char *icmp_type(unsigned char id) {
  switch (id) {
  case 0:
    return ("Echo Reply");
  case 3:
    return ("Destination Unreachable");
  case 4:
    return ("Source Quench");
  case 5:
    return ("Redirect");
  case 6:
    return ("Alternate Host Address)");
  case 8:
    return ("Echo");
  case 9:
    return ("Router Advertisement");
  case 10:
    return ("Router Selection");
  case 11:
    return ("Time Exceeded");
  case 12:
    return ("Parameter Problem");
  case 13:
    return ("Timestamp");
  case 14:
    return ("Timestamp Reply");
  case 15:
    return ("Information Request");
  case 16:
    return ("Information Reply");
  case 17:
    return ("Address Mask Request");
  case 18:
    return ("Address Mask Reply");
  case 30:
    return ("Traceroute");
  case 31:
    return ("Datagram Conversion Error");
  case 32:
    return ("Mobile Host Redirect");
  case 33:
    return ("IPv6 Where-Are-You");
  case 34:
    return ("IPv6 I-Am-Here");
  case 35:
    return ("Mobile Registration Request");
  case 36:
    return ("Mobile Registration Reply");
  case 37:
    return ("Domain Name Request");
  case 38:
    return ("Domain Name Reply");
  case 39:
    return ("SKIP");
  case 40:
    return ("Photuris");
  }
  return ("UNKNOWN");
}


x86 assembly (clang, -O0):
<icmp_type>:
push   %rbp
mov    %rsp,%rbp
mov    %dil,%al
mov    %al,-0x9(%rbp)
movzbl -0x9(%rbp),%eax
mov    %rax,-0x18(%rbp)
sub    $0x28,%rax
ja     12e0 <icmp_type+0x1e0>
mov    -0x18(%rbp),%rax
lea    0xed9(%rip),%rcx
movslq (%rcx,%rax,4),%rax
add    %rcx,%rax
jmp    *%rax
lea    0xf6d(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    12eb <icmp_type+0x1eb>
lea    0xf68(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    12eb <icmp_type+0x1eb>
lea    0xf70(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    12eb <icmp_type+0x1eb>
lea    0x106a(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    12eb <icmp_type+0x1eb>
lea    0xf5e(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    12eb <icmp_type+0x1eb>
lea    0xf66(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    12eb <icmp_type+0x1eb>
lea    0xf5b(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    12eb <icmp_type+0x1eb>
lea    0xf60(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    12eb <icmp_type+0x1eb>
lea    0xf61(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    12eb <icmp_type+0x1eb>
lea    0xf5f(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    12eb <icmp_type+0x1eb>
lea    0xf61(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    12eb <icmp_type+0x1eb>
lea    0xf5b(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    12eb <icmp_type+0x1eb>
lea    0xf5b(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    12eb <icmp_type+0x1eb>
lea    0xf5f(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    12eb <icmp_type+0x1eb>
lea    0xf61(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    12eb <icmp_type+0x1eb>
lea    0xf66(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    12eb <icmp_type+0x1eb>
lea    0xf69(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    12eb <icmp_type+0x1eb>
lea    0xf64(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    12eb <icmp_type+0x1eb>
lea    0xf6e(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    12eb <icmp_type+0x1eb>
