#define NULL ((void *)0)
typedef unsigned long size_t; // Customize by platform.
typedef long intptr_t;
typedef unsigned long uintptr_t;
typedef long scalar_t__; // Either arithmetic or pointer type.
/* By default, we understand bool (as a convenience). */
typedef int bool;
#define false 0
#define true 1

/* Forward declarations */

/* Type definitions */

/* Variables and functions */
int /*<<< orphan*/ printf(char *, ...);
int /*<<< orphan*/ scanf(char *, char *);
int main() {
  char letter;
  printf("Enter a letter: ");
  scanf("%c", &letter);
  if (letter == 'a' || letter == 'A' || letter == 'e' || letter == 'E' ||
      letter == 'i' || letter == 'I' || letter == 'o' || letter == 'O' ||
      letter == 'u' || letter == 'U')
    printf("%c is a vowel.\n", letter);
  else
    printf("%c is a consonant.\n", letter);
}


x86 assembly (clang, -O0):
<main>:
push   %rbp
mov    %rsp,%rbp
sub    $0x10,%rsp
movl   $0x0,-0x4(%rbp)
lea    0xeca(%rip),%rdi
mov    $0x0,%al
call   1030 <printf@plt>
lea    0xecd(%rip),%rdi
lea    -0x5(%rbp),%rsi
call   1040 <scanf@plt>
movsbl -0x5(%rbp),%eax
cmp    $0x61,%eax
je     11cf <main+0xaf>
movsbl -0x5(%rbp),%eax
cmp    $0x41,%eax
je     11cf <main+0xaf>
movsbl -0x5(%rbp),%eax
cmp    $0x65,%eax
je     11cf <main+0xaf>
movsbl -0x5(%rbp),%eax
cmp    $0x45,%eax
je     11cf <main+0xaf>
movsbl -0x5(%rbp),%eax
cmp    $0x69,%eax
je     11cf <main+0xaf>
movsbl -0x5(%rbp),%eax
cmp    $0x49,%eax
je     11cf <main+0xaf>
movsbl -0x5(%rbp),%eax
cmp    $0x6f,%eax
je     11cf <main+0xaf>
movsbl -0x5(%rbp),%eax
cmp    $0x4f,%eax
je     11cf <main+0xaf>
movsbl -0x5(%rbp),%eax
cmp    $0x75,%eax
je     11cf <main+0xaf>
movsbl -0x5(%rbp),%eax
cmp    $0x55,%eax
jne    11e6 <main+0xc6>
movsbl -0x5(%rbp),%esi
lea    0xe3a(%rip),%rdi
mov    $0x0,%al
call   1030 <printf@plt>
jmp    11f8 <main+0xd8>
movsbl -0x5(%rbp),%esi
lea    0xe33(%rip),%rdi
mov    $0x0,%al
call   1030 <printf@plt>
mov    -0x4(%rbp),%eax
add    $0x10,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<main>:
push   %rax
lea    0xed8(%rip),%rdi
xor    %eax,%eax
call   1030 <printf@plt>
lea    0xedb(%rip),%rdi
lea    0x7(%rsp),%rsi
call   1040 <scanf@plt>
movsbl 0x7(%rsp),%esi
lea    -0x41(%rsi),%eax
cmp    $0x34,%al
ja     1171 <main+0x51>
movzbl %al,%eax
movabs $0x10411100104111,%rcx
bt     %rax,%rcx
jae    1171 <main+0x51>
lea    0xeae(%rip),%rdi
xor    %eax,%eax
call   1030 <printf@plt>
xor    %eax,%eax
pop    %rcx
ret
lea    0xeac(%rip),%rdi
jmp    1166 <main+0x46>

