#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__ calloc(size_t, int);
scalar_t__ memcpy(char *, char const *, size_t);
size_t strlen(char const *);
char *mystrdup(const char *str) {
  if (!str)
    return NULL;
  size_t len = strlen(str);
  char *temp = (char *)calloc(len + 1, sizeof(char));
  if (!temp) {
    return NULL;
  }
  return (char *)memcpy(temp, str, len);
}


x86 assembly (clang, -O0):
<mystrdup>:
push   %rbp
mov    %rsp,%rbp
sub    $0x20,%rsp
mov    %rdi,-0x10(%rbp)
cmpq   $0x0,-0x10(%rbp)
jne    1154 <mystrdup+0x24>
movq   $0x0,-0x8(%rbp)
jmp    11a4 <mystrdup+0x74>
mov    -0x10(%rbp),%rdi
call   1030 <strlen@plt>
mov    %rax,-0x18(%rbp)
mov    -0x18(%rbp),%rdi
add    $0x1,%rdi
mov    $0x1,%esi
call   1040 <calloc@plt>
mov    %rax,-0x20(%rbp)
cmpq   $0x0,-0x20(%rbp)
jne    118f <mystrdup+0x5f>
movq   $0x0,-0x8(%rbp)
jmp    11a4 <mystrdup+0x74>
mov    -0x20(%rbp),%rdi
mov    -0x10(%rbp),%rsi
mov    -0x18(%rbp),%rdx
call   1050 <memcpy@plt>
mov    %rax,-0x8(%rbp)
mov    -0x8(%rbp),%rax
add    $0x20,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<mystrdup>:
push   %r14
push   %rbx
push   %rax
test   %rdi,%rdi
je     1167 <mystrdup+0x37>
mov    %rdi,%rbx
call   1030 <strlen@plt>
mov    %rax,%r14
lea    0x1(%rax),%rdi
mov    $0x1,%esi
call   1040 <calloc@plt>
test   %rax,%rax
je     1167 <mystrdup+0x37>
mov    %rax,%rdi
mov    %rbx,%rsi
mov    %r14,%rdx
call   1050 <memcpy@plt>
jmp    1169 <mystrdup+0x39>
xor    %eax,%eax
add    $0x8,%rsp
pop    %rbx
pop    %r14
ret

LLVM IR (-O0):
define i8* @mystrdup(i8* %0) {
%2 = alloca i8*
%3 = alloca i8*
%4 = alloca i64
%5 = alloca i8*
store i8* %0, i8** %3
%6 = load i8*, i8** %3
%7 = icmp ne i8* %6, null
br i1 %7, label %9, label %8
8: ; preds = %1
store i8* null, i8** %2
br label %25
9: ; preds = %1
%10 = load i8*, i8** %3
%11 = call i64 @strlen(i8* %10)
store i64 %11, i64* %4
%12 = load i64, i64* %4
%13 = add i64 %12, 1
%14 = call i64 @calloc(i64 %13, i32 1)
%15 = inttoptr i64 %14 to i8*
store i8* %15, i8** %5
%16 = load i8*, i8** %5
%17 = icmp ne i8* %16, null
br i1 %17, label %19, label %18
18: ; preds = %9
store i8* null, i8** %2
br label %25
19: ; preds = %9
%20 = load i8*, i8** %5
%21 = load i8*, i8** %3
%22 = load i64, i64* %4
%23 = call i64 @memcpy(i8* %20, i8* %21, i64 %22)
%24 = inttoptr i64 %23 to i8*
store i8* %24, i8** %2
br label %25
25: ; preds = %19, %18, %8
%26 = load i8*, i8** %2
ret i8* %26
}

LLVM IR (-O2):
define i8* @mystrdup(i8* %0) {
%2 = icmp eq i8* %0, null
br i1 %2, label %12, label %3
3: ; preds = %1
%4 = tail call i64 @strlen(i8* %0)
%5 = add i64 %4, 1
%6 = tail call i64 @calloc(i64 %5, i32 1)
%7 = icmp eq i64 %6, 0
br i1 %7, label %12, label %8
8: ; preds = %3
%9 = inttoptr i64 %6 to i8*
%10 = tail call i64 @memcpy(i8* %9, i8* %0, i64 %4)
%11 = inttoptr i64 %10 to i8*
br label %12
12: ; preds = %8, %3, %1
%13 = phi i8* [ null, %1 ], [ %11, %8 ], [ null, %3 ]
ret i8* %13
}