#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(size_t);
int /*<<< orphan*/ memcpy(char *, char const *, size_t);
int strlen(char const *);
char *xstrdup(const char *src) {
  if (src) {
    size_t src_size = strlen(src) + 1;
    char *new = (char *)malloc(src_size);
    if (new) {
      memcpy(new, src, src_size);
      return new;
    }
  }
  return NULL;
}


x86 assembly (clang, -O0):
<xstrdup>:
push   %rbp
mov    %rsp,%rbp
sub    $0x20,%rsp
mov    %rdi,-0x10(%rbp)
cmpq   $0x0,-0x10(%rbp)
je     1194 <xstrdup+0x64>
mov    -0x10(%rbp),%rdi
call   1030 <strlen@plt>
add    $0x1,%eax
cltq
mov    %rax,-0x18(%rbp)
mov    -0x18(%rbp),%rdi
call   1050 <malloc@plt>
mov    %rax,-0x20(%rbp)
cmpq   $0x0,-0x20(%rbp)
je     118f <xstrdup+0x5f>
mov    -0x20(%rbp),%rdi
mov    -0x10(%rbp),%rsi
mov    -0x18(%rbp),%rdx
call   1040 <memcpy@plt>
mov    -0x20(%rbp),%rax
mov    %rax,-0x8(%rbp)
jmp    119c <xstrdup+0x6c>
jmp    1194 <xstrdup+0x64>
movq   $0x0,-0x8(%rbp)
mov    -0x8(%rbp),%rax
add    $0x20,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<xstrdup>:
push   %r15
push   %r14
push   %rbx
test   %rdi,%rdi
je     1168 <xstrdup+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 <xstrdup+0x38>
mov    %rax,%rbx
mov    %rax,%rdi
mov    %r14,%rsi
mov    %r15,%rdx
call   1040 <memcpy@plt>
jmp    116a <xstrdup+0x3a>
xor    %ebx,%ebx
mov    %rbx,%rax
pop    %rbx
pop    %r14
pop    %r15
ret

LLVM IR (-O0):
define i8* @xstrdup(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 %8, label %25
8: ; preds = %1
%9 = load i8*, i8** %3
%10 = call i32 @strlen(i8* %9)
%11 = add nsw i32 %10, 1
%12 = sext i32 %11 to i64
store i64 %12, i64* %4
%13 = load i64, i64* %4
%14 = call i64 @malloc(i64 %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 %24
18: ; preds = %8
%19 = load i8*, i8** %5
%20 = load i8*, i8** %3
%21 = load i64, i64* %4
%22 = call i32 @memcpy(i8* %19, i8* %20, i64 %21)
%23 = load i8*, i8** %5
store i8* %23, i8** %2
br label %26
24: ; preds = %8
br label %25
25: ; preds = %24, %1
store i8* null, i8** %2
br label %26
26: ; preds = %25, %18
%27 = load i8*, i8** %2
ret i8* %27
}

LLVM IR (-O2):
define i8* @xstrdup(i8* %0) {
%2 = icmp eq i8* %0, null
br i1 %2, label %12, 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 i64 @malloc(i64 %6)
%8 = inttoptr i64 %7 to i8*
%9 = icmp eq i64 %7, 0
br i1 %9, label %12, label %10
10: ; preds = %3
%11 = tail call i32 @memcpy(i8* %8, i8* %0, i64 %6)
br label %12
12: ; preds = %3, %1, %10
%13 = phi i8* [ %8, %10 ], [ null, %1 ], [ null, %3 ]
ret i8* %13
}