#define NULL ((void *)0)
typedef unsigned long size_t; // Customize by platform.
typedef long intptr_t;
typedef unsigned long uintptr_t;
typedef long scalar_t__; // Either arithmetic or pointer type.
/* By default, we understand bool (as a convenience). */
typedef int bool;
#define false 0
#define true 1

/* Forward declarations */

/* Type definitions */
typedef int uint32_t;

/* Variables and functions */
#define IPPROTO_ICMP 136
#define IPPROTO_IGMP 135
#define IPPROTO_IPIP 134
#define IPPROTO_IPV6 133
#define IPPROTO_RAW 132
#define IPPROTO_SCTP 131
#define IPPROTO_TCP 130
#define IPPROTO_UDP 129
#define IPPROTO_UDPLITE 128
const char *IPProto2Str(uint32_t proto) {
  switch (proto) {
  case IPPROTO_ICMP:
    return "ICMP";
  case IPPROTO_IGMP:
    return "IGMP";
  case IPPROTO_IPIP:
    return "IPIP";
  case IPPROTO_TCP:
    return "TCP";
  case IPPROTO_UDP:
    return "UDP";
  case IPPROTO_IPV6:
    return "IPv6";
  case IPPROTO_SCTP:
    return "SCTP";
  case IPPROTO_RAW:
    return "RAWIP";
  case IPPROTO_UDPLITE:
    return "UDPLITE";
  default:
    return "UNKNOWN";
  }
}


x86 assembly (clang, -O0):
<IPProto2Str>:
push   %rbp
mov    %rsp,%rbp
mov    %edi,-0xc(%rbp)
mov    -0xc(%rbp),%eax
add    $0xffffff80,%eax
mov    %eax,%ecx
mov    %rcx,-0x18(%rbp)
sub    $0x8,%eax
ja     11c0 <IPProto2Str+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 <IPProto2Str+0xcb>
lea    0xee2(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    11cb <IPProto2Str+0xcb>
lea    0xed7(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    11cb <IPProto2Str+0xcb>
lea    0xecc(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    11cb <IPProto2Str+0xcb>
lea    0xec0(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    11cb <IPProto2Str+0xcb>
lea    0xeb4(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    11cb <IPProto2Str+0xcb>
lea    0xea9(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    11cb <IPProto2Str+0xcb>
lea    0xe9e(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    11cb <IPProto2Str+0xcb>
lea    0xe94(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    11cb <IPProto2Str+0xcb>
lea    0xe8c(%rip),%rax
mov    %rax,-0x8(%rbp)
mov    -0x8(%rbp),%rax
pop    %rbp
ret

x86 assembly (clang, -O2):
<IPProto2Str>:
add    $0xffffff80,%edi
cmp    $0x8,%edi
ja     111a <IPProto2Str+0x1a>
movslq %edi,%rax
lea    0xf26(%rip),%rcx
movslq (%rcx,%rax,4),%rax
add    %rcx,%rax
ret
lea    0xf0e(%rip),%rax
ret

LLVM IR (-O0):
@.str = [5 x i8] c"ICMP\00"
@.str.1 = [5 x i8] c"IGMP\00"
@.str.2 = [5 x i8] c"IPIP\00"
@.str.3 = [4 x i8] c"TCP\00"
@.str.4 = [4 x i8] c"UDP\00"
@.str.5 = [5 x i8] c"IPv6\00"
@.str.6 = [5 x i8] c"SCTP\00"
@.str.7 = [6 x i8] c"RAWIP\00"
@.str.8 = [8 x i8] c"UDPLITE\00"
@.str.9 = [8 x i8] c"UNKNOWN\00"
define i8* @IPProto2Str(i32 %0) {
%2 = alloca i8*
%3 = alloca i32
store i32 %0, i32* %3
%4 = load i32, i32* %3
switch i32 %4, label %14 [
i32 136, label %5
i32 135, label %6
i32 134, label %7
i32 130, label %8
i32 129, label %9
i32 133, label %10
i32 131, label %11
i32 132, label %12
i32 128, 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 ([5 x i8], [5 x i8]* @.str.1, i64 0, i64 0), i8** %2
br label %15
7: ; preds = %1
store i8* getelementptr inbounds ([5 x i8], [5 x i8]* @.str.2, i64 0, i64 0), i8** %2
br label %15
8: ; preds = %1
store i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str.3, i64 0, i64 0), i8** %2
br label %15
9: ; preds = %1
store i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str.4, i64 0, i64 0), i8** %2
br label %15
10: ; preds = %1
store i8* getelementptr inbounds ([5 x i8], [5 x i8]* @.str.5, i64 0, i64 0), i8** %2
br label %15
11: ; preds = %1
store i8* getelementptr inbounds ([5 x i8], [5 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 ([8 x i8], [8 x i8]* @.str.8, i64 0, i64 0), i8** %2
br label %15
14: ; preds = %1
store i8* getelementptr inbounds ([8 x i8], [8 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"ICMP\00"
@.str.1 = [5 x i8] c"IGMP\00"
@.str.2 = [5 x i8] c"IPIP\00"
@.str.3 = [4 x i8] c"TCP\00"
@.str.4 = [4 x i8] c"UDP\00"
@.str.5 = [5 x i8] c"IPv6\00"
@.str.6 = [5 x i8] c"SCTP\00"
@.str.7 = [6 x i8] c"RAWIP\00"
@.str.8 = [8 x i8] c"UDPLITE\00"
@.str.9 = [8 x i8] c"UNKNOWN\00"
@reltable.IPProto2Str = [9 x i32] [i32 trunc (i64 sub (i64 ptrtoint ([8 x i8]* @.str.8 to i64), i64 ptrtoint ([9 x i32]* @reltable.IPProto2Str to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([4 x i8]* @.str.4 to i64), i64 ptrtoint ([9 x i32]* @reltable.IPProto2Str to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([4 x i8]* @.str.3 to i64), i64 ptrtoint ([9 x i32]* @reltable.IPProto2Str to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([5 x i8]* @.str.6 to i64), i64 ptrtoint ([9 x i32]* @reltable.IPProto2Str to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([6 x i8]* @.str.7 to i64), i64 ptrtoint ([9 x i32]* @reltable.IPProto2Str to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([5 x i8]* @.str.5 to i64), i64 ptrtoint ([9 x i32]* @reltable.IPProto2Str to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([5 x i8]* @.str.2 to i64), i64 ptrtoint ([9 x i32]* @reltable.IPProto2Str to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([5 x i8]* @.str.1 to i64), i64 ptrtoint ([9 x i32]* @reltable.IPProto2Str to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([5 x i8]* @.str to i64), i64 ptrtoint ([9 x i32]* @reltable.IPProto2Str to i64)) to i32)]
define i8* @IPProto2Str(i32 %0) {
%2 = add i32 %0, -128
%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.IPProto2Str to i8*), i64 %6)
br label %8
8: ; preds = %1, %4
%9 = phi i8* [ %7, %4 ], [ getelementptr inbounds ([8 x i8], [8 x i8]* @.str.9, i64 0, i64 0), %1 ]
ret i8* %9
}