#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 */
typedef int uint64_t;

/* Variables and functions */
void write_u64_be(unsigned char *buf, uint64_t n) {
  buf[0] = n >> 56 & 0xff;
  buf[1] = n >> 48 & 0xff;
  buf[2] = n >> 40 & 0xff;
  buf[3] = n >> 32 & 0xff;
  buf[4] = n >> 24 & 0xff;
  buf[5] = n >> 16 & 0xff;
  buf[6] = n >> 8 & 0xff;
  buf[7] = n & 0xff;
}


x86 assembly (clang, -O0):
<write_u64_be>:
push   %rbp
mov    %rsp,%rbp
mov    %rdi,-0x8(%rbp)
mov    %esi,-0xc(%rbp)
mov    -0xc(%rbp),%eax
mov    $0x38,%ecx
sar    %cl,%eax
and    $0xff,%eax
mov    %al,%cl
mov    -0x8(%rbp),%rax
mov    %cl,(%rax)
mov    -0xc(%rbp),%eax
mov    $0x30,%ecx
sar    %cl,%eax
and    $0xff,%eax
mov    %al,%cl
mov    -0x8(%rbp),%rax
mov    %cl,0x1(%rax)
mov    -0xc(%rbp),%eax
mov    $0x28,%ecx
sar    %cl,%eax
and    $0xff,%eax
mov    %al,%cl
mov    -0x8(%rbp),%rax
mov    %cl,0x2(%rax)
mov    -0xc(%rbp),%eax
mov    $0x20,%ecx
sar    %cl,%eax
and    $0xff,%eax
mov    %al,%cl
mov    -0x8(%rbp),%rax
mov    %cl,0x3(%rax)
mov    -0xc(%rbp),%eax
sar    $0x18,%eax
and    $0xff,%eax
mov    %al,%cl
mov    -0x8(%rbp),%rax
mov    %cl,0x4(%rax)
mov    -0xc(%rbp),%eax
sar    $0x10,%eax
and    $0xff,%eax
mov    %al,%cl
mov    -0x8(%rbp),%rax
mov    %cl,0x5(%rax)
mov    -0xc(%rbp),%eax
sar    $0x8,%eax
and    $0xff,%eax
mov    %al,%cl
mov    -0x8(%rbp),%rax
mov    %cl,0x6(%rax)
mov    -0xc(%rbp),%eax
and    $0xff,%eax
mov    %al,%cl
mov    -0x8(%rbp),%rax
mov    %cl,0x7(%rax)
pop    %rbp
ret

x86 assembly (clang, -O2):
<write_u64_be>:
bswap  %esi
mov    %esi,0x4(%rdi)
ret

LLVM IR (-O0):
define void @write_u64_be(i8* %0, i32 %1) {
%3 = alloca i8*
%4 = alloca i32
store i8* %0, i8** %3
store i32 %1, i32* %4
%5 = load i32, i32* %4
%6 = ashr i32 %5, 56
%7 = and i32 %6, 255
%8 = trunc i32 %7 to i8
%9 = load i8*, i8** %3
%10 = getelementptr inbounds i8, i8* %9, i64 0
store i8 %8, i8* %10
%11 = load i32, i32* %4
%12 = ashr i32 %11, 48
%13 = and i32 %12, 255
%14 = trunc i32 %13 to i8
%15 = load i8*, i8** %3
%16 = getelementptr inbounds i8, i8* %15, i64 1
store i8 %14, i8* %16
%17 = load i32, i32* %4
%18 = ashr i32 %17, 40
%19 = and i32 %18, 255
%20 = trunc i32 %19 to i8
%21 = load i8*, i8** %3
%22 = getelementptr inbounds i8, i8* %21, i64 2
store i8 %20, i8* %22
%23 = load i32, i32* %4
%24 = ashr i32 %23, 32
%25 = and i32 %24, 255
%26 = trunc i32 %25 to i8
%27 = load i8*, i8** %3
%28 = getelementptr inbounds i8, i8* %27, i64 3
store i8 %26, i8* %28
%29 = load i32, i32* %4
%30 = ashr i32 %29, 24
%31 = and i32 %30, 255
%32 = trunc i32 %31 to i8
%33 = load i8*, i8** %3
%34 = getelementptr inbounds i8, i8* %33, i64 4
store i8 %32, i8* %34
%35 = load i32, i32* %4
%36 = ashr i32 %35, 16
%37 = and i32 %36, 255
%38 = trunc i32 %37 to i8
%39 = load i8*, i8** %3
%40 = getelementptr inbounds i8, i8* %39, i64 5
store i8 %38, i8* %40
%41 = load i32, i32* %4
%42 = ashr i32 %41, 8
%43 = and i32 %42, 255
%44 = trunc i32 %43 to i8
%45 = load i8*, i8** %3
%46 = getelementptr inbounds i8, i8* %45, i64 6
store i8 %44, i8* %46
%47 = load i32, i32* %4
%48 = and i32 %47, 255
%49 = trunc i32 %48 to i8
%50 = load i8*, i8** %3
%51 = getelementptr inbounds i8, i8* %50, i64 7
store i8 %49, i8* %51
ret void
}

LLVM IR (-O2):
define void @write_u64_be(i8* nocapture writeonly %0, i32 %1) {
%3 = lshr i32 %1, 24
%4 = trunc i32 %3 to i8
%5 = getelementptr inbounds i8, i8* %0, i64 4
store i8 %4, i8* %5
%6 = lshr i32 %1, 16
%7 = trunc i32 %6 to i8
%8 = getelementptr inbounds i8, i8* %0, i64 5
store i8 %7, i8* %8
%9 = lshr i32 %1, 8
%10 = trunc i32 %9 to i8
%11 = getelementptr inbounds i8, i8* %0, i64 6
store i8 %10, i8* %11
%12 = trunc i32 %1 to i8
%13 = getelementptr inbounds i8, i8* %0, i64 7
store i8 %12, i8* %13
ret void
}