char *get_level_prefix(level) {
  char *level_prefix;
  switch (level) {
  case 0:
    level_prefix = "[INFO]";
    break;
  case 3:
    level_prefix = "[DEBUG]";
    break;
  case 2:
    level_prefix = "[WARN]";
    break;
  case 1:
    level_prefix = "[ERROR]";
    break;
  default:
    level_prefix = "";
    break;
  }
  return level_prefix;
}


x86 assembly (clang, -O0):
<get_level_prefix>:
push   %rbp
mov    %rsp,%rbp
mov    %edi,-0x4(%rbp)
mov    -0x4(%rbp),%eax
mov    %rax,-0x18(%rbp)
sub    $0x3,%rax
ja     116c <get_level_prefix+0x6c>
mov    -0x18(%rbp),%rax
lea    0xedd(%rip),%rcx
movslq (%rcx,%rax,4),%rax
add    %rcx,%rax
jmp    *%rax
lea    0xedd(%rip),%rax
mov    %rax,-0x10(%rbp)
jmp    1177 <get_level_prefix+0x77>
lea    0xed4(%rip),%rax
mov    %rax,-0x10(%rbp)
jmp    1177 <get_level_prefix+0x77>
lea    0xecc(%rip),%rax
mov    %rax,-0x10(%rbp)
jmp    1177 <get_level_prefix+0x77>
lea    0xec3(%rip),%rax
mov    %rax,-0x10(%rbp)
jmp    1177 <get_level_prefix+0x77>
lea    0xeab(%rip),%rax
mov    %rax,-0x10(%rbp)
mov    -0x10(%rbp),%rax
pop    %rbp
ret

x86 assembly (clang, -O2):
<get_level_prefix>:
cmp    $0x3,%edi
ja     1117 <get_level_prefix+0x17>
movslq %edi,%rax
lea    0xf11(%rip),%rcx
movslq (%rcx,%rax,4),%rax
add    %rcx,%rax
ret
lea    0xef0(%rip),%rax
ret

LLVM IR (-O0):
@.str = [7 x i8] c"[INFO]\00"
@.str.1 = [8 x i8] c"[DEBUG]\00"
@.str.2 = [7 x i8] c"[WARN]\00"
@.str.3 = [8 x i8] c"[ERROR]\00"
@.str.4 = [1 x i8] zeroinitializer
define i8* @get_level_prefix(i32 %0) {
%2 = alloca i32
%3 = alloca i8*
store i32 %0, i32* %2
%4 = load i32, i32* %2
switch i32 %4, label %9 [
i32 0, label %5
i32 3, label %6
i32 2, label %7
i32 1, label %8
]
5: ; preds = %1
store i8* getelementptr inbounds ([7 x i8], [7 x i8]* @.str, i64 0, i64 0), i8** %3
br label %10
6: ; preds = %1
store i8* getelementptr inbounds ([8 x i8], [8 x i8]* @.str.1, i64 0, i64 0), i8** %3
br label %10
7: ; preds = %1
store i8* getelementptr inbounds ([7 x i8], [7 x i8]* @.str.2, i64 0, i64 0), i8** %3
br label %10
8: ; preds = %1
store i8* getelementptr inbounds ([8 x i8], [8 x i8]* @.str.3, i64 0, i64 0), i8** %3
br label %10
9: ; preds = %1
store i8* getelementptr inbounds ([1 x i8], [1 x i8]* @.str.4, i64 0, i64 0), i8** %3
br label %10
10: ; preds = %9, %8, %7, %6, %5
%11 = load i8*, i8** %3
ret i8* %11
}

LLVM IR (-O2):
@.str = [7 x i8] c"[INFO]\00"
@.str.1 = [8 x i8] c"[DEBUG]\00"
@.str.2 = [7 x i8] c"[WARN]\00"
@.str.3 = [8 x i8] c"[ERROR]\00"
@.str.4 = [1 x i8] zeroinitializer
@reltable.get_level_prefix = [4 x i32] [i32 trunc (i64 sub (i64 ptrtoint ([7 x i8]* @.str to i64), i64 ptrtoint ([4 x i32]* @reltable.get_level_prefix to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([8 x i8]* @.str.3 to i64), i64 ptrtoint ([4 x i32]* @reltable.get_level_prefix to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([7 x i8]* @.str.2 to i64), i64 ptrtoint ([4 x i32]* @reltable.get_level_prefix to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([8 x i8]* @.str.1 to i64), i64 ptrtoint ([4 x i32]* @reltable.get_level_prefix to i64)) to i32)]
define i8* @get_level_prefix(i32 %0) {
%2 = icmp ult i32 %0, 4
br i1 %2, label %3, label %7
3: ; preds = %1
%4 = sext i32 %0 to i64
%5 = shl i64 %4, 2
%6 = call i8* @llvm.load.relative.i64(i8* bitcast ([4 x i32]* @reltable.get_level_prefix to i8*), i64 %5)
br label %7
7: ; preds = %1, %3
%8 = phi i8* [ %6, %3 ], [ getelementptr inbounds ([1 x i8], [1 x i8]* @.str.4, i64 0, i64 0), %1 ]
ret i8* %8
}