#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*/ memcpy(char *, char const *, int);
char *rs_realloc(int /*<<< orphan*/, int);
int strlen(char const *);
char *rs_strdup(const char *str) {
  int n;
  char *p;
  if (!str)
    return NULL;
  n = strlen(str);
  p = rs_realloc(0, (n + 1));
  if (p)
    memcpy(p, str, n + 1);
  return p;
}


x86 assembly (clang, -O0):
<rs_strdup>:
push   %rbp
mov    %rsp,%rbp
sub    $0x20,%rsp
mov    %rdi,-0x10(%rbp)
cmpq   $0x0,-0x10(%rbp)
jne    1154 <rs_strdup+0x24>
movq   $0x0,-0x8(%rbp)
jmp    1197 <rs_strdup+0x67>
mov    -0x10(%rbp),%rdi
call   1030 <strlen@plt>
mov    %eax,-0x14(%rbp)
mov    -0x14(%rbp),%esi
add    $0x1,%esi
xor    %edi,%edi
call   1050 <rs_realloc@plt>
mov    %rax,-0x20(%rbp)
cmpq   $0x0,-0x20(%rbp)
je     118f <rs_strdup+0x5f>
mov    -0x20(%rbp),%rdi
mov    -0x10(%rbp),%rsi
mov    -0x14(%rbp),%edx
add    $0x1,%edx
call   1040 <memcpy@plt>
mov    -0x20(%rbp),%rax
mov    %rax,-0x8(%rbp)
mov    -0x8(%rbp),%rax
add    $0x20,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<rs_strdup>:
push   %rbp
push   %r15
push   %r14
push   %rbx
push   %rax
test   %rdi,%rdi
je     116f <rs_strdup+0x3f>
mov    %rdi,%rbx
call   1030 <strlen@plt>
mov    %eax,%ebp
add    $0x1,%ebp
xor    %r14d,%r14d
xor    %edi,%edi
mov    %ebp,%esi
call   1050 <rs_realloc@plt>
test   %rax,%rax
je     1172 <rs_strdup+0x42>
mov    %rax,%r15
mov    %rax,%rdi
mov    %rbx,%rsi
mov    %ebp,%edx
call   1040 <memcpy@plt>
mov    %r15,%r14
jmp    1172 <rs_strdup+0x42>
xor    %r14d,%r14d
mov    %r14,%rax
add    $0x8,%rsp
pop    %rbx
pop    %r14
pop    %r15
pop    %rbp
ret

LLVM IR (-O0):
define i8* @rs_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 %25
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* @rs_realloc(i32 0, i32 %13)
store i8* %14, i8** %5
%15 = load i8*, i8** %5
%16 = icmp ne i8* %15, null
br i1 %16, label %17, label %23
17: ; preds = %9
%18 = load i8*, i8** %5
%19 = load i8*, i8** %3
%20 = load i32, i32* %4
%21 = add nsw i32 %20, 1
%22 = call i32 @memcpy(i8* %18, i8* %19, i32 %21)
br label %23
23: ; preds = %17, %9
%24 = load i8*, i8** %5
store i8* %24, i8** %2
br label %25
25: ; preds = %23, %8
%26 = load i8*, i8** %2
ret i8* %26
}

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