#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 */
int /*<<< orphan*/ fprintf(int /*<<< orphan*/, char *);
char *malloc(int);
int /*<<< orphan*/ stderr;
int /*<<< orphan*/ strcat(char *, char *);
int strlen(char *);
char *appendString(char *dest, char *src) {
  char *newString;
  int newStringLength = strlen(dest) + strlen(src) + 1;
  if ((newString = malloc(newStringLength)) == NULL) {
    fprintf(stderr, "malloc failed\n");
    return NULL;
  }
  newString[0] = '\x00';
  strcat(newString, dest);
  strcat(newString, src);
  return newString;
}


x86 assembly (clang, -O0):
<appendString>:
push   %rbp
mov    %rsp,%rbp
sub    $0x30,%rsp
mov    %rdi,-0x10(%rbp)
mov    %rsi,-0x18(%rbp)
mov    -0x10(%rbp),%rdi
call   1030 <strlen@plt>
mov    %eax,-0x28(%rbp)
mov    -0x18(%rbp),%rdi
call   1030 <strlen@plt>
mov    %eax,%ecx
mov    -0x28(%rbp),%eax
add    %ecx,%eax
add    $0x1,%eax
mov    %eax,-0x24(%rbp)
mov    -0x24(%rbp),%edi
call   1050 <malloc@plt>
mov    %rax,-0x20(%rbp)
cmp    $0x0,%rax
jne    11aa <appendString+0x6a>
mov    0x2e51(%rip),%rax
mov    (%rax),%edi
lea    0xe68(%rip),%rsi
call   1040 <fprintf@plt>
movq   $0x0,-0x8(%rbp)
jmp    11d3 <appendString+0x93>
mov    -0x20(%rbp),%rax
movb   $0x0,(%rax)
mov    -0x20(%rbp),%rdi
mov    -0x10(%rbp),%rsi
call   1060 <strcat@plt>
mov    -0x20(%rbp),%rdi
mov    -0x18(%rbp),%rsi
call   1060 <strcat@plt>
mov    -0x20(%rbp),%rax
mov    %rax,-0x8(%rbp)
mov    -0x8(%rbp),%rax
add    $0x30,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<appendString>:
push   %r15
push   %r14
push   %rbx
mov    %rsi,%r14
mov    %rdi,%r15
call   1030 <strlen@plt>
mov    %eax,%ebx
mov    %r14,%rdi
call   1030 <strlen@plt>
lea    (%rbx,%rax,1),%edi
add    $0x1,%edi
call   1050 <malloc@plt>
mov    %rax,%rbx
test   %rax,%rax
je     1188 <appendString+0x48>
movb   $0x0,(%rbx)
mov    %rbx,%rdi
mov    %r15,%rsi
call   1060 <strcat@plt>
mov    %rbx,%rdi
mov    %r14,%rsi
call   1060 <strcat@plt>
jmp    119d <appendString+0x5d>
mov    0x2e51(%rip),%rax
mov    (%rax),%edi
lea    0xe68(%rip),%rsi
call   1040 <fprintf@plt>
mov    %rbx,%rax
pop    %rbx
pop    %r14
pop    %r15
ret

LLVM IR (-O0):
@stderr = global i32 0
@.str = [15 x i8] c"malloc failed\0A\00"
define i8* @appendString(i8* %0, i8* %1) {
%3 = alloca i8*
%4 = alloca i8*
%5 = alloca i8*
%6 = alloca i8*
%7 = alloca i32
store i8* %0, i8** %4
store i8* %1, i8** %5
%8 = load i8*, i8** %4
%9 = call i32 @strlen(i8* %8)
%10 = load i8*, i8** %5
%11 = call i32 @strlen(i8* %10)
%12 = add nsw i32 %9, %11
%13 = add nsw i32 %12, 1
store i32 %13, i32* %7
%14 = load i32, i32* %7
%15 = call i8* @malloc(i32 %14)
store i8* %15, i8** %6
%16 = icmp eq i8* %15, null
br i1 %16, label %17, label %20
17: ; preds = %2
%18 = load i32, i32* @stderr
%19 = call i32 @fprintf(i32 %18, i8* getelementptr inbounds ([15 x i8], [15 x i8]* @.str, i64 0, i64 0))
store i8* null, i8** %3
br label %30
20: ; preds = %2
%21 = load i8*, i8** %6
%22 = getelementptr inbounds i8, i8* %21, i64 0
store i8 0, i8* %22
%23 = load i8*, i8** %6
%24 = load i8*, i8** %4
%25 = call i32 @strcat(i8* %23, i8* %24)
%26 = load i8*, i8** %6
%27 = load i8*, i8** %5
%28 = call i32 @strcat(i8* %26, i8* %27)
%29 = load i8*, i8** %6
store i8* %29, i8** %3
br label %30
30: ; preds = %20, %17
%31 = load i8*, i8** %3
ret i8* %31
}

LLVM IR (-O2):
@stderr = global i32 0
@.str = [15 x i8] c"malloc failed\0A\00"
define i8* @appendString(i8* %0, i8* %1) {
%3 = tail call i32 @strlen(i8* %0)
%4 = tail call i32 @strlen(i8* %1)
%5 = add i32 %3, 1
%6 = add i32 %5, %4
%7 = tail call i8* @malloc(i32 %6)
%8 = icmp eq i8* %7, null
br i1 %8, label %9, label %12
9: ; preds = %2
%10 = load i32, i32* @stderr
%11 = tail call i32 @fprintf(i32 %10, i8* getelementptr inbounds ([15 x i8], [15 x i8]* @.str, i64 0, i64 0))
br label %15
12: ; preds = %2
store i8 0, i8* %7
%13 = tail call i32 @strcat(i8* %7, i8* %0)
%14 = tail call i32 @strcat(i8* %7, i8* %1)
br label %15
15: ; preds = %12, %9
ret i8* %7
}