int months_to_days(int n) {
  switch (n) {
  case 1:
    return 0;
  case 2:
    return 31;
  case 3:
    return 59;
  case 4:
    return 90;
  case 5:
    return 120;
  case 6:
    return 151;
  case 7:
    return 181;
  case 8:
    return 212;
  case 9:
    return 243;
  case 10:
    return 273;
  case 11:
    return 304;
  case 12:
  default:
    return 334;
  }
}


x86 assembly (clang, -O0):
<months_to_days>:
push   %rbp
mov    %rsp,%rbp
mov    %edi,-0x8(%rbp)
mov    -0x8(%rbp),%eax
add    $0xffffffff,%eax
mov    %eax,%ecx
mov    %rcx,-0x10(%rbp)
sub    $0xb,%eax
ja     11b9 <months_to_days+0xb9>
mov    -0x10(%rbp),%rax
lea    0xed9(%rip),%rcx
movslq (%rcx,%rax,4),%rax
add    %rcx,%rax
jmp    *%rax
movl   $0x0,-0x4(%rbp)
jmp    11c0 <months_to_days+0xc0>
movl   $0x1f,-0x4(%rbp)
jmp    11c0 <months_to_days+0xc0>
movl   $0x3b,-0x4(%rbp)
jmp    11c0 <months_to_days+0xc0>
movl   $0x5a,-0x4(%rbp)
jmp    11c0 <months_to_days+0xc0>
movl   $0x78,-0x4(%rbp)
jmp    11c0 <months_to_days+0xc0>
movl   $0x97,-0x4(%rbp)
jmp    11c0 <months_to_days+0xc0>
movl   $0xb5,-0x4(%rbp)
jmp    11c0 <months_to_days+0xc0>
movl   $0xd4,-0x4(%rbp)
jmp    11c0 <months_to_days+0xc0>
movl   $0xf3,-0x4(%rbp)
jmp    11c0 <months_to_days+0xc0>
movl   $0x111,-0x4(%rbp)
jmp    11c0 <months_to_days+0xc0>
movl   $0x130,-0x4(%rbp)
jmp    11c0 <months_to_days+0xc0>
jmp    11b9 <months_to_days+0xb9>
movl   $0x14e,-0x4(%rbp)
mov    -0x4(%rbp),%eax
pop    %rbp
ret

x86 assembly (clang, -O2):
<months_to_days>:
add    $0xffffffff,%edi
mov    $0x14e,%eax
cmp    $0xa,%edi
ja     111a <months_to_days+0x1a>
movslq %edi,%rax
lea    0xee9(%rip),%rcx
mov    (%rcx,%rax,4),%eax
ret

LLVM IR (-O0):
define i32 @months_to_days(i32 %0) {
%2 = alloca i32
%3 = alloca i32
store i32 %0, i32* %3
%4 = load i32, i32* %3
switch i32 %4, label %17 [
i32 1, label %5
i32 2, label %6
i32 3, label %7
i32 4, label %8
i32 5, label %9
i32 6, label %10
i32 7, label %11
i32 8, label %12
i32 9, label %13
i32 10, label %14
i32 11, label %15
i32 12, label %16
]
5: ; preds = %1
store i32 0, i32* %2
br label %18
6: ; preds = %1
store i32 31, i32* %2
br label %18
7: ; preds = %1
store i32 59, i32* %2
br label %18
8: ; preds = %1
store i32 90, i32* %2
br label %18
9: ; preds = %1
store i32 120, i32* %2
br label %18
10: ; preds = %1
store i32 151, i32* %2
br label %18
11: ; preds = %1
store i32 181, i32* %2
br label %18
12: ; preds = %1
store i32 212, i32* %2
br label %18
13: ; preds = %1
store i32 243, i32* %2
br label %18
14: ; preds = %1
store i32 273, i32* %2
br label %18
15: ; preds = %1
store i32 304, i32* %2
br label %18
16: ; preds = %1
br label %17
17: ; preds = %1, %16
store i32 334, i32* %2
br label %18
18: ; preds = %17, %15, %14, %13, %12, %11, %10, %9, %8, %7, %6, %5
%19 = load i32, i32* %2
ret i32 %19
}

LLVM IR (-O2):
@switch.table.months_to_days = [11 x i32] [i32 0, i32 31, i32 59, i32 90, i32 120, i32 151, i32 181, i32 212, i32 243, i32 273, i32 304]
define i32 @months_to_days(i32 %0) {
%2 = add i32 %0, -1
%3 = icmp ult i32 %2, 11
br i1 %3, label %4, label %8
4: ; preds = %1
%5 = sext i32 %2 to i64
%6 = getelementptr inbounds [11 x i32], [11 x i32]* @switch.table.months_to_days, i64 0, i64 %5
%7 = load i32, i32* %6
br label %8
8: ; preds = %1, %4
%9 = phi i32 [ %7, %4 ], [ 334, %1 ]
ret i32 %9
}