const char *pn_code(int code) {
  switch (code) {
  case 0:
    return "<ok>";
  case (-1):
    return "PN_EOS";
  case (-2):
    return "PN_ERR";
  case (-3):
    return "PN_OVERFLOW";
  case (-4):
    return "PN_UNDERFLOW";
  case (-5):
    return "PN_STATE_ERR";
  case (-6):
    return "PN_ARG_ERR";
  case (-7):
    return "PN_TIMEOUT";
  case (-8):
    return "PN_INTR";
  default:
    return "<unknown>";
  }
}


x86 assembly (clang, -O0):
<pn_code>:
push   %rbp
mov    %rsp,%rbp
mov    %edi,-0xc(%rbp)
mov    -0xc(%rbp),%eax
add    $0x8,%eax
mov    %eax,%ecx
mov    %rcx,-0x18(%rbp)
sub    $0x8,%eax
ja     11c0 <pn_code+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 <pn_code+0xcb>
lea    0xee2(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    11cb <pn_code+0xcb>
lea    0xed9(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    11cb <pn_code+0xcb>
lea    0xed0(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    11cb <pn_code+0xcb>
lea    0xecc(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    11cb <pn_code+0xcb>
lea    0xec9(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    11cb <pn_code+0xcb>
lea    0xec6(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    11cb <pn_code+0xcb>
lea    0xec1(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    11cb <pn_code+0xcb>
lea    0xebc(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    11cb <pn_code+0xcb>
lea    0xeb4(%rip),%rax
mov    %rax,-0x8(%rbp)
mov    -0x8(%rbp),%rax
pop    %rbp
ret

x86 assembly (clang, -O2):
<pn_code>:
add    $0x8,%edi
cmp    $0x8,%edi
ja     111a <pn_code+0x1a>
movslq %edi,%rax
lea    0xf52(%rip),%rcx
movslq (%rcx,%rax,4),%rax
add    %rcx,%rax
ret
lea    0xf36(%rip),%rax
ret

LLVM IR (-O0):
@.str = [5 x i8] c"<ok>\00"
@.str.1 = [7 x i8] c"PN_EOS\00"
@.str.2 = [7 x i8] c"PN_ERR\00"
@.str.3 = [12 x i8] c"PN_OVERFLOW\00"
@.str.4 = [13 x i8] c"PN_UNDERFLOW\00"
@.str.5 = [13 x i8] c"PN_STATE_ERR\00"
@.str.6 = [11 x i8] c"PN_ARG_ERR\00"
@.str.7 = [11 x i8] c"PN_TIMEOUT\00"
@.str.8 = [8 x i8] c"PN_INTR\00"
@.str.9 = [10 x i8] c"<unknown>\00"
define i8* @pn_code(i32 %0) {
%2 = alloca i8*
%3 = alloca i32
store i32 %0, i32* %3
%4 = load i32, i32* %3
switch i32 %4, label %14 [
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
]
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 ([7 x i8], [7 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 ([12 x i8], [12 x i8]* @.str.3, i64 0, i64 0), i8** %2
br label %15
9: ; preds = %1
store i8* getelementptr inbounds ([13 x i8], [13 x i8]* @.str.4, i64 0, i64 0), i8** %2
br label %15
10: ; preds = %1
store i8* getelementptr inbounds ([13 x i8], [13 x i8]* @.str.5, i64 0, i64 0), i8** %2
br label %15
11: ; preds = %1
store i8* getelementptr inbounds ([11 x i8], [11 x i8]* @.str.6, i64 0, i64 0), i8** %2
br label %15
12: ; preds = %1
store i8* getelementptr inbounds ([11 x i8], [11 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 ([10 x i8], [10 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"<ok>\00"
@.str.1 = [7 x i8] c"PN_EOS\00"
@.str.2 = [7 x i8] c"PN_ERR\00"
@.str.3 = [12 x i8] c"PN_OVERFLOW\00"
@.str.4 = [13 x i8] c"PN_UNDERFLOW\00"
@.str.5 = [13 x i8] c"PN_STATE_ERR\00"
@.str.6 = [11 x i8] c"PN_ARG_ERR\00"
@.str.7 = [11 x i8] c"PN_TIMEOUT\00"
@.str.8 = [8 x i8] c"PN_INTR\00"
@.str.9 = [10 x i8] c"<unknown>\00"
@reltable.pn_code = [9 x i32] [i32 trunc (i64 sub (i64 ptrtoint ([8 x i8]* @.str.8 to i64), i64 ptrtoint ([9 x i32]* @reltable.pn_code to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([11 x i8]* @.str.7 to i64), i64 ptrtoint ([9 x i32]* @reltable.pn_code to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([11 x i8]* @.str.6 to i64), i64 ptrtoint ([9 x i32]* @reltable.pn_code to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([13 x i8]* @.str.5 to i64), i64 ptrtoint ([9 x i32]* @reltable.pn_code to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([13 x i8]* @.str.4 to i64), i64 ptrtoint ([9 x i32]* @reltable.pn_code to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([12 x i8]* @.str.3 to i64), i64 ptrtoint ([9 x i32]* @reltable.pn_code to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([7 x i8]* @.str.2 to i64), i64 ptrtoint ([9 x i32]* @reltable.pn_code to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([7 x i8]* @.str.1 to i64), i64 ptrtoint ([9 x i32]* @reltable.pn_code to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([5 x i8]* @.str to i64), i64 ptrtoint ([9 x i32]* @reltable.pn_code to i64)) to i32)]
define i8* @pn_code(i32 %0) {
%2 = add i32 %0, 8
%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.pn_code to i8*), i64 %6)
br label %8
8: ; preds = %1, %4
%9 = phi i8* [ %7, %4 ], [ getelementptr inbounds ([10 x i8], [10 x i8]* @.str.9, i64 0, i64 0), %1 ]
ret i8* %9
}