#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(size_t);
char *memcpy(char *, char const *, size_t);
int strlen(char const *);
char *COSStyleStrDup(const char *s) {
  if (!s)
    return NULL;
  size_t len = (strlen(s) + 1);
  char *p = malloc(len * sizeof(char));
  if (p)
    return memcpy(p, s, len);
  else
    return NULL;
}


x86 assembly (clang, -O0):
<COSStyleStrDup>:
push   %rbp
mov    %rsp,%rbp
sub    $0x20,%rsp
mov    %rdi,-0x10(%rbp)
cmpq   $0x0,-0x10(%rbp)
jne    1154 <COSStyleStrDup+0x24>
movq   $0x0,-0x8(%rbp)
jmp    11a4 <COSStyleStrDup+0x74>
mov    -0x10(%rbp),%rdi
call   1030 <strlen@plt>
add    $0x1,%eax
cltq
mov    %rax,-0x18(%rbp)
mov    -0x18(%rbp),%rdi
shl    $0x0,%rdi
call   1050 <malloc@plt>
mov    %rax,-0x20(%rbp)
cmpq   $0x0,-0x20(%rbp)
je     119c <COSStyleStrDup+0x6c>
mov    -0x20(%rbp),%rdi
mov    -0x10(%rbp),%rsi
mov    -0x18(%rbp),%rdx
call   1040 <memcpy@plt>
mov    %rax,-0x8(%rbp)
jmp    11a4 <COSStyleStrDup+0x74>
movq   $0x0,-0x8(%rbp)
mov    -0x8(%rbp),%rax
add    $0x20,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<COSStyleStrDup>:
push   %r15
push   %r14
push   %rbx
test   %rdi,%rdi
je     1168 <COSStyleStrDup+0x38>
mov    %rdi,%r14
call   1030 <strlen@plt>
add    $0x1,%eax
movslq %eax,%r15
mov    %r15,%rdi
call   1050 <malloc@plt>
test   %rax,%rax
je     1168 <COSStyleStrDup+0x38>
mov    %rax,%rbx
mov    %rax,%rdi
mov    %r14,%rsi
mov    %r15,%rdx
call   1040 <memcpy@plt>
jmp    116a <COSStyleStrDup+0x3a>
xor    %ebx,%ebx
mov    %rbx,%rax
pop    %rbx
pop    %r14
pop    %r15
ret

LLVM IR (-O0):
define i8* @COSStyleStrDup(i8* %0) {
%2 = alloca i8*
%3 = alloca i8*
%4 = alloca i64
%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)
%12 = add nsw i32 %11, 1
%13 = sext i32 %12 to i64
store i64 %13, i64* %4
%14 = load i64, i64* %4
%15 = mul i64 %14, 1
%16 = call i8* @malloc(i64 %15)
store i8* %16, i8** %5
%17 = load i8*, i8** %5
%18 = icmp ne i8* %17, null
br i1 %18, label %19, label %24
19: ; preds = %9
%20 = load i8*, i8** %5
%21 = load i8*, i8** %3
%22 = load i64, i64* %4
%23 = call i8* @memcpy(i8* %20, i8* %21, i64 %22)
store i8* %23, i8** %2
br label %25
24: ; preds = %9
store i8* null, i8** %2
br label %25
25: ; preds = %24, %19, %8
%26 = load i8*, i8** %2
ret i8* %26
}

LLVM IR (-O2):
define noalias i8* @COSStyleStrDup(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 = sext i32 %5 to i64
%7 = tail call i8* @malloc(i64 %6)
%8 = icmp eq i8* %7, null
br i1 %8, label %10, label %9
9: ; preds = %3
tail call void @llvm.memcpy.p0i8.p0i8.i64(i8* align 1 %7, i8* align 1 %0, i64 %6, i1 false)
br label %10
10: ; preds = %9, %3, %1
%11 = phi i8* [ null, %1 ], [ %7, %9 ], [ null, %3 ]
ret i8* %11
}