ; preds = %1, %4
%9 = phi i8* [ %7, %4 ], [ getelementptr inbounds ([1 x i8], [1 x i8]* @.str.9, i64 0, i64 0), %1 ]
ret i8* %9
}