#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*/ printf(char *, ...);
int /*<<< orphan*/ scanf(char *, char *);
int strlen(char *);
int main(void) {
  char word[100];
  scanf("%s", word);
  for (int i = strlen(word) - 1; i >= 0; i--)
    printf("%c", word[i]);
  printf("\n");
  return 0;
}


x86 assembly (clang, -O0):
<main>:
push   %rbp
mov    %rsp,%rbp
sub    $0x80,%rsp
movl   $0x0,-0x4(%rbp)
lea    -0x70(%rbp),%rsi
lea    0xeb3(%rip),%rdi
call   1050 <scanf@plt>
lea    -0x70(%rbp),%rdi
call   1030 <strlen@plt>
sub    $0x1,%eax
mov    %eax,-0x74(%rbp)
cmpl   $0x0,-0x74(%rbp)
jl     1190 <main+0x60>
movslq -0x74(%rbp),%rax
movsbl -0x70(%rbp,%rax,1),%esi
lea    0xe88(%rip),%rdi
mov    $0x0,%al
call   1040 <printf@plt>
mov    -0x74(%rbp),%eax
add    $0xffffffff,%eax
mov    %eax,-0x74(%rbp)
jmp    1161 <main+0x31>
lea    0xe6f(%rip),%rdi
mov    $0x0,%al
call   1040 <printf@plt>
xor    %eax,%eax
add    $0x80,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<main>:
push   %rbx
sub    $0x70,%rsp
lea    0xec4(%rip),%rdi
mov    %rsp,%rbx
mov    %rbx,%rsi
call   1050 <scanf@plt>
mov    %rbx,%rdi
call   1040 <strlen@plt>
test   %eax,%eax
jle    1176 <main+0x46>
mov    %eax,%ebx
add    $0x1,%rbx
nopl   0x0(%rax)
lea    -0x2(%rbx),%eax
movsbl (%rsp,%rax,1),%edi
call   1030 <putchar@plt>
add    $0xffffffffffffffff,%rbx
cmp    $0x1,%rbx
ja     1160 <main+0x30>
mov    $0xa,%edi
call   1030 <putchar@plt>
xor    %eax,%eax
add    $0x70,%rsp
pop    %rbx
ret

LLVM IR (-O0):
@.str = [3 x i8] c"%s\00"
@.str.1 = [3 x i8] c"%c\00"
@.str.2 = [2 x i8] c"\0A\00"
define i32 @main() {
%1 = alloca i32
%2 = alloca [100 x i8]
%3 = alloca i32
store i32 0, i32* %1
%4 = getelementptr inbounds [100 x i8], [100 x i8]* %2, i64 0, i64 0
%5 = call i32 @scanf(i8* getelementptr inbounds ([3 x i8], [3 x i8]* @.str, i64 0, i64 0), i8* %4)
%6 = getelementptr inbounds [100 x i8], [100 x i8]* %2, i64 0, i64 0
%7 = call i32 @strlen(i8* %6)
%8 = sub nsw i32 %7, 1
store i32 %8, i32* %3
br label %9
9: ; preds = %19, %0
%10 = load i32, i32* %3
%11 = icmp sge i32 %10, 0
br i1 %11, label %12, label %22
12: ; preds = %9
%13 = load i32, i32* %3
%14 = sext i32 %13 to i64
%15 = getelementptr inbounds [100 x i8], [100 x i8]* %2, i64 0, i64 %14
%16 = load i8, i8* %15
%17 = sext i8 %16 to i32
%18 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([3 x i8], [3 x i8]* @.str.1, i64 0, i64 0), i32 %17)
br label %19
19: ; preds = %12
%20 = load i32, i32* %3
%21 = add nsw i32 %20, -1
store i32 %21, i32* %3
br label %9
22: ; preds = %9
%23 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([2 x i8], [2 x i8]* @.str.2, i64 0, i64 0))
ret i32 0
}

LLVM IR (-O2):
@.str = [3 x i8] c"%s\00"
define i32 @main() {
%1 = alloca [100 x i8]
%2 = getelementptr inbounds [100 x i8], [100 x i8]* %1, i64 0, i64 0
%3 = call i32 @scanf(i8* getelementptr inbounds ([3 x i8], [3 x i8]* @.str, i64 0, i64 0), i8* %2)
%4 = call i32 @strlen(i8* %2)
%5 = icmp sgt i32 %4, 0
br i1 %5, label %6, label %8
6: ; preds = %0
%7 = zext i32 %4 to i64
br label %10
8: ; preds = %10, %0
%9 = call i32 @putchar(i32 10)
ret i32 0
10: ; preds = %6, %10
%11 = phi i64 [ %7, %6 ], [ %12, %10 ]
%12 = add nsw i64 %11, -1
%13 = and i64 %12, 4294967295
%14 = getelementptr inbounds [100 x i8], [100 x i8]* %1, i64 0, i64 %13
%15 = load i8, i8* %14
%16 = sext i8 %15 to i32
%17 = call i32 @putchar(i32 %16)
%18 = icmp ugt i64 %11, 1
br i1 %18, label %10, label %8
}