#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(void) {
  int sum = 0, n, num = 2;
  printf("Enter how many even natural numbers you want sum up: ");
  scanf("%d", &n);
  for (int i = 0; i < n; i++) {
    sum += num;
    num += 2;
  }
  printf("\nThe sum of given n even natural numbers is %d", sum);
  return 0;
}


x86 assembly (clang, -O0):
<main>:
push   %rbp
mov    %rsp,%rbp
sub    $0x20,%rsp
movl   $0x0,-0x4(%rbp)
movl   $0x0,-0x8(%rbp)
movl   $0x2,-0x10(%rbp)
lea    0xebc(%rip),%rdi
mov    $0x0,%al
call   1030 <printf@plt>
lea    0xf10(%rip),%rdi
lea    -0xc(%rbp),%rsi
call   1040 <scanf@plt>
movl   $0x0,-0x14(%rbp)
mov    -0x14(%rbp),%eax
cmp    -0xc(%rbp),%eax
jge    118e <main+0x6e>
mov    -0x10(%rbp),%eax
add    -0x8(%rbp),%eax
mov    %eax,-0x8(%rbp)
mov    -0x10(%rbp),%eax
add    $0x2,%eax
mov    %eax,-0x10(%rbp)
mov    -0x14(%rbp),%eax
add    $0x1,%eax
mov    %eax,-0x14(%rbp)
jmp    1162 <main+0x42>
mov    -0x8(%rbp),%esi
lea    0xe9e(%rip),%rdi
mov    $0x0,%al
call   1030 <printf@plt>
xor    %eax,%eax
add    $0x20,%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    0xf26(%rip),%rdi
lea    0xc(%rsp),%rsi
call   1040 <scanf@plt>
mov    0xc(%rsp),%eax
test   %eax,%eax
jle    1160 <main+0x40>
lea    -0x1(%rax),%ecx
lea    -0x2(%rax),%edx
imul   %ecx,%edx
and    $0xfffffffe,%edx
lea    (%rdx,%rax,4),%ebx
add    $0xfffffffe,%ebx
lea    0xecf(%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 = [54 x i8] c"Enter how many even natural numbers you want sum up: \00"
@.str.1 = [3 x i8] c"%d\00"
@.str.2 = [47 x i8] c"\0AThe sum of given n even natural numbers is %d\00"
define i32 @main() {
%1 = alloca i32
%2 = alloca i32
%3 = alloca i32
%4 = alloca i32
%5 = alloca i32
store i32 0, i32* %1
store i32 0, i32* %2
store i32 2, i32* %4
%6 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([54 x i8], [54 x i8]* @.str, i64 0, i64 0))
%7 = call i32 @scanf(i8* getelementptr inbounds ([3 x i8], [3 x i8]* @.str.1, i64 0, i64 0), i32* %3)
store i32 0, i32* %5
br label %8
8: ; preds = %18, %0
%9 = load i32, i32* %5
%10 = load i32, i32* %3
%11 = icmp slt i32 %9, %10
br i1 %11, label %12, label %21
12: ; preds = %8
%13 = load i32, i32* %4
%14 = load i32, i32* %2
%15 = add nsw i32 %14, %13
store i32 %15, i32* %2
%16 = load i32, i32* %4
%17 = add nsw i32 %16, 2
store i32 %17, i32* %4
br label %18
18: ; preds = %12
%19 = load i32, i32* %5
%20 = add nsw i32 %19, 1
store i32 %20, i32* %5
br label %8
21: ; preds = %8
%22 = load i32, i32* %2
%23 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([47 x i8], [47 x i8]* @.str.2, i64 0, i64 0), i32 %22)
ret i32 0
}

LLVM IR (-O2):
@.str = [54 x i8] c"Enter how many even natural numbers you want sum up: \00"
@.str.1 = [3 x i8] c"%d\00"
@.str.2 = [47 x i8] c"\0AThe sum of given n even natural numbers is %d\00"
define i32 @main() {
%1 = alloca i32
%2 = bitcast i32* %1 to i8*
%3 = tail call i32 (i8*, ...) @printf(i8* dereferenceable(1) getelementptr inbounds ([54 x i8], [54 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 sgt i32 %5, 0
br i1 %6, label %7, label %15
7: ; preds = %0
%8 = shl i32 %5, 2
%9 = add nsw i32 %5, -1
%10 = add nsw i32 %5, -2
%11 = mul i32 %9, %10
%12 = and i32 %11, -2
%13 = add i32 %8, %12
%14 = add i32 %13, -2
br label %15
15: ; preds = %7, %0
%16 = phi i32 [ 0, %0 ], [ %14, %7 ]
%17 = call i32 (i8*, ...) @printf(i8* dereferenceable(1) getelementptr inbounds ([47 x i8], [47 x i8]* @.str.2, i64 0, i64 0), i32 %16)
ret i32 0
}