#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*/ assert(char *);
scalar_t__ malloc(size_t);
int /*<<< orphan*/ strncpy(char *, char const *, size_t);
char *CopynString(const char *src, size_t len) {
  if (!src)
    return NULL;
  char *ret = (char *)malloc(len + 1);
  assert(ret);
  if (!ret)
    return NULL;
  strncpy(ret, src, len);
  ret[len] = 0;
  return ret;
}


x86 assembly (clang, -O0):
<CopynString>:
push   %rbp
mov    %rsp,%rbp
sub    $0x20,%rsp
mov    %rdi,-0x10(%rbp)
mov    %rsi,-0x18(%rbp)
cmpq   $0x0,-0x10(%rbp)
jne    1158 <CopynString+0x28>
movq   $0x0,-0x8(%rbp)
jmp    11af <CopynString+0x7f>
mov    -0x18(%rbp),%rdi
add    $0x1,%rdi
call   1050 <malloc@plt>
mov    %rax,-0x20(%rbp)
mov    -0x20(%rbp),%rdi
call   1040 <assert@plt>
cmpq   $0x0,-0x20(%rbp)
jne    118a <CopynString+0x5a>
movq   $0x0,-0x8(%rbp)
jmp    11af <CopynString+0x7f>
mov    -0x20(%rbp),%rdi
mov    -0x10(%rbp),%rsi
mov    -0x18(%rbp),%rdx
call   1030 <strncpy@plt>
mov    -0x20(%rbp),%rax
mov    -0x18(%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):
<CopynString>:
push   %r15
push   %r14
push   %rbx
test   %rdi,%rdi
je     116e <CopynString+0x3e>
mov    %rsi,%r14
mov    %rdi,%r15
lea    0x1(%rsi),%rdi
call   1050 <malloc@plt>
mov    %rax,%rbx
mov    %rax,%rdi
call   1040 <assert@plt>
test   %rbx,%rbx
je     116e <CopynString+0x3e>
mov    %rbx,%rdi
mov    %r15,%rsi
mov    %r14,%rdx
call   1030 <strncpy@plt>
movb   $0x0,(%rbx,%r14,1)
jmp    1170 <CopynString+0x40>
xor    %ebx,%ebx
mov    %rbx,%rax
pop    %rbx
pop    %r14
pop    %r15
ret

LLVM IR (-O0):
define i8* @CopynString(i8* %0, i64 %1) {
%3 = alloca i8*
%4 = alloca i8*
%5 = alloca i64
%6 = alloca i8*
store i8* %0, i8** %4
store i64 %1, i64* %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 %29
10: ; preds = %2
%11 = load i64, i64* %5
%12 = add i64 %11, 1
%13 = call i64 @malloc(i64 %12)
%14 = inttoptr i64 %13 to i8*
store i8* %14, i8** %6
%15 = load i8*, i8** %6
%16 = call i32 @assert(i8* %15)
%17 = load i8*, i8** %6
%18 = icmp ne i8* %17, null
br i1 %18, label %20, label %19
19: ; preds = %10
store i8* null, i8** %3
br label %29
20: ; preds = %10
%21 = load i8*, i8** %6
%22 = load i8*, i8** %4
%23 = load i64, i64* %5
%24 = call i32 @strncpy(i8* %21, i8* %22, i64 %23)
%25 = load i8*, i8** %6
%26 = load i64, i64* %5
%27 = getelementptr inbounds i8, i8* %25, i64 %26
store i8 0, i8* %27
%28 = load i8*, i8** %6
store i8* %28, i8** %3
br label %29
29: ; preds = %20, %19, %9
%30 = load i8*, i8** %3
ret i8* %30
}

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