void month_Word(int month, char monthConvert[]) {
  int i;
  char monthWords[12][10] = {
      "January", "February", "March",     "April",   "May",      "June",
      "July",    "August",   "Septemper", "October", "November", "December",
  };
  for (i = 0; i < 12; i++) {
    if (month == i + 1)
      strcpy(monthConvert, monthWords[i]);
  }
}


x86 assembly (clang, -O0):
<month_Word>:
push   %rbp
mov    %rsp,%rbp
sub    $0x90,%rsp
mov    %edi,-0x4(%rbp)
mov    %rsi,-0x10(%rbp)
lea    -0x90(%rbp),%rdi
lea    0xec0(%rip),%rsi
mov    $0x78,%edx
call   1040 <memcpy@plt>
movl   $0x0,-0x14(%rbp)
cmpl   $0xc,-0x14(%rbp)
jge    119a <month_Word+0x7a>
mov    -0x4(%rbp),%eax
mov    -0x14(%rbp),%ecx
add    $0x1,%ecx
cmp    %ecx,%eax
jne    1187 <month_Word+0x67>
mov    -0x10(%rbp),%rdi
movslq -0x14(%rbp),%rax
lea    -0x90(%rbp),%rsi
imul   $0xa,%rax,%rax
add    %rax,%rsi
call   1030 <strcpy@plt>
jmp    118c <month_Word+0x6c>
mov    -0x14(%rbp),%eax
add    $0x1,%eax
mov    %eax,-0x14(%rbp)
jmp    1151 <month_Word+0x31>
add    $0x90,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<month_Word>:
sub    $0x78,%rsp
mov    0xf85(%rip),%rax
mov    %rax,0x70(%rsp)
movaps 0xf69(%rip),%xmm0
movaps %xmm0,0x60(%rsp)
movaps 0xf4d(%rip),%xmm0
movaps %xmm0,0x50(%rsp)
movaps 0xf31(%rip),%xmm0
movaps %xmm0,0x40(%rsp)
movaps 0xf15(%rip),%xmm0
movaps %xmm0,0x30(%rsp)
movaps 0xef9(%rip),%xmm0
movaps %xmm0,0x20(%rsp)
movaps 0xedd(%rip),%xmm0
movaps %xmm0,0x10(%rsp)
movaps 0xec1(%rip),%xmm0
movaps %xmm0,(%rsp)
add    $0xffffffff,%edi
cmp    $0xb,%edi
ja     11e4 <month_Word+0xd4>
mov    %rsp,%rax
lea    0xe7b(%rip),%rcx
movslq (%rcx,%rdi,4),%rdx
add    %rcx,%rdx
jmp    *%rdx
lea    0xa(%rsp),%rax
jmp    11d9 <month_Word+0xc9>
lea    0x14(%rsp),%rax
jmp    11d9 <month_Word+0xc9>
lea    0x1e(%rsp),%rax
jmp    11d9 <month_Word+0xc9>
lea    0x28(%rsp),%rax
jmp    11d9 <month_Word+0xc9>
lea    0x32(%rsp),%rax
jmp    11d9 <month_Word+0xc9>
lea    0x3c(%rsp),%rax
jmp    11d9 <month_Word+0xc9>
lea    0x46(%rsp),%rax
jmp    11d9 <month_Word+0xc9>
lea    0x50(%rsp),%rax
jmp    11d9 <month_Word+0xc9>
lea    0x5a(%rsp),%rax
jmp    11d9 <month_Word+0xc9>
lea    0x64(%rsp),%rax
jmp    11d9 <month_Word+0xc9>
lea    0x6e(%rsp),%rax
mov    %rsi,%rdi
mov    %rax,%rsi
call   1030 <strcpy@plt>
add    $0x78,%rsp
ret

LLVM IR (-O0):
@__const.month_Word.monthWords = [12 x [10 x i8]] [[10 x i8] c"January\00\00\00", [10 x i8] c"February\00\00", [10 x i8] c"March\00\00\00\00\00", [10 x i8] c"April\00\00\00\00\00", [10 x i8] c"May\00\00\00\00\00\00\00", [10 x i8] c"June\00\00\00\00\00\00", [10 x i8] c"July\00\00\00\00\00\00", [10 x i8] c"August\00\00\00\00", [10 x i8] c"Septemper\00", [10 x i8] c"October\00\00\00", [10 x i8] c"November\00\00", [10 x i8] c"December\00\00"]
define void @month_Word(i32 %0, i8* %1) {
%3 = alloca i32
%4 = alloca i8*
%5 = alloca i32
%6 = alloca [12 x [10 x i8]]
store i32 %0, i32* %3
store i8* %1, i8** %4
%7 = bitcast [12 x [10 x i8]]* %6 to i8*
store i32 0, i32* %5
br label %8
8: ; preds = %24, %2
%9 = load i32, i32* %5
%10 = icmp slt i32 %9, 12
br i1 %10, label %11, label %27
11: ; preds = %8
%12 = load i32, i32* %3
%13 = load i32, i32* %5
%14 = add nsw i32 %13, 1
%15 = icmp eq i32 %12, %14
br i1 %15, label %16, label %23
16: ; preds = %11
%17 = load i8*, i8** %4
%18 = load i32, i32* %5
%19 = sext i32 %18 to i64
%20 = getelementptr inbounds [12 x [10 x i8]], [12 x [10 x i8]]* %6, i64 0, i64 %19
%21 = getelementptr inbounds [10 x i8], [10 x i8]* %20, i64 0, i64 0
%22 = call i8* @strcpy(i8* %17, i8* %21)
br label %23
23: ; preds = %16, %11
br label %24
24: ; preds = %23
%25 = load i32, i32* %5
%26 = add nsw i32 %25, 1
store i32 %26, i32* %5
br label %8
27: ; preds = %8
ret void
}

