#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__ malloc(int);
int /*<<< orphan*/ memcpy(char *, char const *, int);
int strlen(char const *);
char *_strndup(const char *str, int nlen) {
  char *str2;
  if (nlen == -1) {
    nlen = strlen(str);
  }
  str2 = (char *)malloc(nlen + 1);
  if (str2) {
    memcpy(str2, str, nlen);
    str2[nlen] = '\0';
  }
  return str2;
}


x86 assembly (clang, -O0):
<_strndup>:
push   %rbp
mov    %rsp,%rbp
sub    $0x20,%rsp
mov    %rdi,-0x8(%rbp)
mov    %esi,-0xc(%rbp)
cmpl   $0xffffffff,-0xc(%rbp)
jne    1155 <_strndup+0x25>
mov    -0x8(%rbp),%rdi
call   1030 <strlen@plt>
mov    %eax,-0xc(%rbp)
mov    -0xc(%rbp),%edi
add    $0x1,%edi
call   1050 <malloc@plt>
mov    %rax,-0x18(%rbp)
cmpq   $0x0,-0x18(%rbp)
je     118b <_strndup+0x5b>
mov    -0x18(%rbp),%rdi
mov    -0x8(%rbp),%rsi
mov    -0xc(%rbp),%edx
call   1040 <memcpy@plt>
mov    -0x18(%rbp),%rax
movslq -0xc(%rbp),%rcx
movb   $0x0,(%rax,%rcx,1)
mov    -0x18(%rbp),%rax
add    $0x20,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<_strndup>:
push   %r15
push   %r14
push   %rbx
mov    %esi,%r15d
mov    %rdi,%r14
cmp    $0xffffffff,%esi
jne    114b <_strndup+0x1b>
mov    %r14,%rdi
call   1030 <strlen@plt>
mov    %eax,%r15d
lea    0x1(%r15),%edi
call   1050 <malloc@plt>
mov    %rax,%rbx
test   %rax,%rax
je     1171 <_strndup+0x41>
mov    %rbx,%rdi
mov    %r14,%rsi
mov    %r15d,%edx
call   1040 <memcpy@plt>
movslq %r15d,%rax
movb   $0x0,(%rbx,%rax,1)
mov    %rbx,%rax
pop    %rbx
pop    %r14
pop    %r15
ret

LLVM IR (-O0):
define i8* @_strndup(i8* %0, i32 %1) {
%3 = alloca i8*
%4 = alloca i32
%5 = alloca i8*
store i8* %0, i8** %3
store i32 %1, i32* %4
%6 = load i32, i32* %4
%7 = icmp eq i32 %6, -1
br i1 %7, label %8, label %11
8: ; preds = %2
%9 = load i8*, i8** %3
%10 = call i32 @strlen(i8* %9)
store i32 %10, i32* %4
br label %11
11: ; preds = %8, %2
%12 = load i32, i32* %4
%13 = add nsw i32 %12, 1
%14 = call i64 @malloc(i32 %13)
%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 %18, label %27
18: ; preds = %11
%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
br label %27
27: ; preds = %18, %11
%28 = load i8*, i8** %5
ret i8* %28
}

LLVM IR (-O2):
define i8* @_strndup(i8* %0, i32 %1) {
%3 = icmp eq i32 %1, -1
br i1 %3, label %4, label %6
4: ; preds = %2
%5 = tail call i32 @strlen(i8* %0)
br label %6
6: ; preds = %4, %2
%7 = phi i32 [ %5, %4 ], [ %1, %2 ]
%8 = add nsw i32 %7, 1
%9 = tail call i64 @malloc(i32 %8)
%10 = inttoptr i64 %9 to i8*
%11 = icmp eq i64 %9, 0
br i1 %11, label %16, label %12
12: ; preds = %6
%13 = tail call i32 @memcpy(i8* %10, i8* %0, i32 %7)
%14 = sext i32 %7 to i64
%15 = getelementptr inbounds i8, i8* %10, i64 %14
store i8 0, i8* %15
br label %16
16: ; preds = %12, %6
ret i8* %10
}