char *pri_event2str(int id) {
  switch (id) {
  case 1:
    return "D-Channel Up";
  case 2:
    return "D-channel Down";
  case 3:
    return "Restart channel";
  case 5:
    return "Ring";
  case 6:
    return "Hangup";
  case 7:
    return "Ringing";
  case 8:
    return "Answer";
  case 9:
    return "Hangup ACK";
  case 10:
    return "Restart ACK";
  case 11:
    return "FacName";
  case 12:
    return "Info Received";
  case 13:
    return "Proceeding";
  case 14:
    return "Setup ACK";
  case 15:
    return "Hangup Req";
  case 16:
    return "Notify";
  case 17:
    return "Progress";
  case 4:
    return "Configuration Error";
  default:
    return "Unknown Event";
  }
}


x86 assembly (clang, -O0):
<pri_event2str>:
push   %rbp
mov    %rsp,%rbp
mov    %edi,-0xc(%rbp)
mov    -0xc(%rbp),%eax
add    $0xffffffff,%eax
mov    %eax,%ecx
mov    %rcx,-0x18(%rbp)
sub    $0x10,%eax
ja     1240 <pri_event2str+0x140>
mov    -0x18(%rbp),%rax
lea    0xed9(%rip),%rcx
movslq (%rcx,%rax,4),%rax
add    %rcx,%rax
jmp    *%rax
lea    0xf0d(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    124b <pri_event2str+0x14b>
lea    0xf0a(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    124b <pri_event2str+0x14b>
lea    0xf09(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    124b <pri_event2str+0x14b>
lea    0xf09(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    124b <pri_event2str+0x14b>
lea    0xefe(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    124b <pri_event2str+0x14b>
lea    0xef5(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    124b <pri_event2str+0x14b>
lea    0xeed(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    124b <pri_event2str+0x14b>
lea    0xee4(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    124b <pri_event2str+0x14b>
lea    0xedf(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    124b <pri_event2str+0x14b>
lea    0xedb(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    124b <pri_event2str+0x14b>
lea    0xed3(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    124b <pri_event2str+0x14b>
lea    0xed1(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    124b <pri_event2str+0x14b>
lea    0xecc(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    124b <pri_event2str+0x14b>
lea    0xec6(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    124b <pri_event2str+0x14b>
lea    0xec1(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    124b <pri_event2str+0x14b>
lea    0xeb8(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    124b <pri_event2str+0x14b>
lea    0xeb1(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    124b <pri_event2str+0x14b>
lea    0xeb5(%rip),%rax
mov    %rax,-0x8(%rbp)
mov    -0x8(%rbp),%rax
pop    %rbp
ret

x86 assembly (clang, -O2):
<pri_event2str>:
add    $0xffffffff,%edi
cmp    $0x10,%edi
ja     111a <pri_event2str+0x1a>
movslq %edi,%rax
lea    0xfb6(%rip),%rcx
movslq (%rcx,%rax,4),%rax
add    %rcx,%rax
ret
lea    0xf97(%rip),%rax
ret

LLVM IR (-O0):
@.str = [13 x i8] c"D-Channel Up\00"
@.str.1 = [15 x i8] c"D-channel Down\00"
@.str.2 = [16 x i8] c"Restart channel\00"
@.str.3 = [5 x i8] c"Ring\00"
@.str.4 = [7 x i8] c"Hangup\00"
@.str.5 = [8 x i8] c"Ringing\00"
@.str.6 = [7 x i8] c"Answer\00"
@.str.7 = [11 x i8] c"Hangup ACK\00"
@.str.8 = [12 x i8] c"Restart ACK\00"
@.str.9 = [8 x i8] c"FacName\00"
@.str.10 = [14 x i8] c"Info Received\00"
@.str.11 = [11 x i8] c"Proceeding\00"
@.str.12 = [10 x i8] c"Setup ACK\00"
@.str.13 = [11 x i8] c"Hangup Req\00"
@.str.14 = [7 x i8] c"Notify\00"
@.str.15 = [9 x i8] c"Progress\00"
@.str.16 = [20 x i8] c"Configuration Error\00"
@.str.17 = [14 x i8] c"Unknown Event\00"
define i8* @pri_event2str(i32 %0) {
%2 = alloca i8*
%3 = alloca i32
store i32 %0, i32* %3
%4 = load i32, i32* %3
switch i32 %4, label %22 [
i32 1, label %5
i32 2, label %6
i32 3, label %7
i32 5, label %8
i32 6, label %9
i32 7, 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 4, label %21
]
5: ; preds = %1
store i8* getelementptr inbounds ([13 x i8], [13 x i8]* @.str, i64 0, i64 0), i8** %2
br label %23
6: ; preds = %1
store i8* getelementptr inbounds ([15 x i8], [15 x i8]* @.str.1, i64 0, i64 0), i8** %2
br label %23
7: ; preds = %1
store i8* getelementptr inbounds ([16 x i8], [16 x i8]* @.str.2, i64 0, i64 0), i8** %2
br label %23
8: ; preds = %1
store i8* getelementptr inbounds ([5 x i8], [5 x i8]* @.str.3, i64 0, i64 0), i8** %2
br label %23
9: ; preds = %1
store i8* getelementptr inbounds ([7 x i8], [7 x i8]* @.str.4, i64 0, i64 0), i8** %2
br label %23
10: ; preds = %1
store i8* getelementptr inbounds ([8 x i8], [8 x i8]* @.str.5, i64 0, i64 0), i8** %2
br label %23
11: ; preds = %1
store i8* getelementptr inbounds ([7 x i8], [7 x i8]* @.str.6, i64 0, i64 0), i8** %2
br label %23
12: ; preds = %1
store i8* getelementptr inbounds ([11 x i8], [11 x i8]* @.str.7, i64 0, i64 0), i8** %2
br label %23
13: ; preds = %1
store i8* getelementptr inbounds ([12 x i8], [12 x i8]* @.str.8, i64 0, i64 0), i8** %2
br label %23
14: ; preds = %1
store i8* getelementptr inbounds ([8 x i8], [8 x i8]* @.str.9, i64 0, i64 0), i8** %2
br label %23
15: ; preds = %1
store i8* getelementptr inbounds ([14 x i8], [14 x i8]* @.str.10, i64 0, i64 0), i8** %2
br label %23
16: ; preds = %1
store i8* getelementptr inbounds ([11 x i8], [11 x i8]* @.str.11, i64 0, i64 0), i8** %2
br label %23
17: ; preds = %1
store i8* getelementptr inbounds ([10 x i8], [10 x i8]* @.str.12, i64 0, i64 0), i8** %2
br label %23
18: ; preds = %1
store i8* getelementptr inbounds ([11 x i8], [11 x i8]* @.str.13, i64 0, i64 0), i8** %2
br label %23
19: ; preds = %1
store i8* getelementptr inbounds ([7 x i8], [7 x i8]* @.str.14, i64 0, i64 0), i8** %2
br label %23
20: ; preds = %1
store i8* getelementptr inbounds ([9 x i8], [9 x i8]* @.str.15, i64 0, i64 0), i8** %2
br label %23
21: ; preds = %1
store i8* getelementptr inbounds ([20 x i8], [20 x i8]* @.str.16, i64 0, i64 0), i8** %2
br label %23
22: ; preds = %1
store i8* getelementptr inbounds ([14 x i8], [14 x i8]* @.str.17, i64 0, i64 0), i8** %2
br label %23
23: ; preds = %22, %21, %20, %19, %18, %17, %16, %15, %14, %13, %12, %11, %10, %9, %8, %7, %6, %5
%24 = load i8*, i8** %2
ret i8* %24
}

