#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 atoi(char *);
int count(int);
int /*<<< orphan*/ printf(char *, ...);
int /*<<< orphan*/ scanf(char *, int *);
int main(int argc, char **argv) {
  int n;
  if (argc < 2) {
    printf("input a number:");
    scanf("%d", &n);
  } else {
    n = atoi(argv[1]);
  }
  printf("%d\n", count(n));
  return 0;
}


x86 assembly (clang, -O0):
<main>:
push   %rbp
mov    %rsp,%rbp
sub    $0x20,%rsp
movl   $0x0,-0x4(%rbp)
mov    %edi,-0x8(%rbp)
mov    %rsi,-0x10(%rbp)
cmpl   $0x2,-0x8(%rbp)
jge    1183 <main+0x43>
lea    0xe99(%rip),%rdi
mov    $0x0,%al
call   1040 <printf@plt>
lea    0xe9b(%rip),%rdi
lea    -0x14(%rbp),%rsi
call   1050 <scanf@plt>
jmp    1193 <main+0x53>
mov    -0x10(%rbp),%rax
mov    0x8(%rax),%rdi
call   1060 <atoi@plt>
mov    %eax,-0x14(%rbp)
mov    -0x14(%rbp),%edi
call   1030 <count@plt>
mov    %eax,%esi
lea    0xe6f(%rip),%rdi
mov    $0x0,%al
call   1040 <printf@plt>
xor    %eax,%eax
add    $0x20,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<main>:
push   %rax
cmp    $0x1,%edi
jg     116b <main+0x2b>
lea    0xeb3(%rip),%rdi
xor    %eax,%eax
call   1040 <printf@plt>
lea    0xeb5(%rip),%rdi
lea    0x4(%rsp),%rsi
call   1050 <scanf@plt>
mov    0x4(%rsp),%edi
jmp    117a <main+0x3a>
mov    0x8(%rsi),%rdi
call   1060 <atoi@plt>
mov    %eax,%edi
mov    %eax,0x4(%rsp)
call   1030 <count@plt>
lea    0xe8d(%rip),%rdi
mov    %eax,%esi
xor    %eax,%eax
call   1040 <printf@plt>
xor    %eax,%eax
pop    %rcx
ret

LLVM IR (-O0):
@.str = [16 x i8] c"input a number:\00"
@.str.1 = [3 x i8] c"%d\00"
@.str.2 = [4 x i8] c"%d\0A\00"
define i32 @main(i32 %0, i8** %1) {
%3 = alloca i32
%4 = alloca i32
%5 = alloca i8**
%6 = alloca i32
store i32 0, i32* %3
store i32 %0, i32* %4
store i8** %1, i8*** %5
%7 = load i32, i32* %4
%8 = icmp slt i32 %7, 2
br i1 %8, label %9, label %12
9: ; preds = %2
%10 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([16 x i8], [16 x i8]* @.str, i64 0, i64 0))
%11 = call i32 @scanf(i8* getelementptr inbounds ([3 x i8], [3 x i8]* @.str.1, i64 0, i64 0), i32* %6)
br label %17
12: ; preds = %2
%13 = load i8**, i8*** %5
%14 = getelementptr inbounds i8*, i8** %13, i64 1
%15 = load i8*, i8** %14
%16 = call i32 @atoi(i8* %15)
store i32 %16, i32* %6
br label %17
17: ; preds = %12, %9
%18 = load i32, i32* %6
%19 = call i32 @count(i32 %18)
%20 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str.2, i64 0, i64 0), i32 %19)
ret i32 0
}

LLVM IR (-O2):
@.str = [16 x i8] c"input a number:\00"
@.str.1 = [3 x i8] c"%d\00"
@.str.2 = [4 x i8] c"%d\0A\00"
define i32 @main(i32 %0, i8** nocapture %1) {
%3 = alloca i32
%4 = bitcast i32* %3 to i8*
%5 = icmp slt i32 %0, 2
br i1 %5, label %6, label %10
6: ; preds = %2
%7 = tail call i32 (i8*, ...) @printf(i8* dereferenceable(1) getelementptr inbounds ([16 x i8], [16 x i8]* @.str, i64 0, i64 0))
%8 = call i32 @scanf(i8* getelementptr inbounds ([3 x i8], [3 x i8]* @.str.1, i64 0, i64 0), i32* %3)
%9 = load i32, i32* %3
br label %14
10: ; preds = %2
%11 = getelementptr inbounds i8*, i8** %1, i64 1
%12 = load i8*, i8** %11
%13 = tail call i32 @atoi(i8* %12)
store i32 %13, i32* %3
br label %14
14: ; preds = %10, %6
%15 = phi i32 [ %13, %10 ], [ %9, %6 ]
%16 = call i32 @count(i32 %15)
%17 = call i32 (i8*, ...) @printf(i8* dereferenceable(1) getelementptr inbounds ([4 x i8], [4 x i8]* @.str.2, i64 0, i64 0), i32 %16)
ret i32 0
}