#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(unsigned int);
int /*<<< orphan*/ strncpy(char *, char const *, unsigned int);
char *s_ndup(const char *s, unsigned int len) {
  char *rs;
  if (!s)
    return NULL;
  rs = malloc(len + 1);
  if (!rs)
    return NULL;
  strncpy(rs, s, len);
  rs[len] = '\0';
  return rs;
}


x86 assembly (clang, -O0):
<s_ndup>:
push   %rbp
mov    %rsp,%rbp
sub    $0x20,%rsp
mov    %rdi,-0x10(%rbp)
mov    %esi,-0x14(%rbp)
cmpq   $0x0,-0x10(%rbp)
jne    1147 <s_ndup+0x27>
movq   $0x0,-0x8(%rbp)
jmp    1191 <s_ndup+0x71>
mov    -0x14(%rbp),%edi
add    $0x1,%edi
call   1040 <malloc@plt>
mov    %rax,-0x20(%rbp)
cmpq   $0x0,-0x20(%rbp)
jne    116e <s_ndup+0x4e>
movq   $0x0,-0x8(%rbp)
jmp    1191 <s_ndup+0x71>
mov    -0x20(%rbp),%rdi
mov    -0x10(%rbp),%rsi
mov    -0x14(%rbp),%edx
call   1030 <strncpy@plt>
mov    -0x20(%rbp),%rax
mov    -0x14(%rbp),%ecx
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):
<s_ndup>:
push   %r15
push   %r14
push   %rbx
test   %rdi,%rdi
je     1158 <s_ndup+0x38>
mov    %esi,%r14d
mov    %rdi,%r15
lea    0x1(%r14),%edi
call   1040 <malloc@plt>
test   %rax,%rax
je     1158 <s_ndup+0x38>
mov    %rax,%rbx
mov    %rax,%rdi
mov    %r15,%rsi
mov    %r14d,%edx
call   1030 <strncpy@plt>
mov    %r14d,%eax
movb   $0x0,(%rbx,%rax,1)
jmp    115a <s_ndup+0x3a>
xor    %ebx,%ebx
mov    %rbx,%rax
pop    %rbx
pop    %r14
pop    %r15
ret

LLVM IR (-O0):
define i8* @s_ndup(i8* %0, i32 %1) {
%3 = alloca i8*
%4 = alloca i8*
%5 = alloca i32
%6 = alloca i8*
store i8* %0, i8** %4
store i32 %1, i32* %5
%7 = load i8*, i8** %4
%8 = icmp ne i8* %7, null
br i1 %8, label %10, label %9
9: ; preds = %2
store i8* null, i8** %3
br label %27
10: ; preds = %2
%11 = load i32, i32* %5
%12 = add i32 %11, 1
%13 = call i8* @malloc(i32 %12)
store i8* %13, i8** %6
%14 = load i8*, i8** %6
%15 = icmp ne i8* %14, null
br i1 %15, label %17, label %16
16: ; preds = %10
store i8* null, i8** %3
br label %27
17: ; preds = %10
%18 = load i8*, i8** %6
%19 = load i8*, i8** %4
%20 = load i32, i32* %5
%21 = call i32 @strncpy(i8* %18, i8* %19, i32 %20)
%22 = load i8*, i8** %6
%23 = load i32, i32* %5
%24 = zext i32 %23 to i64
%25 = getelementptr inbounds i8, i8* %22, i64 %24
store i8 0, i8* %25
%26 = load i8*, i8** %6
store i8* %26, i8** %3
br label %27
27: ; preds = %17, %16, %9
%28 = load i8*, i8** %3
ret i8* %28
}

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