lea    0xf73(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    12eb <icmp_type+0x1eb>
lea    0xf76(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    12eb <icmp_type+0x1eb>
lea    0xf75(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    12eb <icmp_type+0x1eb>
lea    0xf81(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    12eb <icmp_type+0x1eb>
lea    0xf8b(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    12eb <icmp_type+0x1eb>
lea    0xf8f(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    12eb <icmp_type+0x1eb>
lea    0xf91(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    12eb <icmp_type+0x1eb>
lea    0xf86(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    12eb <icmp_type+0x1eb>
lea    0xf7f(%rip),%rax
mov    %rax,-0x8(%rbp)
mov    -0x8(%rbp),%rax
pop    %rbp
ret

x86 assembly (clang, -O2):
<icmp_type>:
cmp    $0x28,%dil
ja     1119 <icmp_type+0x19>
movsbq %dil,%rax
lea    0x10bb(%rip),%rcx
movslq (%rcx,%rax,4),%rax
add    %rcx,%rax
ret
lea    0x10a2(%rip),%rax
ret

LLVM IR (-O0):
@.str = [11 x i8] c"Echo Reply\00"
@.str.1 = [24 x i8] c"Destination Unreachable\00"
@.str.2 = [14 x i8] c"Source Quench\00"
@.str.3 = [9 x i8] c"Redirect\00"
@.str.4 = [24 x i8] c"Alternate Host Address)\00"
@.str.5 = [5 x i8] c"Echo\00"
@.str.6 = [21 x i8] c"Router Advertisement\00"
@.str.7 = [17 x i8] c"Router Selection\00"
@.str.8 = [14 x i8] c"Time Exceeded\00"
@.str.9 = [18 x i8] c"Parameter Problem\00"
@.str.10 = [10 x i8] c"Timestamp\00"
@.str.11 = [16 x i8] c"Timestamp Reply\00"
@.str.12 = [20 x i8] c"Information Request\00"
@.str.13 = [18 x i8] c"Information Reply\00"
@.str.14 = [21 x i8] c"Address Mask Request\00"
@.str.15 = [19 x i8] c"Address Mask Reply\00"
@.str.16 = [11 x i8] c"Traceroute\00"
@.str.17 = [26 x i8] c"Datagram Conversion Error\00"
@.str.18 = [21 x i8] c"Mobile Host Redirect\00"
@.str.19 = [19 x i8] c"IPv6 Where-Are-You\00"
@.str.20 = [15 x i8] c"IPv6 I-Am-Here\00"
@.str.21 = [28 x i8] c"Mobile Registration Request\00"
@.str.22 = [26 x i8] c"Mobile Registration Reply\00"
@.str.23 = [20 x i8] c"Domain Name Request\00"
@.str.24 = [18 x i8] c"Domain Name Reply\00"
@.str.25 = [5 x i8] c"SKIP\00"
@.str.26 = [9 x i8] c"Photuris\00"
@.str.27 = [8 x i8] c"UNKNOWN\00"
define i8* @icmp_type(i8 zeroext %0) {
%2 = alloca i8*
%3 = alloca i8
store i8 %0, i8* %3
%4 = load i8, i8* %3
%5 = zext i8 %4 to i32
switch i32 %5, label %33 [
i32 0, label %6
i32 3, label %7
i32 4, label %8
i32 5, label %9
i32 6, label %10
i32 8, label %11
i32 9, label %12
i32 10, label %13
i32 11, label %14
i32 12, label %15
i32 13, label %16
i32 14, label %17
i32 15, label %18
i32 16, label %19
i32 17, label %20
i32 18, label %21
i32 30, label %22
i32 31, label %23
i32 32, label %24
i32 33, label %25
i32 34, label %26
i32 35, label %27
i32 36, label %28
i32 37, label %29
i32 38, label %30
i32 39, label %31
i32 40, label %32
]
6: ; preds = %1
store i8* getelementptr inbounds ([11 x i8], [11 x i8]* @.str, i64 0, i64 0), i8** %2
br label %34
7: ; preds = %1
store i8* getelementptr inbounds ([24 x i8], [24 x i8]* @.str.1, i64 0, i64 0), i8** %2
br label %34
8: ; preds = %1
store i8* getelementptr inbounds ([14 x i8], [14 x i8]* @.str.2, i64 0, i64 0), i8** %2
br label %34
9: ; preds = %1
store i8* getelementptr inbounds ([9 x i8], [9 x i8]* @.str.3, i64 0, i64 0), i8** %2
