#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 strlen(char const *);
int starts_with(const char *haystack, const char *needle) {
  int len_needle, len_haystack, i;
  len_needle = strlen(needle);
  len_haystack = strlen(haystack);
  if (len_needle > len_haystack) {
    return 0;
  }
  for (i = 0; i < len_needle; i++) {
    if (haystack[i] != needle[i]) {
      return 0;
    }
  }
  return 1;
}


x86 assembly (clang, -O0):
<starts_with>:
push   %rbp
mov    %rsp,%rbp
sub    $0x30,%rsp
mov    %rdi,-0x10(%rbp)
mov    %rsi,-0x18(%rbp)
mov    -0x18(%rbp),%rdi
call   1030 <strlen@plt>
mov    %eax,-0x1c(%rbp)
mov    -0x10(%rbp),%rdi
call   1030 <strlen@plt>
mov    %eax,-0x20(%rbp)
mov    -0x1c(%rbp),%eax
cmp    -0x20(%rbp),%eax
jle    1150 <starts_with+0x40>
movl   $0x0,-0x4(%rbp)
jmp    11a9 <starts_with+0x99>
movl   $0x0,-0x24(%rbp)
mov    -0x24(%rbp),%eax
cmp    -0x1c(%rbp),%eax
jge    11a2 <starts_with+0x92>
mov    -0x10(%rbp),%rax
movslq -0x24(%rbp),%rcx
movsbl (%rax,%rcx,1),%eax
mov    -0x18(%rbp),%rcx
movslq -0x24(%rbp),%rdx
movsbl (%rcx,%rdx,1),%ecx
cmp    %ecx,%eax
je     118f <starts_with+0x7f>
movl   $0x0,-0x4(%rbp)
jmp    11a9 <starts_with+0x99>
jmp    1194 <starts_with+0x84>
mov    -0x24(%rbp),%eax
add    $0x1,%eax
mov    %eax,-0x24(%rbp)
jmp    1157 <starts_with+0x47>
movl   $0x1,-0x4(%rbp)
mov    -0x4(%rbp),%eax
add    $0x30,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<starts_with>:
push   %rbp
push   %r14
push   %rbx
mov    %rsi,%r14
mov    %rdi,%rbp
mov    %rsi,%rdi
call   1030 <strlen@plt>
mov    %eax,%ebx
mov    %rbp,%rdi
call   1030 <strlen@plt>
mov    %eax,%ecx
xor    %eax,%eax
cmp    %ecx,%ebx
jg     1168 <starts_with+0x58>
mov    $0x1,%eax
test   %ebx,%ebx
jle    1168 <starts_with+0x58>
mov    %ebx,%ecx
xor    %edx,%edx
cs nopw 0x0(%rax,%rax,1)
nopl   0x0(%rax,%rax,1)
movzbl 0x0(%rbp,%rdx,1),%ebx
cmp    (%r14,%rdx,1),%bl
jne    1166 <starts_with+0x56>
add    $0x1,%rdx
cmp    %rdx,%rcx
jne    1150 <starts_with+0x40>
jmp    1168 <starts_with+0x58>
xor    %eax,%eax
pop    %rbx
pop    %r14
pop    %rbp
ret

LLVM IR (-O0):
define i32 @starts_with(i8* %0, i8* %1) {
%3 = alloca i32
%4 = alloca i8*
%5 = alloca i8*
%6 = alloca i32
%7 = alloca i32
%8 = alloca i32
store i8* %0, i8** %4
store i8* %1, i8** %5
%9 = load i8*, i8** %5
%10 = call i32 @strlen(i8* %9)
store i32 %10, i32* %6
%11 = load i8*, i8** %4
%12 = call i32 @strlen(i8* %11)
store i32 %12, i32* %7
%13 = load i32, i32* %6
%14 = load i32, i32* %7
%15 = icmp sgt i32 %13, %14
br i1 %15, label %16, label %17
16: ; preds = %2
store i32 0, i32* %3
br label %42
17: ; preds = %2
store i32 0, i32* %8
br label %18
18: ; preds = %38, %17
%19 = load i32, i32* %8
%20 = load i32, i32* %6
%21 = icmp slt i32 %19, %20
br i1 %21, label %22, label %41
22: ; preds = %18
%23 = load i8*, i8** %4
%24 = load i32, i32* %8
%25 = sext i32 %24 to i64
%26 = getelementptr inbounds i8, i8* %23, i64 %25
%27 = load i8, i8* %26
%28 = sext i8 %27 to i32
%29 = load i8*, i8** %5
%30 = load i32, i32* %8
%31 = sext i32 %30 to i64
%32 = getelementptr inbounds i8, i8* %29, i64 %31
%33 = load i8, i8* %32
%34 = sext i8 %33 to i32
%35 = icmp ne i32 %28, %34
br i1 %35, label %36, label %37
36: ; preds = %22
store i32 0, i32* %3
br label %42
37: ; preds = %22
br label %38
38: ; preds = %37
%39 = load i32, i32* %8
%40 = add nsw i32 %39, 1
store i32 %40, i32* %8
br label %18
41: ; preds = %18
store i32 1, i32* %3
br label %42
42: ; preds = %41, %36, %16
%43 = load i32, i32* %3
ret i32 %43
}

LLVM IR (-O2):
define i32 @starts_with(i8* %0, i8* %1) {
%3 = tail call i32 @strlen(i8* %1)
%4 = tail call i32 @strlen(i8* %0)
%5 = icmp sgt i32 %3, %4
br i1 %5, label %20, label %6
6: ; preds = %2
%7 = icmp sgt i32 %3, 0
br i1 %7, label %8, label %20
8: ; preds = %6
%9 = zext i32 %3 to i64
br label %12
10: ; preds = %12
%11 = icmp eq i64 %19, %9
br i1 %11, label %20, label %12
12: ; preds = %8, %10
%13 = phi i64 [ 0, %8 ], [ %19, %10 ]
%14 = getelementptr inbounds i8, i8* %0, i64 %13
%15 = load i8, i8* %14
%16 = getelementptr inbounds i8, i8* %1, i64 %13
%17 = load i8, i8* %16
%18 = icmp eq i8 %15, %17
%19 = add nuw nsw i64 %13, 1
br i1 %18, label %10, label %20
20: ; preds = %12, %10, %6, %2
%21 = phi i32 [ 0, %2 ], [ 1, %6 ], [ 0, %12 ], [ 1, %10 ]
ret i32 %21
}