#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 *, size_t);
size_t strlen(char const *);
size_t my_strcpy(char *buf, const char *src, size_t bufsize) {
  size_t len = strlen(src);
  size_t ret = len;
  if (bufsize == 0)
    return ret;
  if (len >= bufsize)
    len = bufsize - 1;
  (void)memcpy(buf, src, len);
  buf[len] = '\0';
  return ret;
}


x86 assembly (clang, -O0):
<my_strcpy>:
push   %rbp
mov    %rsp,%rbp
sub    $0x30,%rsp
mov    %rdi,-0x10(%rbp)
mov    %rsi,-0x18(%rbp)
mov    %rdx,-0x20(%rbp)
mov    -0x18(%rbp),%rdi
call   1030 <strlen@plt>
mov    %rax,-0x28(%rbp)
mov    -0x28(%rbp),%rax
mov    %rax,-0x30(%rbp)
cmpq   $0x0,-0x20(%rbp)
jne    1161 <my_strcpy+0x41>
mov    -0x30(%rbp),%rax
mov    %rax,-0x8(%rbp)
jmp    11a0 <my_strcpy+0x80>
mov    -0x28(%rbp),%rax
cmp    -0x20(%rbp),%rax
jb     117b <my_strcpy+0x5b>
mov    -0x20(%rbp),%rax
sub    $0x1,%rax
mov    %rax,-0x28(%rbp)
mov    -0x10(%rbp),%rdi
mov    -0x18(%rbp),%rsi
mov    -0x28(%rbp),%rdx
call   1040 <memcpy@plt>
mov    -0x10(%rbp),%rax
mov    -0x28(%rbp),%rcx
movb   $0x0,(%rax,%rcx,1)
mov    -0x30(%rbp),%rax
mov    %rax,-0x8(%rbp)
mov    -0x8(%rbp),%rax
add    $0x30,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<my_strcpy>:
push   %r15
push   %r14
push   %r13
push   %r12
push   %rbx
mov    %rdx,%r13
mov    %rsi,%r15
mov    %rdi,%r14
mov    %rsi,%rdi
call   1030 <strlen@plt>
mov    %rax,%r12
test   %r13,%r13
je     1160 <my_strcpy+0x40>
lea    -0x1(%r13),%rbx
cmp    %r13,%r12
cmovb  %r12,%rbx
mov    %r14,%rdi
mov    %r15,%rsi
mov    %rbx,%rdx
call   1040 <memcpy@plt>
movb   $0x0,(%r14,%rbx,1)
mov    %r12,%rax
pop    %rbx
pop    %r12
pop    %r13
pop    %r14
pop    %r15
ret

LLVM IR (-O0):
define i64 @my_strcpy(i8* %0, i8* %1, i64 %2) {
%4 = alloca i64
%5 = alloca i8*
%6 = alloca i8*
%7 = alloca i64
%8 = alloca i64
%9 = alloca i64
store i8* %0, i8** %5
store i8* %1, i8** %6
store i64 %2, i64* %7
%10 = load i8*, i8** %6
%11 = call i64 @strlen(i8* %10)
store i64 %11, i64* %8
%12 = load i64, i64* %8
store i64 %12, i64* %9
%13 = load i64, i64* %7
%14 = icmp eq i64 %13, 0
br i1 %14, label %15, label %17
15: ; preds = %3
%16 = load i64, i64* %9
store i64 %16, i64* %4
br label %33
17: ; preds = %3
%18 = load i64, i64* %8
%19 = load i64, i64* %7
%20 = icmp uge i64 %18, %19
br i1 %20, label %21, label %24
21: ; preds = %17
%22 = load i64, i64* %7
%23 = sub i64 %22, 1
store i64 %23, i64* %8
br label %24
24: ; preds = %21, %17
%25 = load i8*, i8** %5
%26 = load i8*, i8** %6
%27 = load i64, i64* %8
%28 = call i32 @memcpy(i8* %25, i8* %26, i64 %27)
%29 = load i8*, i8** %5
%30 = load i64, i64* %8
%31 = getelementptr inbounds i8, i8* %29, i64 %30
store i8 0, i8* %31
%32 = load i64, i64* %9
store i64 %32, i64* %4
br label %33
33: ; preds = %24, %15
%34 = load i64, i64* %4
ret i64 %34
}

LLVM IR (-O2):
define i64 @my_strcpy(i8* %0, i8* %1, i64 %2) {
%4 = tail call i64 @strlen(i8* dereferenceable(1) %1)
%5 = icmp eq i64 %2, 0
br i1 %5, label %12, label %6
6: ; preds = %3
%7 = icmp ult i64 %4, %2
%8 = add i64 %2, -1
%9 = select i1 %7, i64 %4, i64 %8
%10 = tail call i32 @memcpy(i8* %0, i8* %1, i64 %9)
%11 = getelementptr inbounds i8, i8* %0, i64 %9
store i8 0, i8* %11
br label %12
12: ; preds = %3, %6
ret i64 %4
}