br label %34
10: ; preds = %1
store i8* getelementptr inbounds ([24 x i8], [24 x i8]* @.str.4, i64 0, i64 0), i8** %2
br label %34
11: ; preds = %1
store i8* getelementptr inbounds ([5 x i8], [5 x i8]* @.str.5, i64 0, i64 0), i8** %2
br label %34
12: ; preds = %1
store i8* getelementptr inbounds ([21 x i8], [21 x i8]* @.str.6, i64 0, i64 0), i8** %2
br label %34
13: ; preds = %1
store i8* getelementptr inbounds ([17 x i8], [17 x i8]* @.str.7, i64 0, i64 0), i8** %2
br label %34
14: ; preds = %1
store i8* getelementptr inbounds ([14 x i8], [14 x i8]* @.str.8, i64 0, i64 0), i8** %2
br label %34
15: ; preds = %1
store i8* getelementptr inbounds ([18 x i8], [18 x i8]* @.str.9, i64 0, i64 0), i8** %2
br label %34
16: ; preds = %1
store i8* getelementptr inbounds ([10 x i8], [10 x i8]* @.str.10, i64 0, i64 0), i8** %2
br label %34
17: ; preds = %1
store i8* getelementptr inbounds ([16 x i8], [16 x i8]* @.str.11, i64 0, i64 0), i8** %2
br label %34
18: ; preds = %1
store i8* getelementptr inbounds ([20 x i8], [20 x i8]* @.str.12, i64 0, i64 0), i8** %2
br label %34
19: ; preds = %1
store i8* getelementptr inbounds ([18 x i8], [18 x i8]* @.str.13, i64 0, i64 0), i8** %2
br label %34
20: ; preds = %1
store i8* getelementptr inbounds ([21 x i8], [21 x i8]* @.str.14, i64 0, i64 0), i8** %2
br label %34
21: ; preds = %1
store i8* getelementptr inbounds ([19 x i8], [19 x i8]* @.str.15, i64 0, i64 0), i8** %2
br label %34
22: ; preds = %1
store i8* getelementptr inbounds ([11 x i8], [11 x i8]* @.str.16, i64 0, i64 0), i8** %2
br label %34
23: ; preds = %1
store i8* getelementptr inbounds ([26 x i8], [26 x i8]* @.str.17, i64 0, i64 0), i8** %2
br label %34
24: ; preds = %1
store i8* getelementptr inbounds ([21 x i8], [21 x i8]* @.str.18, i64 0, i64 0), i8** %2
br label %34
25: ; preds = %1
store i8* getelementptr inbounds ([19 x i8], [19 x i8]* @.str.19, i64 0, i64 0), i8** %2
br label %34
26: ; preds = %1
store i8* getelementptr inbounds ([15 x i8], [15 x i8]* @.str.20, i64 0, i64 0), i8** %2
br label %34
27: ; preds = %1
store i8* getelementptr inbounds ([28 x i8], [28 x i8]* @.str.21, i64 0, i64 0), i8** %2
br label %34
28: ; preds = %1
store i8* getelementptr inbounds ([26 x i8], [26 x i8]* @.str.22, i64 0, i64 0), i8** %2
br label %34
29: ; preds = %1
store i8* getelementptr inbounds ([20 x i8], [20 x i8]* @.str.23, i64 0, i64 0), i8** %2
br label %34
30: ; preds = %1
store i8* getelementptr inbounds ([18 x i8], [18 x i8]* @.str.24, i64 0, i64 0), i8** %2
br label %34
31: ; preds = %1
store i8* getelementptr inbounds ([5 x i8], [5 x i8]* @.str.25, i64 0, i64 0), i8** %2
br label %34
32: ; preds = %1
store i8* getelementptr inbounds ([9 x i8], [9 x i8]* @.str.26, i64 0, i64 0), i8** %2
br label %34
33: ; preds = %1
store i8* getelementptr inbounds ([8 x i8], [8 x i8]* @.str.27, i64 0, i64 0), i8** %2
br label %34
34: ; preds = %33, %32, %31, %30, %29, %28, %27, %26, %25, %24, %23, %22, %21, %20, %19, %18, %17, %16, %15, %14, %13, %12, %11, %10, %9, %8, %7, %6
%35 = load i8*, i8** %2
ret i8* %35
}

LLVM IR (-O2):
@.str = [11 x i8] c"Echo Reply\00"
@.str.1 = [24 x i8] c"Destination Unreachable\00"
@.str.2 = [14 x i8] c"Source Quench\00"
@.str.3 = [9 x i8] c"Redirect\00"
@.str.4 = [24 x i8] c"Alternate Host Address)\00"
@.str.5 = [5 x i8] c"Echo\00"
