#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 n, number, tri_num;
  printf("What triangular number do you want?\n");
  scanf("%i", &number);
  tri_num = 0;
  for (n = 1; n <= number; ++n) {
    tri_num += n;
  }
  printf("Triangular number %i is %i\n", number, tri_num);
  return 0;
}


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    0xee1(%rip),%rdi
lea    -0xc(%rbp),%rsi
call   1040 <scanf@plt>
movl   $0x0,-0x10(%rbp)
movl   $0x1,-0x8(%rbp)
mov    -0x8(%rbp),%eax
cmp    -0xc(%rbp),%eax
jg     117e <main+0x5e>
mov    -0x8(%rbp),%eax
add    -0x10(%rbp),%eax
mov    %eax,-0x10(%rbp)
mov    -0x8(%rbp),%eax
add    $0x1,%eax
mov    %eax,-0x8(%rbp)
jmp    115b <main+0x3b>
mov    -0xc(%rbp),%esi
mov    -0x10(%rbp),%edx
lea    0xe9d(%rip),%rdi
mov    $0x0,%al
call   1030 <printf@plt>
xor    %eax,%eax
add    $0x10,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<main>:
push   %rax
lea    0xee7(%rip),%rdi
call   1030 <puts@plt>
lea    0xebc(%rip),%rdi
lea    0x4(%rsp),%rsi
call   1050 <scanf@plt>
mov    0x4(%rsp),%esi
test   %esi,%esi
jle    116b <main+0x3b>
lea    -0x1(%rsi),%eax
lea    -0x2(%rsi),%ecx
imul   %rax,%rcx
shr    %rcx
lea    (%rcx,%rsi,2),%edx
add    $0xffffffff,%edx
jmp    116d <main+0x3d>
xor    %edx,%edx
lea    0xe8f(%rip),%rdi
xor    %eax,%eax
call   1040 <printf@plt>
xor    %eax,%eax
pop    %rcx
ret

LLVM IR (-O0):
@.str = [37 x i8] c"What triangular number do you want?\0A\00"
@.str.1 = [3 x i8] c"%i\00"
@.str.2 = [28 x i8] c"Triangular number %i is %i\0A\00"
define i32 @main() {
%1 = alloca i32
%2 = alloca i32
%3 = alloca i32
%4 = alloca i32
store i32 0, i32* %1
%5 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([37 x i8], [37 x i8]* @.str, i64 0, i64 0))
%6 = call i32 @scanf(i8* getelementptr inbounds ([3 x i8], [3 x i8]* @.str.1, i64 0, i64 0), i32* %3)
store i32 0, i32* %4
store i32 1, i32* %2
br label %7
7: ; preds = %15, %0
%8 = load i32, i32* %2
%9 = load i32, i32* %3
%10 = icmp sle i32 %8, %9
br i1 %10, label %11, label %18
11: ; preds = %7
%12 = load i32, i32* %2
%13 = load i32, i32* %4
%14 = add nsw i32 %13, %12
store i32 %14, i32* %4
br label %15
15: ; preds = %11
%16 = load i32, i32* %2
%17 = add nsw i32 %16, 1
store i32 %17, i32* %2
br label %7
18: ; preds = %7
%19 = load i32, i32* %3
%20 = load i32, i32* %4
%21 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([28 x i8], [28 x i8]* @.str.2, i64 0, i64 0), i32 %19, i32 %20)
ret i32 0
}

LLVM IR (-O2):
@.str.1 = [3 x i8] c"%i\00"
@.str.2 = [28 x i8] c"Triangular number %i is %i\0A\00"
@str = [36 x i8] c"What triangular number do you want?\00"
define i32 @main() {
%1 = alloca i32
%2 = bitcast i32* %1 to i8*
%3 = tail call i32 @puts(i8* dereferenceable(1) getelementptr inbounds ([36 x i8], [36 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 slt i32 %5, 1
br i1 %6, label %18, label %7
7: ; preds = %0
%8 = shl nuw i32 %5, 1
%9 = add nsw i32 %5, -1
%10 = zext i32 %9 to i33
%11 = add nsw i32 %5, -2
%12 = zext i32 %11 to i33
%13 = mul i33 %10, %12
%14 = lshr i33 %13, 1
%15 = trunc i33 %14 to i32
%16 = add i32 %8, %15
%17 = add i32 %16, -1
br label %18
18: ; preds = %7, %0
%19 = phi i32 [ 0, %0 ], [ %17, %7 ]
%20 = call i32 (i8*, ...) @printf(i8* dereferenceable(1) getelementptr inbounds ([28 x i8], [28 x i8]* @.str.2, i64 0, i64 0), i32 %5, i32 %19)
ret i32 0
}