LLVM IR (-O2):
@.str = [13 x i8] c"D-Channel Up\00"
@.str.1 = [15 x i8] c"D-channel Down\00"
@.str.2 = [16 x i8] c"Restart channel\00"
@.str.3 = [5 x i8] c"Ring\00"
@.str.4 = [7 x i8] c"Hangup\00"
@.str.5 = [8 x i8] c"Ringing\00"
@.str.6 = [7 x i8] c"Answer\00"
@.str.7 = [11 x i8] c"Hangup ACK\00"
@.str.8 = [12 x i8] c"Restart ACK\00"
@.str.9 = [8 x i8] c"FacName\00"
@.str.10 = [14 x i8] c"Info Received\00"
@.str.11 = [11 x i8] c"Proceeding\00"
@.str.12 = [10 x i8] c"Setup ACK\00"
@.str.13 = [11 x i8] c"Hangup Req\00"
@.str.14 = [7 x i8] c"Notify\00"
@.str.15 = [9 x i8] c"Progress\00"
@.str.16 = [20 x i8] c"Configuration Error\00"
@.str.17 = [14 x i8] c"Unknown Event\00"
@reltable.pri_event2str = [17 x i32] [i32 trunc (i64 sub (i64 ptrtoint ([13 x i8]* @.str to i64), i64 ptrtoint ([17 x i32]* @reltable.pri_event2str to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([15 x i8]* @.str.1 to i64), i64 ptrtoint ([17 x i32]* @reltable.pri_event2str to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([16 x i8]* @.str.2 to i64), i64 ptrtoint ([17 x i32]* @reltable.pri_event2str to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([20 x i8]* @.str.16 to i64), i64 ptrtoint ([17 x i32]* @reltable.pri_event2str to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([5 x i8]* @.str.3 to i64), i64 ptrtoint ([17 x i32]* @reltable.pri_event2str to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([7 x i8]* @.str.4 to i64), i64 ptrtoint ([17 x i32]* @reltable.pri_event2str to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([8 x i8]* @.str.5 to i64), i64 ptrtoint ([17 x i32]* @reltable.pri_event2str to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([7 x i8]* @.str.6 to i64), i64 ptrtoint ([17 x i32]* @reltable.pri_event2str to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([11 x i8]* @.str.7 to i64), i64 ptrtoint ([17 x i32]* @reltable.pri_event2str to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([12 x i8]* @.str.8 to i64), i64 ptrtoint ([17 x i32]* @reltable.pri_event2str to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([8 x i8]* @.str.9 to i64), i64 ptrtoint ([17 x i32]* @reltable.pri_event2str to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([14 x i8]* @.str.10 to i64), i64 ptrtoint ([17 x i32]* @reltable.pri_event2str to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([11 x i8]* @.str.11 to i64), i64 ptrtoint ([17 x i32]* @reltable.pri_event2str to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([10 x i8]* @.str.12 to i64), i64 ptrtoint ([17 x i32]* @reltable.pri_event2str to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([11 x i8]* @.str.13 to i64), i64 ptrtoint ([17 x i32]* @reltable.pri_event2str to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([7 x i8]* @.str.14 to i64), i64 ptrtoint ([17 x i32]* @reltable.pri_event2str to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([9 x i8]* @.str.15 to i64), i64 ptrtoint ([17 x i32]* @reltable.pri_event2str to i64)) to i32)]
define i8* @pri_event2str(i32 %0) {
%2 = add i32 %0, -1
%3 = icmp ult i32 %2, 17
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 ([17 x i32]* @reltable.pri_event2str to i8*), i64 %6)
br label %8
8: ; preds = %1, %4
%9 = phi i8* [ %7, %4 ], [ getelementptr inbounds ([14 x i8], [14 x i8]* @.str.17, i64 0, i64 0), %1 ]
ret i8* %9
}