#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*/ strcat(char *, char *);
int /*<<< orphan*/ strcpy(char *, char *);
scalar_t__ strlen(char *);
char *append(char *input_str, char *append_str) {
  char *output_str;
  int malloc_length = (int)strlen(input_str) + (int)strlen(append_str);
  output_str = (char *)malloc(sizeof(char) * (malloc_length + 1));
  strcpy(output_str, input_str);
  strcat(output_str, append_str);
  output_str[malloc_length] = 0;
  return output_str;
}


x86 assembly (clang, -O0):
<append>:
push   %rbp
mov    %rsp,%rbp
sub    $0x20,%rsp
mov    %rdi,-0x8(%rbp)
mov    %rsi,-0x10(%rbp)
mov    -0x8(%rbp),%rdi
call   1040 <strlen@plt>
mov    %eax,-0x20(%rbp)
mov    -0x10(%rbp),%rdi
call   1040 <strlen@plt>
mov    %rax,%rcx
mov    -0x20(%rbp),%eax
add    %ecx,%eax
mov    %eax,-0x1c(%rbp)
mov    -0x1c(%rbp),%eax
add    $0x1,%eax
cltq
shl    $0x0,%rax
mov    %eax,%edi
call   1050 <malloc@plt>
mov    %rax,-0x18(%rbp)
mov    -0x18(%rbp),%rdi
mov    -0x8(%rbp),%rsi
call   1030 <strcpy@plt>
mov    -0x18(%rbp),%rdi
mov    -0x10(%rbp),%rsi
call   1060 <strcat@plt>
mov    -0x18(%rbp),%rax
movslq -0x1c(%rbp),%rcx
movb   $0x0,(%rax,%rcx,1)
mov    -0x18(%rbp),%rax
add    $0x20,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<append>:
push   %rbp
push   %r15
push   %r14
push   %rbx
push   %rax
mov    %rsi,%r14
mov    %rdi,%r15
call   1040 <strlen@plt>
mov    %rax,%rbx
mov    %r14,%rdi
call   1040 <strlen@plt>
lea    (%rax,%rbx,1),%ebp
lea    (%rax,%rbx,1),%edi
add    $0x1,%edi
call   1050 <malloc@plt>
mov    %rax,%rbx
mov    %rax,%rdi
mov    %r15,%rsi
call   1030 <strcpy@plt>
mov    %rbx,%rdi
mov    %r14,%rsi
call   1060 <strcat@plt>
movslq %ebp,%rax
movb   $0x0,(%rbx,%rax,1)
mov    %rbx,%rax
add    $0x8,%rsp
pop    %rbx
pop    %r14
pop    %r15
pop    %rbp
ret

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

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