#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 */
scalar_t__ malloc(int);
int /*<<< orphan*/ strcpy(char *, char const *);
int strlen(char const *);
char *cat(const char *id, const char *addr) {
  int len_id = strlen(id);
  int sz = len_id + strlen(addr) + 2;
  char *res = (char *)malloc(sz);
  strcpy(res, id);
  res[len_id] = '@';
  strcpy(res + len_id + 1, addr);
  res[sz - 1] = 0;
  return res;
}


x86 assembly (clang, -O0):
<cat>:
push   %rbp
mov    %rsp,%rbp
sub    $0x30,%rsp
mov    %rdi,-0x8(%rbp)
mov    %rsi,-0x10(%rbp)
mov    -0x8(%rbp),%rdi
call   1040 <strlen@plt>
mov    %eax,-0x14(%rbp)
mov    -0x14(%rbp),%eax
mov    %eax,-0x24(%rbp)
mov    -0x10(%rbp),%rdi
call   1040 <strlen@plt>
mov    %eax,%ecx
mov    -0x24(%rbp),%eax
add    %ecx,%eax
add    $0x2,%eax
mov    %eax,-0x18(%rbp)
mov    -0x18(%rbp),%edi
call   1050 <malloc@plt>
mov    %rax,-0x20(%rbp)
mov    -0x20(%rbp),%rdi
mov    -0x8(%rbp),%rsi
call   1030 <strcpy@plt>
mov    -0x20(%rbp),%rax
movslq -0x14(%rbp),%rcx
movb   $0x40,(%rax,%rcx,1)
mov    -0x20(%rbp),%rdi
movslq -0x14(%rbp),%rax
add    %rax,%rdi
add    $0x1,%rdi
mov    -0x10(%rbp),%rsi
call   1030 <strcpy@plt>
mov    -0x20(%rbp),%rax
mov    -0x18(%rbp),%ecx
sub    $0x1,%ecx
movslq %ecx,%rcx
movb   $0x0,(%rax,%rcx,1)
mov    -0x20(%rbp),%rax
add    $0x30,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<cat>:
push   %rbp
push   %r15
push   %r14
push   %r12
push   %rbx
mov    %rsi,%r14
mov    %rdi,%r15
call   1040 <strlen@plt>
mov    %eax,%r12d
mov    %r14,%rdi
call   1040 <strlen@plt>
lea    (%rax,%r12,1),%edi
add    $0x2,%edi
mov    %eax,%ebp
add    %r12d,%ebp
call   1050 <malloc@plt>
mov    %rax,%rbx
mov    %rax,%rdi
mov    %r15,%rsi
call   1030 <strcpy@plt>
movslq %r12d,%rax
movb   $0x40,(%rbx,%rax,1)
lea    (%rbx,%rax,1),%rdi
add    $0x1,%rdi
mov    %r14,%rsi
call   1030 <strcpy@plt>
movslq %ebp,%rax
movb   $0x0,0x1(%rax,%rbx,1)
mov    %rbx,%rax
pop    %rbx
pop    %r12
pop    %r14
pop    %r15
pop    %rbp
ret

LLVM IR (-O0):
define i8* @cat(i8* %0, i8* %1) {
%3 = alloca i8*
%4 = alloca i8*
%5 = alloca i32
%6 = alloca i32
%7 = alloca i8*
store i8* %0, i8** %3
store i8* %1, i8** %4
%8 = load i8*, i8** %3
%9 = call i32 @strlen(i8* %8)
store i32 %9, i32* %5
%10 = load i32, i32* %5
%11 = load i8*, i8** %4
%12 = call i32 @strlen(i8* %11)
%13 = add nsw i32 %10, %12
%14 = add nsw i32 %13, 2
store i32 %14, i32* %6
%15 = load i32, i32* %6
%16 = call i64 @malloc(i32 %15)
%17 = inttoptr i64 %16 to i8*
store i8* %17, i8** %7
%18 = load i8*, i8** %7
%19 = load i8*, i8** %3
%20 = call i32 @strcpy(i8* %18, i8* %19)
%21 = load i8*, i8** %7
%22 = load i32, i32* %5
%23 = sext i32 %22 to i64
%24 = getelementptr inbounds i8, i8* %21, i64 %23
store i8 64, i8* %24
%25 = load i8*, i8** %7
%26 = load i32, i32* %5
%27 = sext i32 %26 to i64
%28 = getelementptr inbounds i8, i8* %25, i64 %27
%29 = getelementptr inbounds i8, i8* %28, i64 1
%30 = load i8*, i8** %4
%31 = call i32 @strcpy(i8* %29, i8* %30)
%32 = load i8*, i8** %7
%33 = load i32, i32* %6
%34 = sub nsw i32 %33, 1
%35 = sext i32 %34 to i64
%36 = getelementptr inbounds i8, i8* %32, i64 %35
store i8 0, i8* %36
%37 = load i8*, i8** %7
ret i8* %37
}

LLVM IR (-O2):
define i8* @cat(i8* %0, i8* %1) {
%3 = tail call i32 @strlen(i8* %0)
%4 = tail call i32 @strlen(i8* %1)
%5 = add nsw i32 %4, %3
%6 = add nsw i32 %5, 2
%7 = tail call i64 @malloc(i32 %6)
%8 = inttoptr i64 %7 to i8*
%9 = tail call i32 @strcpy(i8* %8, i8* %0)
%10 = sext i32 %3 to i64
%11 = getelementptr inbounds i8, i8* %8, i64 %10
store i8 64, i8* %11
%12 = getelementptr inbounds i8, i8* %11, i64 1
%13 = tail call i32 @strcpy(i8* %12, i8* %1)
%14 = add nsw i32 %5, 1
%15 = sext i32 %14 to i64
%16 = getelementptr inbounds i8, i8* %8, i64 %15
store i8 0, i8* %16
ret i8* %8
}