@.str.6 = [21 x i8] c"Router Advertisement\00"
@.str.7 = [17 x i8] c"Router Selection\00"
@.str.8 = [14 x i8] c"Time Exceeded\00"
@.str.9 = [18 x i8] c"Parameter Problem\00"
@.str.10 = [10 x i8] c"Timestamp\00"
@.str.11 = [16 x i8] c"Timestamp Reply\00"
@.str.12 = [20 x i8] c"Information Request\00"
@.str.13 = [18 x i8] c"Information Reply\00"
@.str.14 = [21 x i8] c"Address Mask Request\00"
@.str.15 = [19 x i8] c"Address Mask Reply\00"
@.str.16 = [11 x i8] c"Traceroute\00"
@.str.17 = [26 x i8] c"Datagram Conversion Error\00"
@.str.18 = [21 x i8] c"Mobile Host Redirect\00"
@.str.19 = [19 x i8] c"IPv6 Where-Are-You\00"
@.str.20 = [15 x i8] c"IPv6 I-Am-Here\00"
@.str.21 = [28 x i8] c"Mobile Registration Request\00"
@.str.22 = [26 x i8] c"Mobile Registration Reply\00"
@.str.23 = [20 x i8] c"Domain Name Request\00"
@.str.24 = [18 x i8] c"Domain Name Reply\00"
@.str.25 = [5 x i8] c"SKIP\00"
@.str.26 = [9 x i8] c"Photuris\00"
@.str.27 = [8 x i8] c"UNKNOWN\00"
@reltable.icmp_type = [41 x i32] [i32 trunc (i64 sub (i64 ptrtoint ([11 x i8]* @.str to i64), i64 ptrtoint ([41 x i32]* @reltable.icmp_type to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([8 x i8]* @.str.27 to i64), i64 ptrtoint ([41 x i32]* @reltable.icmp_type to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([8 x i8]* @.str.27 to i64), i64 ptrtoint ([41 x i32]* @reltable.icmp_type to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([24 x i8]* @.str.1 to i64), i64 ptrtoint ([41 x i32]* @reltable.icmp_type to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([14 x i8]* @.str.2 to i64), i64 ptrtoint ([41 x i32]* @reltable.icmp_type to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([9 x i8]* @.str.3 to i64), i64 ptrtoint ([41 x i32]* @reltable.icmp_type to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([24 x i8]* @.str.4 to i64), i64 ptrtoint ([41 x i32]* @reltable.icmp_type to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([8 x i8]* @.str.27 to i64), i64 ptrtoint ([41 x i32]* @reltable.icmp_type to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([5 x i8]* @.str.5 to i64), i64 ptrtoint ([41 x i32]* @reltable.icmp_type to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([21 x i8]* @.str.6 to i64), i64 ptrtoint ([41 x i32]* @reltable.icmp_type to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([17 x i8]* @.str.7 to i64), i64 ptrtoint ([41 x i32]* @reltable.icmp_type to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([14 x i8]* @.str.8 to i64), i64 ptrtoint ([41 x i32]* @reltable.icmp_type to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([18 x i8]* @.str.9 to i64), i64 ptrtoint ([41 x i32]* @reltable.icmp_type to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([10 x i8]* @.str.10 to i64), i64 ptrtoint ([41 x i32]* @reltable.icmp_type to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([16 x i8]* @.str.11 to i64), i64 ptrtoint ([41 x i32]* @reltable.icmp_type to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([20 x i8]* @.str.12 to i64), i64 ptrtoint ([41 x i32]* @reltable.icmp_type to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([18 x i8]* @.str.13 to i64), i64 ptrtoint ([41 x i32]* @reltable.icmp_type to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([21 x i8]* @.str.14 to i64), i64 ptrtoint ([41 x i32]* @reltable.icmp_type