#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 */
typedef scalar_t__ memcmp;

/* Variables and functions */
size_t strcnlen(char const *, int, size_t);
char *(strcnstarts)(const char *string, const char *desired, int stop,
                    size_t maxlen) {
  size_t n = strcnlen(string, stop, maxlen);
  size_t m = strcnlen(desired, stop, maxlen);
  if (n < m)
    return NULL;
  return (memcmp)(string, desired, m) ? NULL : string;
}


x86 assembly (clang, -O0):
<strcnstarts>:
push   %rbp
mov    %rsp,%rbp
sub    $0x40,%rsp
mov    %rdi,-0x10(%rbp)
mov    %rsi,-0x18(%rbp)
mov    %edx,-0x1c(%rbp)
mov    %rcx,-0x28(%rbp)
mov    -0x10(%rbp),%rdi
mov    -0x1c(%rbp),%esi
mov    -0x28(%rbp),%rdx
call   1030 <strcnlen@plt>
mov    %rax,-0x30(%rbp)
mov    -0x18(%rbp),%rdi
mov    -0x1c(%rbp),%esi
mov    -0x28(%rbp),%rdx
call   1030 <strcnlen@plt>
mov    %rax,-0x38(%rbp)
mov    -0x30(%rbp),%rax
cmp    -0x38(%rbp),%rax
jae    116a <strcnstarts+0x5a>
movq   $0x0,-0x8(%rbp)
jmp    1190 <strcnstarts+0x80>
cmpq   $0x0,-0x38(%rbp)
je     1180 <strcnstarts+0x70>
xor    %eax,%eax
mov    %rax,-0x40(%rbp)
jmp    1188 <strcnstarts+0x78>
mov    -0x10(%rbp),%rax
mov    %rax,-0x40(%rbp)
mov    -0x40(%rbp),%rax
mov    %rax,-0x8(%rbp)
mov    -0x8(%rbp),%rax
add    $0x40,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<strcnstarts>:
push   %rbp
push   %r15
push   %r14
push   %r12
push   %rbx
mov    %rcx,%r15
mov    %edx,%ebp
mov    %rsi,%r14
mov    %rdi,%rbx
mov    %edx,%esi
mov    %rcx,%rdx
call   1030 <strcnlen@plt>
mov    %rax,%r12
mov    %r14,%rdi
mov    %ebp,%esi
mov    %r15,%rdx
call   1030 <strcnlen@plt>
xor    %ecx,%ecx
test   %rax,%rax
cmovne %rcx,%rbx
cmp    %rax,%r12
cmovb  %rcx,%rbx
mov    %rbx,%rax
pop    %rbx
pop    %r12
pop    %r14
pop    %r15
pop    %rbp
ret

LLVM IR (-O0):
define i8* @strcnstarts(i8* %0, i8* %1, i32 %2, i64 %3) {
%5 = alloca i8*
%6 = alloca i8*
%7 = alloca i8*
%8 = alloca i32
%9 = alloca i64
%10 = alloca i64
%11 = alloca i64
store i8* %0, i8** %6
store i8* %1, i8** %7
store i32 %2, i32* %8
store i64 %3, i64* %9
%12 = load i8*, i8** %6
%13 = load i32, i32* %8
%14 = load i64, i64* %9
%15 = call i64 @strcnlen(i8* %12, i32 %13, i64 %14)
store i64 %15, i64* %10
%16 = load i8*, i8** %7
%17 = load i32, i32* %8
%18 = load i64, i64* %9
%19 = call i64 @strcnlen(i8* %16, i32 %17, i64 %18)
store i64 %19, i64* %11
%20 = load i64, i64* %10
%21 = load i64, i64* %11
%22 = icmp ult i64 %20, %21
br i1 %22, label %23, label %24
23: ; preds = %4
store i8* null, i8** %5
br label %34
24: ; preds = %4
%25 = load i8*, i8** %6
%26 = load i8*, i8** %7
%27 = load i64, i64* %11
%28 = icmp ne i64 %27, 0
br i1 %28, label %29, label %30
29: ; preds = %24
br label %32
30: ; preds = %24
%31 = load i8*, i8** %6
br label %32
32: ; preds = %30, %29
%33 = phi i8* [ null, %29 ], [ %31, %30 ]
store i8* %33, i8** %5
br label %34
34: ; preds = %32, %23
%35 = load i8*, i8** %5
ret i8* %35
}

LLVM IR (-O2):
define i8* @strcnstarts(i8* %0, i8* %1, i32 %2, i64 %3) {
%5 = tail call i64 @strcnlen(i8* %0, i32 %2, i64 %3)
%6 = tail call i64 @strcnlen(i8* %1, i32 %2, i64 %3)
%7 = icmp ult i64 %5, %6
%8 = icmp eq i64 %6, 0
%9 = select i1 %8, i8* %0, i8* null
%10 = select i1 %7, i8* null, i8* %9
ret i8* %10
}