LLVM IR (-O0):
@.str = [17 x i8] c"Enter a letter: \00"
@.str.1 = [3 x i8] c"%c\00"
@.str.2 = [16 x i8] c"%c is a vowel.\0A\00"
@.str.3 = [20 x i8] c"%c is a consonant.\0A\00"
define i32 @main() {
%1 = alloca i32
%2 = alloca i8
store i32 0, i32* %1
%3 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([17 x i8], [17 x i8]* @.str, i64 0, i64 0))
%4 = call i32 @scanf(i8* getelementptr inbounds ([3 x i8], [3 x i8]* @.str.1, i64 0, i64 0), i8* %2)
%5 = load i8, i8* %2
%6 = sext i8 %5 to i32
%7 = icmp eq i32 %6, 97
br i1 %7, label %44, label %8
8: ; preds = %0
%9 = load i8, i8* %2
%10 = sext i8 %9 to i32
%11 = icmp eq i32 %10, 65
br i1 %11, label %44, label %12
12: ; preds = %8
%13 = load i8, i8* %2
%14 = sext i8 %13 to i32
%15 = icmp eq i32 %14, 101
br i1 %15, label %44, label %16
16: ; preds = %12
%17 = load i8, i8* %2
%18 = sext i8 %17 to i32
%19 = icmp eq i32 %18, 69
br i1 %19, label %44, label %20
20: ; preds = %16
%21 = load i8, i8* %2
%22 = sext i8 %21 to i32
%23 = icmp eq i32 %22, 105
br i1 %23, label %44, label %24
24: ; preds = %20
%25 = load i8, i8* %2
%26 = sext i8 %25 to i32
%27 = icmp eq i32 %26, 73
br i1 %27, label %44, label %28
28: ; preds = %24
%29 = load i8, i8* %2
%30 = sext i8 %29 to i32
%31 = icmp eq i32 %30, 111
br i1 %31, label %44, label %32
32: ; preds = %28
%33 = load i8, i8* %2
%34 = sext i8 %33 to i32
%35 = icmp eq i32 %34, 79
br i1 %35, label %44, label %36
36: ; preds = %32
%37 = load i8, i8* %2
%38 = sext i8 %37 to i32
%39 = icmp eq i32 %38, 117
br i1 %39, label %44, label %40
40: ; preds = %36
%41 = load i8, i8* %2
%42 = sext i8 %41 to i32
%43 = icmp eq i32 %42, 85
br i1 %43, label %44, label %48
44: ; preds = %40, %36, %32, %28, %24, %20, %16, %12, %8, %0
%45 = load i8, i8* %2
%46 = sext i8 %45 to i32
%47 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([16 x i8], [16 x i8]* @.str.2, i64 0, i64 0), i32 %46)
br label %52
48: ; preds = %40
%49 = load i8, i8* %2
%50 = sext i8 %49 to i32
%51 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([20 x i8], [20 x i8]* @.str.3, i64 0, i64 0), i32 %50)
br label %52
52: ; preds = %48, %44
%53 = load i32, i32* %1
ret i32 %53
}

LLVM IR (-O2):
@.str = [17 x i8] c"Enter a letter: \00"
@.str.1 = [3 x i8] c"%c\00"
@.str.2 = [16 x i8] c"%c is a vowel.\0A\00"
@.str.3 = [20 x i8] c"%c is a consonant.\0A\00"
define i32 @main() {
%1 = alloca i8
%2 = tail call i32 (i8*, ...) @printf(i8* dereferenceable(1) getelementptr inbounds ([17 x i8], [17 x i8]* @.str, i64 0, i64 0))
%3 = call i32 @scanf(i8* getelementptr inbounds ([3 x i8], [3 x i8]* @.str.1, i64 0, i64 0), i8* %1)
%4 = load i8, i8* %1
switch i8 %4, label %5 [
i8 117, label %6
i8 111, label %6
i8 105, label %6
i8 101, label %6
i8 97, label %6
i8 85, label %6
i8 79, label %6
i8 73, label %6
i8 69, label %6
i8 65, label %6
]
5: ; preds = %0
br label %6
6: ; preds = %0, %0, %0, %0, %0, %0, %0, %0, %0, %0, %5
%7 = phi i8* [ getelementptr inbounds ([20 x i8], [20 x i8]* @.str.3, i64 0, i64 0), %5 ], [ getelementptr inbounds ([16 x i8], [16 x i8]* @.str.2, i64 0, i64 0), %0 ], [ getelementptr inbounds ([16 x i8], [16 x i8]* @.str.2, i64 0, i64 0), %0 ], [ getelementptr inbounds ([16 x i8], [16 x i8]* @.str.2, i64 0, i64 0), %0 ], [ getelementptr inbounds ([16 x i8], [16 x i8]* @.str.2, i64 0, i64 0), %0 ], [ getelementptr inbounds ([16 x i8], [16 x i8]* @.str.2, i64 0, i64 0), %0 ], [ getelementptr inbounds ([16 x i8], [16 x i8]* @.str.2, i64 0, i64 0), %0 ], [ getelementptr inbounds ([16 x i8], [16 x i8]* @.str.2, i64 0, i64 0), %0 ], [ getelementptr inbounds ([16 x i8], [16 x i8]* @.str.2, i64 0, i64 0), %0 ], [ getelementptr inbounds ([16 x i8], [16 x i8]* @.str.2, i64 0, i64 0), %0 ], [ getelementptr inbounds ([16 x i8], [16 x i8]* @.str.2, i64 0, i64 0), %0 ]
%8 = sext i8 %4 to i32
%9 = call i32 (i8*, ...) @printf(i8* dereferenceable(1) %7, i32 %8)
ret i32 0
}