to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([19 x i8]* @.str.15 to i64), i64 ptrtoint ([41 x i32]* @reltable.icmp_type to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([8 x i8]* @.str.27 to i64), i64 ptrtoint ([41 x i32]* @reltable.icmp_type to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([8 x i8]* @.str.27 to i64), i64 ptrtoint ([41 x i32]* @reltable.icmp_type to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([8 x i8]* @.str.27 to i64), i64 ptrtoint ([41 x i32]* @reltable.icmp_type to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([8 x i8]* @.str.27 to i64), i64 ptrtoint ([41 x i32]* @reltable.icmp_type to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([8 x i8]* @.str.27 to i64), i64 ptrtoint ([41 x i32]* @reltable.icmp_type to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([8 x i8]* @.str.27 to i64), i64 ptrtoint ([41 x i32]* @reltable.icmp_type to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([8 x i8]* @.str.27 to i64), i64 ptrtoint ([41 x i32]* @reltable.icmp_type to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([8 x i8]* @.str.27 to i64), i64 ptrtoint ([41 x i32]* @reltable.icmp_type to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([8 x i8]* @.str.27 to i64), i64 ptrtoint ([41 x i32]* @reltable.icmp_type to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([8 x i8]* @.str.27 to i64), i64 ptrtoint ([41 x i32]* @reltable.icmp_type to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([8 x i8]* @.str.27 to i64), i64 ptrtoint ([41 x i32]* @reltable.icmp_type to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([11 x i8]* @.str.16 to i64), i64 ptrtoint ([41 x i32]* @reltable.icmp_type to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([26 x i8]* @.str.17 to i64), i64 ptrtoint ([41 x i32]* @reltable.icmp_type to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([21 x i8]* @.str.18 to i64), i64 ptrtoint ([41 x i32]* @reltable.icmp_type to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([19 x i8]* @.str.19 to i64), i64 ptrtoint ([41 x i32]* @reltable.icmp_type to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([15 x i8]* @.str.20 to i64), i64 ptrtoint ([41 x i32]* @reltable.icmp_type to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([28 x i8]* @.str.21 to i64), i64 ptrtoint ([41 x i32]* @reltable.icmp_type to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([26 x i8]* @.str.22 to i64), i64 ptrtoint ([41 x i32]* @reltable.icmp_type to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([20 x i8]* @.str.23 to i64), i64 ptrtoint ([41 x i32]* @reltable.icmp_type to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([18 x i8]* @.str.24 to i64), i64 ptrtoint ([41 x i32]* @reltable.icmp_type to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([5 x i8]* @.str.25 to i64), i64 ptrtoint ([41 x i32]* @reltable.icmp_type to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([9 x i8]* @.str.26 to i64), i64 ptrtoint ([41 x i32]* @reltable.icmp_type to i64)) to i32)]
define i8* @icmp_type(i8 zeroext %0) {
%2 = icmp ult i8 %0, 41
br i1 %2, label %3, label %7
3: ; preds = %1
%4 = sext i8 %0 to i64
%5 = shl i64 %4, 2
%6 = call i8* @llvm.load.relative.i64(i8* bitcast ([41 x i32]* @reltable.icmp_type 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.27, i64 0, i64 0), %1 ]
ret i8* %8
}