#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 /*<<< orphan*/ fgets(char *, int, int /*<<< orphan*/);
int /*<<< orphan*/ printf(char *, ...);
int /*<<< orphan*/ reverse(char *);
int /*<<< orphan*/ stdin;
int strlen(char *);
int main() {
  char input[1024];
  printf("Please enter the string: ");
  fgets(input, 1024, stdin);
  input[strlen(input) - 1] = '\0';
  reverse(input);
  printf("The reversed string is: %s\n", input);
  return 0;
}


x86 assembly (clang, -O0):
<main>:
push   %rbp
mov    %rsp,%rbp
sub    $0x410,%rsp
movl   $0x0,-0x4(%rbp)
lea    0xea7(%rip),%rdi
mov    $0x0,%al
call   1050 <printf@plt>
lea    -0x410(%rbp),%rdi
mov    0x2e7a(%rip),%rax
mov    (%rax),%edx
mov    $0x400,%esi
call   1060 <fgets@plt>
lea    -0x410(%rbp),%rdi
call   1040 <strlen@plt>
sub    $0x1,%eax
cltq
movb   $0x0,-0x410(%rbp,%rax,1)
lea    -0x410(%rbp),%rdi
call   1030 <reverse@plt>
lea    -0x410(%rbp),%rsi
lea    0xe6d(%rip),%rdi
mov    $0x0,%al
call   1050 <printf@plt>
xor    %eax,%eax
add    $0x410,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<main>:
push   %rbx
sub    $0x400,%rsp
lea    0xeb1(%rip),%rdi
xor    %eax,%eax
call   1050 <printf@plt>
mov    0x2e8b(%rip),%rax
mov    (%rax),%edx
mov    %rsp,%rbx
mov    %rbx,%rdi
mov    $0x400,%esi
call   1060 <fgets@plt>
mov    %rbx,%rdi
call   1040 <strlen@plt>
cltq
movb   $0x0,-0x1(%rax,%rbx,1)
mov    %rbx,%rdi
call   1030 <reverse@plt>
lea    0xe8d(%rip),%rdi
mov    %rbx,%rsi
xor    %eax,%eax
call   1050 <printf@plt>
xor    %eax,%eax
add    $0x400,%rsp
pop    %rbx
ret

LLVM IR (-O0):
@.str = [26 x i8] c"Please enter the string: \00"
@stdin = global i32 0
@.str.1 = [28 x i8] c"The reversed string is: %s\0A\00"
define i32 @main() {
%1 = alloca i32
%2 = alloca [1024 x i8]
store i32 0, i32* %1
%3 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([26 x i8], [26 x i8]* @.str, i64 0, i64 0))
%4 = getelementptr inbounds [1024 x i8], [1024 x i8]* %2, i64 0, i64 0
%5 = load i32, i32* @stdin
%6 = call i32 @fgets(i8* %4, i32 1024, i32 %5)
%7 = getelementptr inbounds [1024 x i8], [1024 x i8]* %2, i64 0, i64 0
%8 = call i32 @strlen(i8* %7)
%9 = sub nsw i32 %8, 1
%10 = sext i32 %9 to i64
%11 = getelementptr inbounds [1024 x i8], [1024 x i8]* %2, i64 0, i64 %10
store i8 0, i8* %11
%12 = getelementptr inbounds [1024 x i8], [1024 x i8]* %2, i64 0, i64 0
%13 = call i32 @reverse(i8* %12)
%14 = getelementptr inbounds [1024 x i8], [1024 x i8]* %2, i64 0, i64 0
%15 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([28 x i8], [28 x i8]* @.str.1, i64 0, i64 0), i8* %14)
ret i32 0
}

LLVM IR (-O2):
@.str = [26 x i8] c"Please enter the string: \00"
@stdin = global i32 0
@.str.1 = [28 x i8] c"The reversed string is: %s\0A\00"
define i32 @main() {
%1 = alloca [1024 x i8]
%2 = getelementptr inbounds [1024 x i8], [1024 x i8]* %1, i64 0, i64 0
%3 = tail call i32 (i8*, ...) @printf(i8* dereferenceable(1) getelementptr inbounds ([26 x i8], [26 x i8]* @.str, i64 0, i64 0))
%4 = load i32, i32* @stdin
%5 = call i32 @fgets(i8* %2, i32 1024, i32 %4)
%6 = call i32 @strlen(i8* %2)
%7 = add nsw i32 %6, -1
%8 = sext i32 %7 to i64
%9 = getelementptr inbounds [1024 x i8], [1024 x i8]* %1, i64 0, i64 %8
store i8 0, i8* %9
%10 = call i32 @reverse(i8* %2)
%11 = call i32 (i8*, ...) @printf(i8* dereferenceable(1) getelementptr inbounds ([28 x i8], [28 x i8]* @.str.1, i64 0, i64 0), i8* %2)
ret i32 0
}