char *login_err_txt(int err_code) {
  switch (err_code) {
  case 1:
    return "The provided username does not exist.";
  case 2:
    return "The provided password was incorrect.";
  case 0:
    return "The login was a success.";
  default:
    return "Uhhh..... yeah.";
  }
}


x86 assembly (clang, -O0):
<login_err_txt>:
push   %rbp
mov    %rsp,%rbp
mov    %edi,-0xc(%rbp)
mov    -0xc(%rbp),%eax
mov    %eax,-0x10(%rbp)
test   %eax,%eax
je     115c <login_err_txt+0x5c>
jmp    111a <login_err_txt+0x1a>
mov    -0x10(%rbp),%eax
sub    $0x1,%eax
je     113c <login_err_txt+0x3c>
jmp    112b <login_err_txt+0x2b>
mov    -0x10(%rbp),%eax
sub    $0x2,%eax
je     114c <login_err_txt+0x4c>
jmp    116c <login_err_txt+0x6c>
lea    0xebd(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    1177 <login_err_txt+0x77>
lea    0xed3(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    1177 <login_err_txt+0x77>
lea    0xee8(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    1177 <login_err_txt+0x77>
lea    0xef1(%rip),%rax
mov    %rax,-0x8(%rbp)
mov    -0x8(%rbp),%rax
pop    %rbp
ret

x86 assembly (clang, -O2):
<login_err_txt>:
cmp    $0x2,%edi
ja     1117 <login_err_txt+0x17>
movslq %edi,%rax
lea    0xf65(%rip),%rcx
movslq (%rcx,%rax,4),%rax
add    %rcx,%rax
ret
lea    0xf46(%rip),%rax
ret

LLVM IR (-O0):
@.str = [38 x i8] c"The provided username does not exist.\00"
@.str.1 = [37 x i8] c"The provided password was incorrect.\00"
@.str.2 = [25 x i8] c"The login was a success.\00"
@.str.3 = [16 x i8] c"Uhhh..... yeah.\00"
define i8* @login_err_txt(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 2, label %6
i32 0, label %7
]
5: ; preds = %1
store i8* getelementptr inbounds ([38 x i8], [38 x i8]* @.str, i64 0, i64 0), i8** %2
br label %9
6: ; preds = %1
store i8* getelementptr inbounds ([37 x i8], [37 x i8]* @.str.1, i64 0, i64 0), i8** %2
br label %9
7: ; preds = %1
store i8* getelementptr inbounds ([25 x i8], [25 x i8]* @.str.2, i64 0, i64 0), i8** %2
br label %9
8: ; preds = %1
store i8* getelementptr inbounds ([16 x i8], [16 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 = [38 x i8] c"The provided username does not exist.\00"
@.str.1 = [37 x i8] c"The provided password was incorrect.\00"
@.str.2 = [25 x i8] c"The login was a success.\00"
@.str.3 = [16 x i8] c"Uhhh..... yeah.\00"
@reltable.login_err_txt = [3 x i32] [i32 trunc (i64 sub (i64 ptrtoint ([25 x i8]* @.str.2 to i64), i64 ptrtoint ([3 x i32]* @reltable.login_err_txt to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([38 x i8]* @.str to i64), i64 ptrtoint ([3 x i32]* @reltable.login_err_txt to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([37 x i8]* @.str.1 to i64), i64 ptrtoint ([3 x i32]* @reltable.login_err_txt to i64)) to i32)]
define i8* @login_err_txt(i32 %0) {
%2 = icmp ult i32 %0, 3
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 ([3 x i32]* @reltable.login_err_txt to i8*), i64 %5)
br label %7
7: ; preds = %1, %3
%8 = phi i8* [ %6, %3 ], [ getelementptr inbounds ([16 x i8], [16 x i8]* @.str.3, i64 0, i64 0), %1 ]
ret i8* %8
}