#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 */
char *memory_Malloc(scalar_t__);
char *strcat(char *, char *);
int /*<<< orphan*/ strcpy(char *, char *);
int /*<<< orphan*/ string_StringFree(char *);
scalar_t__ strlen(char *);
char *string_Nconc(char *s1, char *s2) {
  char *dst;
  dst = memory_Malloc(strlen(s1) + strlen(s2) + 1);
  strcpy(dst, s1);
  dst = strcat(dst, s2);
  string_StringFree(s1);
  string_StringFree(s2);
  return dst;
}


x86 assembly (clang, -O0):
<string_Nconc>:
push   %rbp
mov    %rsp,%rbp
sub    $0x20,%rsp
mov    %rdi,-0x8(%rbp)
mov    %rsi,-0x10(%rbp)
mov    -0x8(%rbp),%rdi
call   1060 <strlen@plt>
mov    %rax,-0x20(%rbp)
mov    -0x10(%rbp),%rdi
call   1060 <strlen@plt>
mov    -0x20(%rbp),%rdi
add    %rax,%rdi
add    $0x1,%rdi
call   1030 <memory_Malloc@plt>
mov    %rax,-0x18(%rbp)
mov    -0x18(%rbp),%rdi
mov    -0x8(%rbp),%rsi
call   1040 <strcpy@plt>
mov    -0x18(%rbp),%rdi
mov    -0x10(%rbp),%rsi
call   1070 <strcat@plt>
mov    %rax,-0x18(%rbp)
mov    -0x8(%rbp),%rdi
call   1050 <string_StringFree@plt>
mov    -0x10(%rbp),%rdi
call   1050 <string_StringFree@plt>
mov    -0x18(%rbp),%rax
add    $0x20,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<string_Nconc>:
push   %r15
push   %r14
push   %r12
push   %rbx
push   %rax
mov    %rsi,%r14
mov    %rdi,%r12
call   1060 <strlen@plt>
mov    %rax,%r15
mov    %r14,%rdi
call   1060 <strlen@plt>
lea    (%r15,%rax,1),%rdi
add    $0x1,%rdi
call   1030 <memory_Malloc@plt>
mov    %rax,%rbx
mov    %rax,%rdi
mov    %r12,%rsi
call   1040 <strcpy@plt>
mov    %rbx,%rdi
mov    %r14,%rsi
call   1070 <strcat@plt>
mov    %r12,%rdi
call   1050 <string_StringFree@plt>
mov    %r14,%rdi
call   1050 <string_StringFree@plt>
mov    %rbx,%rax
add    $0x8,%rsp
pop    %rbx
pop    %r12
pop    %r14
pop    %r15
ret

LLVM IR (-O0):
define i8* @string_Nconc(i8* %0, i8* %1) {
%3 = alloca i8*
%4 = alloca i8*
%5 = alloca i8*
store i8* %0, i8** %3
store i8* %1, i8** %4
%6 = load i8*, i8** %3
%7 = call i64 @strlen(i8* %6)
%8 = load i8*, i8** %4
%9 = call i64 @strlen(i8* %8)
%10 = add nsw i64 %7, %9
%11 = add nsw i64 %10, 1
%12 = call i8* @memory_Malloc(i64 %11)
store i8* %12, i8** %5
%13 = load i8*, i8** %5
%14 = load i8*, i8** %3
%15 = call i32 @strcpy(i8* %13, i8* %14)
%16 = load i8*, i8** %5
%17 = load i8*, i8** %4
%18 = call i8* @strcat(i8* %16, i8* %17)
store i8* %18, i8** %5
%19 = load i8*, i8** %3
%20 = call i32 @string_StringFree(i8* %19)
%21 = load i8*, i8** %4
%22 = call i32 @string_StringFree(i8* %21)
%23 = load i8*, i8** %5
ret i8* %23
}

LLVM IR (-O2):
define i8* @string_Nconc(i8* %0, i8* %1) {
%3 = tail call i64 @strlen(i8* dereferenceable(1) %0)
%4 = tail call i64 @strlen(i8* dereferenceable(1) %1)
%5 = add i64 %3, 1
%6 = add i64 %5, %4
%7 = tail call i8* @memory_Malloc(i64 %6)
%8 = tail call i32 @strcpy(i8* %7, i8* %0)
%9 = tail call i8* @strcat(i8* dereferenceable(1) %7, i8* dereferenceable(1) %1)
%10 = tail call i32 @string_StringFree(i8* %0)
%11 = tail call i32 @string_StringFree(i8* %1)
ret i8* %7
}