#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 int /*<<< orphan*/ str;

/* Variables and functions */
int /*<<< orphan*/ do_reverse(char *);
int /*<<< orphan*/ fgets(char *, int, int /*<<< orphan*/);
int /*<<< orphan*/ printf(char *, ...);
int /*<<< orphan*/ stdin;
int strlen(char *);
int main(int argc, char **argv) {
  char str[128];
  printf("input a string...\n");
  fgets(str, sizeof(str), stdin);
  str[strlen(str) - 1] = '\0';
  do_reverse(str);
  printf("the reverse of your input string is:\n%s\n", str);
  return 0;
}


x86 assembly (clang, -O0):
<main>:
push   %rbp
mov    %rsp,%rbp
sub    $0x90,%rsp
movl   $0x0,-0x4(%rbp)
mov    %edi,-0x8(%rbp)
mov    %rsi,-0x10(%rbp)
lea    0xea0(%rip),%rdi
mov    $0x0,%al
call   1040 <printf@plt>
lea    -0x90(%rbp),%rdi
mov    0x2e73(%rip),%rax
mov    (%rax),%edx
mov    $0x80,%esi
call   1050 <fgets@plt>
lea    -0x90(%rbp),%rdi
call   1030 <strlen@plt>
sub    $0x1,%eax
cltq
movb   $0x0,-0x90(%rbp,%rax,1)
lea    -0x90(%rbp),%rdi
call   1060 <do_reverse@plt>
lea    -0x90(%rbp),%rsi
lea    0xe5f(%rip),%rdi
mov    $0x0,%al
call   1040 <printf@plt>
xor    %eax,%eax
add    $0x90,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<main>:
push   %rbx
sub    $0x80,%rsp
lea    0xeca(%rip),%rdi
call   1030 <puts@plt>
mov    0x2e7d(%rip),%rax
mov    (%rax),%edx
mov    %rsp,%rbx
mov    %rbx,%rdi
mov    $0x80,%esi
call   1060 <fgets@plt>
mov    %rbx,%rdi
call   1040 <strlen@plt>
cltq
movb   $0x0,-0x1(%rax,%rbx,1)
mov    %rbx,%rdi
call   1070 <do_reverse@plt>
lea    0xe65(%rip),%rdi
mov    %rbx,%rsi
xor    %eax,%eax
call   1050 <printf@plt>
xor    %eax,%eax
add    $0x80,%rsp
pop    %rbx
ret

LLVM IR (-O0):
@.str = [19 x i8] c"input a string...\0A\00"
@stdin = global i32 0
@.str.1 = [41 x i8] c"the reverse of your input string is:\0A%s\0A\00"
define i32 @main(i32 %0, i8** %1) {
%3 = alloca i32
%4 = alloca i32
%5 = alloca i8**
%6 = alloca [128 x i8]
store i32 0, i32* %3
store i32 %0, i32* %4
store i8** %1, i8*** %5
%7 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([19 x i8], [19 x i8]* @.str, i64 0, i64 0))
%8 = getelementptr inbounds [128 x i8], [128 x i8]* %6, i64 0, i64 0
%9 = load i32, i32* @stdin
%10 = call i32 @fgets(i8* %8, i32 128, i32 %9)
%11 = getelementptr inbounds [128 x i8], [128 x i8]* %6, i64 0, i64 0
%12 = call i32 @strlen(i8* %11)
%13 = sub nsw i32 %12, 1
%14 = sext i32 %13 to i64
%15 = getelementptr inbounds [128 x i8], [128 x i8]* %6, i64 0, i64 %14
store i8 0, i8* %15
%16 = getelementptr inbounds [128 x i8], [128 x i8]* %6, i64 0, i64 0
%17 = call i32 @do_reverse(i8* %16)
%18 = getelementptr inbounds [128 x i8], [128 x i8]* %6, i64 0, i64 0
%19 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([41 x i8], [41 x i8]* @.str.1, i64 0, i64 0), i8* %18)
ret i32 0
}

LLVM IR (-O2):
@stdin = global i32 0
@.str.1 = [41 x i8] c"the reverse of your input string is:\0A%s\0A\00"
@str = [18 x i8] c"input a string...\00"
define i32 @main(i32 %0, i8** nocapture readnone %1) {
%3 = alloca [128 x i8]
%4 = getelementptr inbounds [128 x i8], [128 x i8]* %3, i64 0, i64 0
%5 = tail call i32 @puts(i8* dereferenceable(1) getelementptr inbounds ([18 x i8], [18 x i8]* @str, i64 0, i64 0))
%6 = load i32, i32* @stdin
%7 = call i32 @fgets(i8* %4, i32 128, i32 %6)
%8 = call i32 @strlen(i8* %4)
%9 = add nsw i32 %8, -1
%10 = sext i32 %9 to i64
%11 = getelementptr inbounds [128 x i8], [128 x i8]* %3, i64 0, i64 %10
store i8 0, i8* %11
%12 = call i32 @do_reverse(i8* %4)
%13 = call i32 (i8*, ...) @printf(i8* dereferenceable(1) getelementptr inbounds ([41 x i8], [41 x i8]* @.str.1, i64 0, i64 0), i8* %4)
ret i32 0
}