char *mystery5(int x) {
  if (x == 6)
    return "E";
  else if (x == 7)
    return "D";
  else if (x == 8)
    return "C";
  else if (x == 9)
    return "B";
  else
    return "A";
}


x86 assembly (clang, -O0):
<mystery5>:
push   %rbp
mov    %rsp,%rbp
mov    %edi,-0xc(%rbp)
cmpl   $0x6,-0xc(%rbp)
jne    1121 <mystery5+0x21>
lea    0xee8(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    117a <mystery5+0x7a>
cmpl   $0x7,-0xc(%rbp)
jne    113b <mystery5+0x3b>
lea    0xed0(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    117a <mystery5+0x7a>
cmpl   $0x8,-0xc(%rbp)
jne    1155 <mystery5+0x55>
lea    0xeb8(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    117a <mystery5+0x7a>
cmpl   $0x9,-0xc(%rbp)
jne    116f <mystery5+0x6f>
lea    0xea0(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    117a <mystery5+0x7a>
lea    0xe92(%rip),%rax
mov    %rax,-0x8(%rbp)
mov    -0x8(%rbp),%rax
pop    %rbp
ret

x86 assembly (clang, -O2):
<mystery5>:
add    $0xfffffffa,%edi
cmp    $0x3,%edi
ja     111a <mystery5+0x1a>
movslq %edi,%rax
lea    0xefa(%rip),%rcx
movslq (%rcx,%rax,4),%rax
add    %rcx,%rax
ret
lea    0xee7(%rip),%rax
ret

LLVM IR (-O0):
@.str = [2 x i8] c"E\00"
@.str.1 = [2 x i8] c"D\00"
@.str.2 = [2 x i8] c"C\00"
@.str.3 = [2 x i8] c"B\00"
@.str.4 = [2 x i8] c"A\00"
define i8* @mystery5(i32 %0) {
%2 = alloca i8*
%3 = alloca i32
store i32 %0, i32* %3
%4 = load i32, i32* %3
%5 = icmp eq i32 %4, 6
br i1 %5, label %6, label %7
6: ; preds = %1
store i8* getelementptr inbounds ([2 x i8], [2 x i8]* @.str, i64 0, i64 0), i8** %2
br label %20
7: ; preds = %1
%8 = load i32, i32* %3
%9 = icmp eq i32 %8, 7
br i1 %9, label %10, label %11
10: ; preds = %7
store i8* getelementptr inbounds ([2 x i8], [2 x i8]* @.str.1, i64 0, i64 0), i8** %2
br label %20
11: ; preds = %7
%12 = load i32, i32* %3
%13 = icmp eq i32 %12, 8
br i1 %13, label %14, label %15
14: ; preds = %11
store i8* getelementptr inbounds ([2 x i8], [2 x i8]* @.str.2, i64 0, i64 0), i8** %2
br label %20
15: ; preds = %11
%16 = load i32, i32* %3
%17 = icmp eq i32 %16, 9
br i1 %17, label %18, label %19
18: ; preds = %15
store i8* getelementptr inbounds ([2 x i8], [2 x i8]* @.str.3, i64 0, i64 0), i8** %2
br label %20
19: ; preds = %15
store i8* getelementptr inbounds ([2 x i8], [2 x i8]* @.str.4, i64 0, i64 0), i8** %2
br label %20
20: ; preds = %19, %18, %14, %10, %6
%21 = load i8*, i8** %2
ret i8* %21
}

LLVM IR (-O2):
@.str = [2 x i8] c"E\00"
@.str.1 = [2 x i8] c"D\00"
@.str.2 = [2 x i8] c"C\00"
@.str.3 = [2 x i8] c"B\00"
@.str.4 = [2 x i8] c"A\00"
@reltable.mystery5 = [4 x i32] [i32 trunc (i64 sub (i64 ptrtoint ([2 x i8]* @.str to i64), i64 ptrtoint ([4 x i32]* @reltable.mystery5 to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([2 x i8]* @.str.1 to i64), i64 ptrtoint ([4 x i32]* @reltable.mystery5 to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([2 x i8]* @.str.2 to i64), i64 ptrtoint ([4 x i32]* @reltable.mystery5 to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([2 x i8]* @.str.3 to i64), i64 ptrtoint ([4 x i32]* @reltable.mystery5 to i64)) to i32)]
define i8* @mystery5(i32 %0) {
%2 = add i32 %0, -6
%3 = icmp ult i32 %2, 4
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 ([4 x i32]* @reltable.mystery5 to i8*), i64 %6)
br label %8
8: ; preds = %1, %4
%9 = phi i8* [ %7, %4 ], [ getelementptr inbounds ([2 x i8], [2 x i8]* @.str.4, i64 0, i64 0), %1 ]
ret i8* %9
}