LLVM IR (-O2):
@__const.month_Word.monthWords = [12 x [10 x i8]] [[10 x i8] c"January\00\00\00", [10 x i8] c"February\00\00", [10 x i8] c"March\00\00\00\00\00", [10 x i8] c"April\00\00\00\00\00", [10 x i8] c"May\00\00\00\00\00\00\00", [10 x i8] c"June\00\00\00\00\00\00", [10 x i8] c"July\00\00\00\00\00\00", [10 x i8] c"August\00\00\00\00", [10 x i8] c"Septemper\00", [10 x i8] c"October\00\00\00", [10 x i8] c"November\00\00", [10 x i8] c"December\00\00"]
define void @month_Word(i32 %0, i8* %1) {
%3 = alloca [12 x [10 x i8]]
%4 = getelementptr inbounds [12 x [10 x i8]], [12 x [10 x i8]]* %3, i64 0, i64 0, i64 0
switch i32 %0, label %30 [
i32 1, label %27
i32 2, label %5
i32 3, label %7
i32 4, label %9
i32 5, label %11
i32 6, label %13
i32 7, label %15
i32 8, label %17
i32 9, label %19
i32 10, label %21
i32 11, label %23
i32 12, label %25
]
5: ; preds = %2
%6 = getelementptr inbounds [12 x [10 x i8]], [12 x [10 x i8]]* %3, i64 0, i64 1, i64 0
br label %27
7: ; preds = %2
%8 = getelementptr inbounds [12 x [10 x i8]], [12 x [10 x i8]]* %3, i64 0, i64 2, i64 0
br label %27
9: ; preds = %2
%10 = getelementptr inbounds [12 x [10 x i8]], [12 x [10 x i8]]* %3, i64 0, i64 3, i64 0
br label %27
11: ; preds = %2
%12 = getelementptr inbounds [12 x [10 x i8]], [12 x [10 x i8]]* %3, i64 0, i64 4, i64 0
br label %27
13: ; preds = %2
%14 = getelementptr inbounds [12 x [10 x i8]], [12 x [10 x i8]]* %3, i64 0, i64 5, i64 0
br label %27
15: ; preds = %2
%16 = getelementptr inbounds [12 x [10 x i8]], [12 x [10 x i8]]* %3, i64 0, i64 6, i64 0
br label %27
17: ; preds = %2
%18 = getelementptr inbounds [12 x [10 x i8]], [12 x [10 x i8]]* %3, i64 0, i64 7, i64 0
br label %27
19: ; preds = %2
%20 = getelementptr inbounds [12 x [10 x i8]], [12 x [10 x i8]]* %3, i64 0, i64 8, i64 0
br label %27
21: ; preds = %2
%22 = getelementptr inbounds [12 x [10 x i8]], [12 x [10 x i8]]* %3, i64 0, i64 9, i64 0
br label %27
23: ; preds = %2
%24 = getelementptr inbounds [12 x [10 x i8]], [12 x [10 x i8]]* %3, i64 0, i64 10, i64 0
br label %27
25: ; preds = %2
%26 = getelementptr inbounds [12 x [10 x i8]], [12 x [10 x i8]]* %3, i64 0, i64 11, i64 0
br label %27
27: ; preds = %2, %25, %23, %21, %19, %17, %15, %13, %11, %9, %7, %5
%28 = phi i8* [ %6, %5 ], [ %8, %7 ], [ %10, %9 ], [ %12, %11 ], [ %14, %13 ], [ %16, %15 ], [ %18, %17 ], [ %20, %19 ], [ %22, %21 ], [ %24, %23 ], [ %26, %25 ], [ %4, %2 ]
%29 = call i8* @strcpy(i8* dereferenceable(1) %1, i8* %28)
br label %30
30: ; preds = %27, %2
ret void
}