#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*/ putchar(char);
int /*<<< orphan*/ scanf(char *, int *);
int main(void) {
  int no;
  printf("请输入一个正整数;");
  scanf("%d", &no);
  while (no >= 0) {
    printf("%d", no--);
    putchar('\n');
  }
  return (0);
}


x86 assembly (clang, -O0):
<main>:
push   %rbp
mov    %rsp,%rbp
sub    $0x10,%rsp
movl   $0x0,-0x4(%rbp)
lea    0xeba(%rip),%rdi
mov    $0x0,%al
call   1040 <printf@plt>
lea    0xec6(%rip),%rdi
lea    -0x8(%rbp),%rsi
call   1050 <scanf@plt>
cmpl   $0x0,-0x8(%rbp)
jl     118f <main+0x5f>
mov    -0x8(%rbp),%esi
mov    %esi,%eax
add    $0xffffffff,%eax
mov    %eax,-0x8(%rbp)
lea    0xea1(%rip),%rdi
mov    $0x0,%al
call   1040 <printf@plt>
mov    $0xa,%edi
call   1030 <putchar@plt>
jmp    115d <main+0x2d>
xor    %eax,%eax
add    $0x10,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<main>:
push   %rbx
sub    $0x10,%rsp
lea    0xec4(%rip),%rdi
xor    %eax,%eax
call   1040 <printf@plt>
lea    0xed0(%rip),%rdi
lea    0xc(%rsp),%rsi
call   1050 <scanf@plt>
mov    0xc(%rsp),%esi
test   %esi,%esi
js     1193 <main+0x63>
lea    0xeb7(%rip),%rbx
cs nopw 0x0(%rax,%rax,1)
nopl   (%rax)
lea    -0x1(%rsi),%eax
mov    %eax,0xc(%rsp)
mov    %rbx,%rdi
xor    %eax,%eax
call   1040 <printf@plt>
mov    $0xa,%edi
call   1030 <putchar@plt>
mov    0xc(%rsp),%esi
test   %esi,%esi
jns    1170 <main+0x40>
xor    %eax,%eax
add    $0x10,%rsp
pop    %rbx
ret

LLVM IR (-O0):
@.str = [26 x i8] c"\E8\AF\B7\E8\BE\93\E5\85\A5\E4\B8\80\E4\B8\AA\E6\AD\A3\E6\95\B4\E6\95\B0;\00"
@.str.1 = [3 x i8] c"%d\00"
define i32 @main() {
%1 = alloca i32
%2 = alloca i32
store i32 0, i32* %1
%3 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([26 x i8], [26 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* %2)
br label %5
5: ; preds = %8, %0
%6 = load i32, i32* %2
%7 = icmp sge i32 %6, 0
br i1 %7, label %8, label %13
8: ; preds = %5
%9 = load i32, i32* %2
%10 = add nsw i32 %9, -1
store i32 %10, i32* %2
%11 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([3 x i8], [3 x i8]* @.str.1, i64 0, i64 0), i32 %9)
%12 = call i32 @putchar(i8 signext 10)
br label %5
13: ; preds = %5
ret i32 0
}

LLVM IR (-O2):
@.str = [26 x i8] c"\E8\AF\B7\E8\BE\93\E5\85\A5\E4\B8\80\E4\B8\AA\E6\AD\A3\E6\95\B4\E6\95\B0;\00"
@.str.1 = [3 x i8] c"%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 ([26 x i8], [26 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, -1
br i1 %6, label %7, label %14
7: ; preds = %0, %7
%8 = phi i32 [ %12, %7 ], [ %5, %0 ]
%9 = add nsw i32 %8, -1
store i32 %9, i32* %1
%10 = call i32 (i8*, ...) @printf(i8* dereferenceable(1) getelementptr inbounds ([3 x i8], [3 x i8]* @.str.1, i64 0, i64 0), i32 %8)
%11 = call i32 @putchar(i8 signext 10)
%12 = load i32, i32* %1
%13 = icmp sgt i32 %12, -1
br i1 %13, label %7, label %14
14: ; preds = %7, %0
ret i32 0
}