#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 *, int *);
int main() {
  int number, digit_sum = 0;
  printf("Enter a number: ");
  scanf("%i", &number);
  while (number != 0) {
    digit_sum += number % 10;
    number /= 10;
  }
  printf("Sum of its digits is %i\n", digit_sum);
  return 0;
}


x86 assembly (clang, -O0):
<main>:
push   %rbp
mov    %rsp,%rbp
sub    $0x10,%rsp
movl   $0x0,-0x4(%rbp)
movl   $0x0,-0xc(%rbp)
lea    0xec3(%rip),%rdi
mov    $0x0,%al
call   1030 <printf@plt>
lea    0xec6(%rip),%rdi
lea    -0x8(%rbp),%rsi
call   1040 <scanf@plt>
cmpl   $0x0,-0x8(%rbp)
je     1182 <main+0x62>
mov    -0x8(%rbp),%eax
mov    $0xa,%ecx
cltd
idiv   %ecx
add    -0xc(%rbp),%edx
mov    %edx,-0xc(%rbp)
mov    -0x8(%rbp),%eax
mov    $0xa,%ecx
cltd
idiv   %ecx
mov    %eax,-0x8(%rbp)
jmp    1154 <main+0x34>
mov    -0xc(%rbp),%esi
lea    0xe88(%rip),%rdi
mov    $0x0,%al
call   1030 <printf@plt>
xor    %eax,%eax
add    $0x10,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<main>:
push   %rbx
sub    $0x10,%rsp
lea    0xed4(%rip),%rdi
xor    %ebx,%ebx
xor    %eax,%eax
call   1030 <printf@plt>
lea    0xed5(%rip),%rdi
lea    0xc(%rsp),%rsi
call   1040 <scanf@plt>
mov    0xc(%rsp),%eax
test   %eax,%eax
je     117f <main+0x5f>
xor    %ebx,%ebx
movslq %eax,%rcx
imul   $0x66666667,%rcx,%rax
mov    %rax,%rdx
shr    $0x3f,%rdx
sar    $0x22,%rax
add    %edx,%eax
lea    (%rax,%rax,1),%edx
lea    (%rdx,%rdx,4),%edx
mov    %ecx,%esi
sub    %edx,%esi
add    %esi,%ebx
add    $0x9,%ecx
cmp    $0x12,%ecx
ja     1150 <main+0x30>
mov    %eax,0xc(%rsp)
lea    0xe8e(%rip),%rdi
mov    %ebx,%esi
xor    %eax,%eax
call   1030 <printf@plt>
xor    %eax,%eax
add    $0x10,%rsp
pop    %rbx
ret

LLVM IR (-O0):
@.str = [17 x i8] c"Enter a number: \00"
@.str.1 = [3 x i8] c"%i\00"
@.str.2 = [25 x i8] c"Sum of its digits is %i\0A\00"
define i32 @main() {
%1 = alloca i32
%2 = alloca i32
%3 = alloca i32
store i32 0, i32* %1
store i32 0, i32* %3
%4 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([17 x i8], [17 x i8]* @.str, i64 0, i64 0))
%5 = call i32 @scanf(i8* getelementptr inbounds ([3 x i8], [3 x i8]* @.str.1, i64 0, i64 0), i32* %2)
br label %6
6: ; preds = %9, %0
%7 = load i32, i32* %2
%8 = icmp ne i32 %7, 0
br i1 %8, label %9, label %16
9: ; preds = %6
%10 = load i32, i32* %2
%11 = srem i32 %10, 10
%12 = load i32, i32* %3
%13 = add nsw i32 %12, %11
store i32 %13, i32* %3
%14 = load i32, i32* %2
%15 = sdiv i32 %14, 10
store i32 %15, i32* %2
br label %6
16: ; preds = %6
%17 = load i32, i32* %3
%18 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([25 x i8], [25 x i8]* @.str.2, i64 0, i64 0), i32 %17)
ret i32 0
}

LLVM IR (-O2):
@.str = [17 x i8] c"Enter a number: \00"
@.str.1 = [3 x i8] c"%i\00"
@.str.2 = [25 x i8] c"Sum of its digits is %i\0A\00"
define i32 @main() {
%1 = alloca i32
%2 = bitcast i32* %1 to i8*
%3 = tail call i32 (i8*, ...) @printf(i8* dereferenceable(1) 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), i32* %1)
%5 = load i32, i32* %1
%6 = icmp eq i32 %5, 0
br i1 %6, label %16, label %7
7: ; preds = %0, %7
%8 = phi i32 [ %11, %7 ], [ 0, %0 ]
%9 = phi i32 [ %12, %7 ], [ %5, %0 ]
%10 = srem i32 %9, 10
%11 = add nsw i32 %8, %10
%12 = sdiv i32 %9, 10
%13 = add i32 %9, 9
%14 = icmp ult i32 %13, 19
br i1 %14, label %15, label %7
15: ; preds = %7
store i32 %12, i32* %1
br label %16
16: ; preds = %15, %0
%17 = phi i32 [ %11, %15 ], [ 0, %0 ]
%18 = call i32 (i8*, ...) @printf(i8* dereferenceable(1) getelementptr inbounds ([25 x i8], [25 x i8]* @.str.2, i64 0, i64 0), i32 %17)
ret i32 0
}