#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 */
struct sembuf {
  int sem_num;
  int sem_op;
  int /*<<< orphan*/ sem_flg;
};

/* Variables and functions */
int /*<<< orphan*/ SEM_UNDO;
int semop(int, struct sembuf *, int);
int semaphore_down(int semid, int semnum) {
  struct sembuf operations[1];
  operations[0].sem_num = semnum;
  operations[0].sem_op = -1;
  operations[0].sem_flg = SEM_UNDO;
  return semop(semid, operations, 1);
}


x86 assembly (clang, -O0):
<semaphore_down>:
push   %rbp
mov    %rsp,%rbp
sub    $0x20,%rsp
mov    %edi,-0x4(%rbp)
mov    %esi,-0x8(%rbp)
mov    -0x8(%rbp),%eax
mov    %eax,-0x18(%rbp)
movl   $0xffffffff,-0x14(%rbp)
mov    0x2ebe(%rip),%rax
mov    (%rax),%eax
mov    %eax,-0x10(%rbp)
mov    -0x4(%rbp),%edi
lea    -0x18(%rbp),%rsi
mov    $0x1,%edx
call   1030 <semop@plt>
add    $0x20,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<semaphore_down>:
sub    $0x18,%rsp
mov    %esi,0x8(%rsp)
movl   $0xffffffff,0xc(%rsp)
ff
mov    0x2ec9(%rip),%rax
mov    (%rax),%eax
mov    %eax,0x10(%rsp)
lea    0x8(%rsp),%rsi
mov    $0x1,%edx
call   1030 <semop@plt>
add    $0x18,%rsp
ret

LLVM IR (-O0):
%struct.sembuf = type { i32, i32, i32 }
@SEM_UNDO = global i32 0
define i32 @semaphore_down(i32 %0, i32 %1) {
%3 = alloca i32
%4 = alloca i32
%5 = alloca [1 x %struct.sembuf]
store i32 %0, i32* %3
store i32 %1, i32* %4
%6 = load i32, i32* %4
%7 = getelementptr inbounds [1 x %struct.sembuf], [1 x %struct.sembuf]* %5, i64 0, i64 0
%8 = getelementptr inbounds %struct.sembuf, %struct.sembuf* %7, i32 0, i32 0
store i32 %6, i32* %8
%9 = getelementptr inbounds [1 x %struct.sembuf], [1 x %struct.sembuf]* %5, i64 0, i64 0
%10 = getelementptr inbounds %struct.sembuf, %struct.sembuf* %9, i32 0, i32 1
store i32 -1, i32* %10
%11 = load i32, i32* @SEM_UNDO
%12 = getelementptr inbounds [1 x %struct.sembuf], [1 x %struct.sembuf]* %5, i64 0, i64 0
%13 = getelementptr inbounds %struct.sembuf, %struct.sembuf* %12, i32 0, i32 2
store i32 %11, i32* %13
%14 = load i32, i32* %3
%15 = getelementptr inbounds [1 x %struct.sembuf], [1 x %struct.sembuf]* %5, i64 0, i64 0
%16 = call i32 @semop(i32 %14, %struct.sembuf* %15, i32 1)
ret i32 %16
}

LLVM IR (-O2):
%struct.sembuf = type { i32, i32, i32 }
@SEM_UNDO = global i32 0
define i32 @semaphore_down(i32 %0, i32 %1) {
%3 = alloca [1 x %struct.sembuf]
%4 = bitcast [1 x %struct.sembuf]* %3 to i8*
%5 = getelementptr inbounds [1 x %struct.sembuf], [1 x %struct.sembuf]* %3, i64 0, i64 0
%6 = getelementptr inbounds [1 x %struct.sembuf], [1 x %struct.sembuf]* %3, i64 0, i64 0, i32 0
store i32 %1, i32* %6
%7 = getelementptr inbounds [1 x %struct.sembuf], [1 x %struct.sembuf]* %3, i64 0, i64 0, i32 1
store i32 -1, i32* %7
%8 = load i32, i32* @SEM_UNDO
%9 = getelementptr inbounds [1 x %struct.sembuf], [1 x %struct.sembuf]* %3, i64 0, i64 0, i32 2
store i32 %8, i32* %9
%10 = call i32 @semop(i32 %0, %struct.sembuf* %5, i32 1)
ret i32 %10
}