char *get_levelstr(int level) {
  switch (level) {
  case 1:
    return "ERROR";
  case 6:
    return "INFO ";
  case 7:
    return "DEBUG";
  default:
    return "?????";
  }
}


x86 assembly (clang, -O0):
<get_levelstr>:
push   %rbp
mov    %rsp,%rbp
mov    %edi,-0xc(%rbp)
mov    -0xc(%rbp),%eax
mov    %eax,-0x10(%rbp)
sub    $0x1,%eax
je     113d <get_levelstr+0x3d>
jmp    111b <get_levelstr+0x1b>
mov    -0x10(%rbp),%eax
sub    $0x6,%eax
je     114d <get_levelstr+0x4d>
jmp    112c <get_levelstr+0x2c>
mov    -0x10(%rbp),%eax
sub    $0x7,%eax
je     115d <get_levelstr+0x5d>
jmp    116d <get_levelstr+0x6d>
lea    0xebc(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    1178 <get_levelstr+0x78>
lea    0xeb2(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    1178 <get_levelstr+0x78>
lea    0xea8(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    1178 <get_levelstr+0x78>
lea    0xe9e(%rip),%rax
mov    %rax,-0x8(%rbp)
mov    -0x8(%rbp),%rax
pop    %rbp
ret

x86 assembly (clang, -O2):
<get_levelstr>:
add    $0xffffffff,%edi
cmp    $0x6,%edi
ja     111a <get_levelstr+0x1a>
movslq %edi,%rax
lea    0xf06(%rip),%rcx
movslq (%rcx,%rax,4),%rax
add    %rcx,%rax
ret
lea    0xef1(%rip),%rax
ret

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

LLVM IR (-O2):
@.str = [6 x i8] c"ERROR\00"
@.str.1 = [6 x i8] c"INFO \00"
@.str.2 = [6 x i8] c"DEBUG\00"
@.str.3 = [6 x i8] c"?????\00"
@reltable.get_levelstr = [7 x i32] [i32 trunc (i64 sub (i64 ptrtoint ([6 x i8]* @.str to i64), i64 ptrtoint ([7 x i32]* @reltable.get_levelstr to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([6 x i8]* @.str.3 to i64), i64 ptrtoint ([7 x i32]* @reltable.get_levelstr to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([6 x i8]* @.str.3 to i64), i64 ptrtoint ([7 x i32]* @reltable.get_levelstr to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([6 x i8]* @.str.3 to i64), i64 ptrtoint ([7 x i32]* @reltable.get_levelstr to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([6 x i8]* @.str.3 to i64), i64 ptrtoint ([7 x i32]* @reltable.get_levelstr to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([6 x i8]* @.str.1 to i64), i64 ptrtoint ([7 x i32]* @reltable.get_levelstr to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([6 x i8]* @.str.2 to i64), i64 ptrtoint ([7 x i32]* @reltable.get_levelstr to i64)) to i32)]
define i8* @get_levelstr(i32 %0) {
%2 = add i32 %0, -1
%3 = icmp ult i32 %2, 7
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 ([7 x i32]* @reltable.get_levelstr to i8*), i64 %6)
br label %8
8: ; preds = %1, %4
%9 = phi i8* [ %7, %4 ], [ getelementptr inbounds ([6 x i8], [6 x i8]* @.str.3, i64 0, i64 0), %1 ]
ret i8* %9
}