#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 scanf(char *, ...);
int getnights(void) {
  int nights;
  printf("How many nights are needed? ");
  while (scanf("%d", &nights) != 1) {
    scanf("%*s");
    printf("Enter an integer\n");
  }
  return nights;
}


x86 assembly (clang, -O0):
<getnights>:
push   %rbp
mov    %rsp,%rbp
sub    $0x10,%rsp
lea    0xed1(%rip),%rdi
call   1030 <printf@plt>
lea    0xee2(%rip),%rdi
lea    -0x4(%rbp),%rsi
mov    $0x0,%al
call   1040 <scanf@plt>
cmp    $0x1,%eax
je     116e <getnights+0x4e>
lea    0xeca(%rip),%rdi
mov    $0x0,%al
call   1040 <scanf@plt>
lea    0xec0(%rip),%rdi
call   1030 <printf@plt>
jmp    1134 <getnights+0x14>
mov    -0x4(%rbp),%eax
add    $0x10,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<getnights>:
push   %r15
push   %r14
push   %r12
push   %rbx
push   %rax
lea    0xec1(%rip),%rdi
call   1040 <printf@plt>
lea    0xed2(%rip),%rdi
lea    0x4(%rsp),%rsi
xor    %eax,%eax
call   1050 <scanf@plt>
cmp    $0x1,%eax
je     11a4 <getnights+0x74>
lea    0xebd(%rip),%r14
lea    0xeba(%rip),%r15
lea    0xeac(%rip),%r12
lea    0x4(%rsp),%rbx
cs nopw 0x0(%rax,%rax,1)
mov    %r14,%rdi
xor    %eax,%eax
call   1050 <scanf@plt>
mov    %r15,%rdi
call   1030 <puts@plt>
mov    %r12,%rdi
mov    %rbx,%rsi
xor    %eax,%eax
call   1050 <scanf@plt>
cmp    $0x1,%eax
jne    1180 <getnights+0x50>
mov    0x4(%rsp),%eax
add    $0x8,%rsp
pop    %rbx
pop    %r12
pop    %r14
pop    %r15
ret

LLVM IR (-O0):
@.str = [29 x i8] c"How many nights are needed? \00"
@.str.1 = [3 x i8] c"%d\00"
@.str.2 = [4 x i8] c"%*s\00"
@.str.3 = [18 x i8] c"Enter an integer\0A\00"
define i32 @getnights() {
%1 = alloca i32
%2 = call i32 @printf(i8* getelementptr inbounds ([29 x i8], [29 x i8]* @.str, i64 0, i64 0))
br label %3
3: ; preds = %6, %0
%4 = call i32 (i8*, ...) @scanf(i8* getelementptr inbounds ([3 x i8], [3 x i8]* @.str.1, i64 0, i64 0), i32* %1)
%5 = icmp ne i32 %4, 1
br i1 %5, label %6, label %9
6: ; preds = %3
%7 = call i32 (i8*, ...) @scanf(i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str.2, i64 0, i64 0))
%8 = call i32 @printf(i8* getelementptr inbounds ([18 x i8], [18 x i8]* @.str.3, i64 0, i64 0))
br label %3
9: ; preds = %3
%10 = load i32, i32* %1
ret i32 %10
}

LLVM IR (-O2):
@.str = [29 x i8] c"How many nights are needed? \00"
@.str.1 = [3 x i8] c"%d\00"
@.str.2 = [4 x i8] c"%*s\00"
@str = [17 x i8] c"Enter an integer\00"
define i32 @getnights() {
%1 = alloca i32
%2 = bitcast i32* %1 to i8*
%3 = tail call i32 @printf(i8* dereferenceable(1) getelementptr inbounds ([29 x i8], [29 x i8]* @.str, i64 0, i64 0))
%4 = call i32 (i8*, ...) @scanf(i8* getelementptr inbounds ([3 x i8], [3 x i8]* @.str.1, i64 0, i64 0), i32* %1)
%5 = icmp eq i32 %4, 1
br i1 %5, label %11, label %6
6: ; preds = %0, %6
%7 = call i32 (i8*, ...) @scanf(i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str.2, i64 0, i64 0))
%8 = call i32 @puts(i8* dereferenceable(1) getelementptr inbounds ([17 x i8], [17 x i8]* @str, i64 0, i64 0))
%9 = call i32 (i8*, ...) @scanf(i8* getelementptr inbounds ([3 x i8], [3 x i8]* @.str.1, i64 0, i64 0), i32* %1)
%10 = icmp eq i32 %9, 1
br i1 %10, label %11, label %6
11: ; preds = %6, %0
%12 = load i32, i32* %1
ret i32 %12
}