#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 */
size_t strlen(char const *);
scalar_t__ strncmp(char const *, char const *, size_t const);
bool string_match_end(const char *str, const char *pat) {
  const size_t str_len = strlen(str);
  const size_t pat_len = strlen(pat);
  return (str_len > pat_len &&
          strncmp(&str[str_len - pat_len], pat, pat_len) == 0);
}


x86 assembly (clang, -O0):
<string_match_end>:
push   %rbp
mov    %rsp,%rbp
sub    $0x30,%rsp
mov    %rdi,-0x8(%rbp)
mov    %rsi,-0x10(%rbp)
mov    -0x8(%rbp),%rdi
call   1040 <strlen@plt>
mov    %rax,-0x18(%rbp)
mov    -0x10(%rbp),%rdi
call   1040 <strlen@plt>
mov    %rax,-0x20(%rbp)
mov    -0x18(%rbp),%rcx
xor    %eax,%eax
cmp    -0x20(%rbp),%rcx
mov    %al,-0x21(%rbp)
jbe    1183 <string_match_end+0x63>
mov    -0x8(%rbp),%rdi
mov    -0x18(%rbp),%rax
sub    -0x20(%rbp),%rax
add    %rax,%rdi
mov    -0x10(%rbp),%rsi
mov    -0x20(%rbp),%rdx
call   1030 <strncmp@plt>
cmp    $0x0,%rax
sete   %al
mov    %al,-0x21(%rbp)
mov    -0x21(%rbp),%al
and    $0x1,%al
movzbl %al,%eax
add    $0x30,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<string_match_end>:
push   %r15
push   %r14
push   %rbx
mov    %rsi,%r14
mov    %rdi,%r15
call   1040 <strlen@plt>
mov    %rax,%rbx
mov    %r14,%rdi
call   1040 <strlen@plt>
xor    %ecx,%ecx
sub    %rax,%rbx
jbe    115b <string_match_end+0x3b>
add    %rbx,%r15
mov    %r15,%rdi
mov    %r14,%rsi
mov    %rax,%rdx
call   1030 <strncmp@plt>
xor    %ecx,%ecx
test   %rax,%rax
sete   %cl
mov    %ecx,%eax
pop    %rbx
pop    %r14
pop    %r15
ret

LLVM IR (-O0):
define i32 @string_match_end(i8* %0, i8* %1) {
%3 = alloca i8*
%4 = alloca i8*
%5 = alloca i64
%6 = alloca i64
store i8* %0, i8** %3
store i8* %1, i8** %4
%7 = load i8*, i8** %3
%8 = call i64 @strlen(i8* %7)
store i64 %8, i64* %5
%9 = load i8*, i8** %4
%10 = call i64 @strlen(i8* %9)
store i64 %10, i64* %6
%11 = load i64, i64* %5
%12 = load i64, i64* %6
%13 = icmp ugt i64 %11, %12
br i1 %13, label %14, label %24
14: ; preds = %2
%15 = load i8*, i8** %3
%16 = load i64, i64* %5
%17 = load i64, i64* %6
%18 = sub i64 %16, %17
%19 = getelementptr inbounds i8, i8* %15, i64 %18
%20 = load i8*, i8** %4
%21 = load i64, i64* %6
%22 = call i64 @strncmp(i8* %19, i8* %20, i64 %21)
%23 = icmp eq i64 %22, 0
br label %24
24: ; preds = %14, %2
%25 = phi i1 [ false, %2 ], [ %23, %14 ]
%26 = zext i1 %25 to i32
ret i32 %26
}

LLVM IR (-O2):
define i32 @string_match_end(i8* %0, i8* %1) {
%3 = tail call i64 @strlen(i8* dereferenceable(1) %0)
%4 = tail call i64 @strlen(i8* dereferenceable(1) %1)
%5 = icmp ugt i64 %3, %4
br i1 %5, label %6, label %12
6: ; preds = %2
%7 = sub i64 %3, %4
%8 = getelementptr inbounds i8, i8* %0, i64 %7
%9 = tail call i64 @strncmp(i8* %8, i8* %1, i64 %4)
%10 = icmp eq i64 %9, 0
%11 = zext i1 %10 to i32
br label %12
12: ; preds = %6, %2
%13 = phi i32 [ 0, %2 ], [ %11, %6 ]
ret i32 %13
}