#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 *malloc(int);
int /*<<< orphan*/ memcpy(char *, char const *, int);
int strlen(char const *);
char *my_strdup(const char *s) {
  if (!s)
    return NULL;
  int l = strlen(s);
  char *d = malloc(l + 1);
  if (!d)
    return NULL;
  memcpy(d, s, l);
  d[l] = '\0';
  return d;
}


x86 assembly (clang, -O0):
<my_strdup>:
push   %rbp
mov    %rsp,%rbp
sub    $0x20,%rsp
mov    %rdi,-0x10(%rbp)
cmpq   $0x0,-0x10(%rbp)
jne    1154 <my_strdup+0x24>
movq   $0x0,-0x8(%rbp)
jmp    11ab <my_strdup+0x7b>
mov    -0x10(%rbp),%rdi
call   1030 <strlen@plt>
mov    %eax,-0x14(%rbp)
mov    -0x14(%rbp),%edi
add    $0x1,%edi
call   1050 <malloc@plt>
mov    %rax,-0x20(%rbp)
cmpq   $0x0,-0x20(%rbp)
jne    1187 <my_strdup+0x57>
movq   $0x0,-0x8(%rbp)
jmp    11ab <my_strdup+0x7b>
mov    -0x20(%rbp),%rdi
mov    -0x10(%rbp),%rsi
mov    -0x14(%rbp),%edx
call   1040 <memcpy@plt>
mov    -0x20(%rbp),%rax
movslq -0x14(%rbp),%rcx
movb   $0x0,(%rax,%rcx,1)
mov    -0x20(%rbp),%rax
mov    %rax,-0x8(%rbp)
mov    -0x8(%rbp),%rax
add    $0x20,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<my_strdup>:
push   %r15
push   %r14
push   %rbx
test   %rdi,%rdi
je     116d <my_strdup+0x3d>
mov    %rdi,%r14
call   1030 <strlen@plt>
mov    %eax,%r15d
lea    0x1(%r15),%edi
call   1050 <malloc@plt>
test   %rax,%rax
je     116d <my_strdup+0x3d>
mov    %rax,%rbx
mov    %rax,%rdi
mov    %r14,%rsi
mov    %r15d,%edx
call   1040 <memcpy@plt>
movslq %r15d,%rax
movb   $0x0,(%rbx,%rax,1)
jmp    116f <my_strdup+0x3f>
xor    %ebx,%ebx
mov    %rbx,%rax
pop    %rbx
pop    %r14
pop    %r15
ret

LLVM IR (-O0):
define i8* @my_strdup(i8* %0) {
%2 = alloca i8*
%3 = alloca i8*
%4 = alloca i32
%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 %28
9: ; preds = %1
%10 = load i8*, i8** %3
%11 = call i32 @strlen(i8* %10)
store i32 %11, i32* %4
%12 = load i32, i32* %4
%13 = add nsw i32 %12, 1
%14 = call i8* @malloc(i32 %13)
store i8* %14, i8** %5
%15 = load i8*, i8** %5
%16 = icmp ne i8* %15, null
br i1 %16, label %18, label %17
17: ; preds = %9
store i8* null, i8** %2
br label %28
18: ; preds = %9
%19 = load i8*, i8** %5
%20 = load i8*, i8** %3
%21 = load i32, i32* %4
%22 = call i32 @memcpy(i8* %19, i8* %20, i32 %21)
%23 = load i8*, i8** %5
%24 = load i32, i32* %4
%25 = sext i32 %24 to i64
%26 = getelementptr inbounds i8, i8* %23, i64 %25
store i8 0, i8* %26
%27 = load i8*, i8** %5
store i8* %27, i8** %2
br label %28
28: ; preds = %18, %17, %8
%29 = load i8*, i8** %2
ret i8* %29
}

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