#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 timeval {
  scalar_t__ tv_usec;
  scalar_t__ tv_sec;
};
typedef int /*<<< orphan*/ fd_set;

/* Variables and functions */
int /*<<< orphan*/ FD_SET(int /*<<< orphan*/, int /*<<< orphan*/ *);
int /*<<< orphan*/ FD_ZERO(int /*<<< orphan*/ *);
int /*<<< orphan*/ printf(char *, int);
int select(int, int /*<<< orphan*/ *, int /*<<< orphan*/ *,
           int /*<<< orphan*/ *, struct timeval *);
int main(int argc, char **argv) {
  fd_set s;
  FD_ZERO(&s);
  FD_SET(0, &s);
  struct timeval t;
  t.tv_sec = 0;
  t.tv_usec = 0;
  int ret = select(1, &s, NULL, NULL, &t);
  printf("Return value: %d\n", ret);
  return 0;
}


x86 assembly (clang, -O0):
<main>:
push   %rbp
mov    %rsp,%rbp
sub    $0x30,%rsp
movl   $0x0,-0x4(%rbp)
mov    %edi,-0x8(%rbp)
mov    %rsi,-0x10(%rbp)
lea    -0x14(%rbp),%rdi
call   1040 <FD_ZERO@plt>
xor    %edi,%edi
lea    -0x14(%rbp),%rsi
call   1060 <FD_SET@plt>
movq   $0x0,-0x20(%rbp)
movq   $0x0,-0x28(%rbp)
mov    $0x1,%edi
lea    -0x14(%rbp),%rsi
xor    %eax,%eax
mov    %eax,%ecx
lea    -0x28(%rbp),%r8
mov    %rcx,%rdx
call   1050 <select@plt>
mov    %eax,-0x2c(%rbp)
mov    -0x2c(%rbp),%esi
lea    0xe60(%rip),%rdi
call   1030 <printf@plt>
xor    %eax,%eax
add    $0x30,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<main>:
push   %rbx
sub    $0x20,%rsp
lea    0xc(%rsp),%rbx
mov    %rbx,%rdi
call   1040 <FD_ZERO@plt>
xor    %edi,%edi
mov    %rbx,%rsi
call   1060 <FD_SET@plt>
xorps  %xmm0,%xmm0
movaps %xmm0,0x10(%rsp)
lea    0x10(%rsp),%r8
mov    $0x1,%edi
mov    %rbx,%rsi
xor    %edx,%edx
xor    %ecx,%ecx
call   1050 <select@plt>
lea    0xe7f(%rip),%rdi
mov    %eax,%esi
call   1030 <printf@plt>
xor    %eax,%eax
add    $0x20,%rsp
pop    %rbx
ret

LLVM IR (-O0):
%struct.timeval = type { i64, i64 }
@.str = [18 x i8] c"Return value: %d\0A\00"
define i32 @main(i32 %0, i8** %1) {
%3 = alloca i32
%4 = alloca i32
%5 = alloca i8**
%6 = alloca i32
%7 = alloca %struct.timeval
%8 = alloca i32
store i32 0, i32* %3
store i32 %0, i32* %4
store i8** %1, i8*** %5
%9 = call i32 @FD_ZERO(i32* %6)
%10 = call i32 @FD_SET(i32 0, i32* %6)
%11 = getelementptr inbounds %struct.timeval, %struct.timeval* %7, i32 0, i32 1
store i64 0, i64* %11
%12 = getelementptr inbounds %struct.timeval, %struct.timeval* %7, i32 0, i32 0
store i64 0, i64* %12
%13 = call i32 @select(i32 1, i32* %6, i32* null, i32* null, %struct.timeval* %7)
store i32 %13, i32* %8
%14 = load i32, i32* %8
%15 = call i32 @printf(i8* getelementptr inbounds ([18 x i8], [18 x i8]* @.str, i64 0, i64 0), i32 %14)
ret i32 0
}

LLVM IR (-O2):
%struct.timeval = type { i64, i64 }
@.str = [18 x i8] c"Return value: %d\0A\00"
define i32 @main(i32 %0, i8** nocapture readnone %1) {
%3 = alloca i32
%4 = alloca %struct.timeval
%5 = bitcast i32* %3 to i8*
%6 = call i32 @FD_ZERO(i32* %3)
%7 = call i32 @FD_SET(i32 0, i32* %3)
%8 = bitcast %struct.timeval* %4 to i8*
%9 = bitcast %struct.timeval* %4 to i8*
%10 = call i32 @select(i32 1, i32* %3, i32* null, i32* null, %struct.timeval* %4)
%11 = call i32 @printf(i8* getelementptr inbounds ([18 x i8], [18 x i8]* @.str, i64 0, i64 0), i32 %10)
ret i32 0
}