#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 fat_n(int);
int /*<<< orphan*/ printf(char *, ...);
int /*<<< orphan*/ scanf(char *, int *);
int /*<<< orphan*/ system(char *);
int main() {
  int res;
  int n;
  do {
    printf("Inserisci un numero:  ");
    scanf("%d", &n);
  } while (n < 0);
  res = fat_n(n);
  printf("Il fattoriale è:   %d", res);
  system("PAUSE");
}


x86 assembly (clang, -O0):
<main>:
push   %rbp
mov    %rsp,%rbp
sub    $0x10,%rsp
movl   $0x0,-0x4(%rbp)
lea    0xeaa(%rip),%rdi
mov    $0x0,%al
call   1040 <printf@plt>
lea    0xec7(%rip),%rdi
lea    -0xc(%rbp),%rsi
call   1060 <scanf@plt>
cmpl   $0x0,-0xc(%rbp)
jl     114f <main+0xf>
mov    -0xc(%rbp),%edi
call   1050 <fat_n@plt>
mov    %eax,-0x8(%rbp)
mov    -0x8(%rbp),%esi
lea    0xe8b(%rip),%rdi
mov    $0x0,%al
call   1040 <printf@plt>
lea    0xe94(%rip),%rdi
call   1030 <system@plt>
mov    -0x4(%rbp),%eax
add    $0x10,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<main>:
push   %r15
push   %r14
push   %rbx
sub    $0x10,%rsp
lea    0xeb0(%rip),%r14
lea    0xed4(%rip),%r15
lea    0xc(%rsp),%rbx
nopl   0x0(%rax)
mov    %r14,%rdi
xor    %eax,%eax
call   1040 <printf@plt>
mov    %r15,%rdi
mov    %rbx,%rsi
call   1060 <scanf@plt>
mov    0xc(%rsp),%edi
test   %edi,%edi
js     1160 <main+0x20>
call   1050 <fat_n@plt>
lea    0xe8e(%rip),%rdi
mov    %eax,%esi
xor    %eax,%eax
call   1040 <printf@plt>
lea    0xe95(%rip),%rdi
call   1030 <system@plt>
xor    %eax,%eax
add    $0x10,%rsp
pop    %rbx
pop    %r14
pop    %r15
ret

LLVM IR (-O0):
@.str = [23 x i8] c"Inserisci un numero: \00"
@.str.1 = [3 x i8] c"%d\00"
@.str.2 = [23 x i8] c"Il fattoriale \C3\A8: %d\00"
@.str.3 = [6 x i8] c"PAUSE\00"
define i32 @main() {
%1 = alloca i32
%2 = alloca i32
%3 = alloca i32
store i32 0, i32* %1
br label %4
4: ; preds = %7, %0
%5 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([23 x i8], [23 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)
br label %7
7: ; preds = %4
%8 = load i32, i32* %3
%9 = icmp slt i32 %8, 0
br i1 %9, label %4, label %10
10: ; preds = %7
%11 = load i32, i32* %3
%12 = call i32 @fat_n(i32 %11)
store i32 %12, i32* %2
%13 = load i32, i32* %2
%14 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([23 x i8], [23 x i8]* @.str.2, i64 0, i64 0), i32 %13)
%15 = call i32 @system(i8* getelementptr inbounds ([6 x i8], [6 x i8]* @.str.3, i64 0, i64 0))
%16 = load i32, i32* %1
ret i32 %16
}

LLVM IR (-O2):
@.str = [23 x i8] c"Inserisci un numero: \00"
@.str.1 = [3 x i8] c"%d\00"
@.str.2 = [23 x i8] c"Il fattoriale \C3\A8: %d\00"
@.str.3 = [6 x i8] c"PAUSE\00"
define i32 @main() {
%1 = alloca i32
%2 = bitcast i32* %1 to i8*
br label %3
3: ; preds = %3, %0
%4 = call i32 (i8*, ...) @printf(i8* dereferenceable(1) getelementptr inbounds ([23 x i8], [23 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* %1)
%6 = load i32, i32* %1
%7 = icmp slt i32 %6, 0
br i1 %7, label %3, label %8
8: ; preds = %3
%9 = call i32 @fat_n(i32 %6)
%10 = call i32 (i8*, ...) @printf(i8* dereferenceable(1) getelementptr inbounds ([23 x i8], [23 x i8]* @.str.2, i64 0, i64 0), i32 %9)
%11 = call i32 @system(i8* getelementptr inbounds ([6 x i8], [6 x i8]* @.str.3, i64 0, i64 0))
ret i32 0
}