#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*/ EXIT_FAILURE;
int /*<<< orphan*/ exit(int /*<<< orphan*/);
int /*<<< orphan*/ fprintf(int /*<<< orphan*/, char *, char *);
int /*<<< orphan*/ printf(char *, char *);
int /*<<< orphan*/ revstr(char *);
int /*<<< orphan*/ stderr;
int main(int argc, char *argv[]) {
  char *str;
  if (argc != 2) {
    fprintf(stderr, "usage: %s <str>\n", argv[0]);
    exit(EXIT_FAILURE);
  }
  str = argv[1];
  revstr(str);
  printf("%s\n", str);
  return 0;
}


x86 assembly (clang, -O0):
<main>:
push   %rbp
mov    %rsp,%rbp
sub    $0x20,%rsp
movl   $0x0,-0x4(%rbp)
mov    %edi,-0x8(%rbp)
mov    %rsi,-0x10(%rbp)
cmpl   $0x2,-0x8(%rbp)
je     118a <main+0x4a>
mov    0x2e79(%rip),%rax
mov    (%rax),%edi
mov    -0x10(%rbp),%rax
mov    (%rax),%rdx
lea    0xe89(%rip),%rsi
call   1050 <fprintf@plt>
mov    0x2e55(%rip),%rax
mov    (%rax),%edi
call   1060 <exit@plt>
mov    -0x10(%rbp),%rax
mov    0x8(%rax),%rax
mov    %rax,-0x18(%rbp)
mov    -0x18(%rbp),%rdi
call   1030 <revstr@plt>
mov    -0x18(%rbp),%rsi
lea    0xe67(%rip),%rdi
call   1040 <printf@plt>
xor    %eax,%eax
add    $0x20,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<main>:
push   %rbx
cmp    $0x2,%edi
jne    1165 <main+0x25>
mov    0x8(%rsi),%rbx
mov    %rbx,%rdi
call   1030 <revstr@plt>
lea    0xeb8(%rip),%rdi
mov    %rbx,%rsi
call   1040 <printf@plt>
xor    %eax,%eax
pop    %rbx
ret
mov    0x2e74(%rip),%rax
mov    (%rax),%edi
mov    (%rsi),%rdx
lea    0xe88(%rip),%rsi
call   1050 <fprintf@plt>
mov    0x2e54(%rip),%rax
mov    (%rax),%edi
call   1060 <exit@plt>

LLVM IR (-O0):
@stderr = global i32 0
@.str = [17 x i8] c"usage: %s <str>\0A\00"
@EXIT_FAILURE = global i32 0
@.str.1 = [4 x i8] c"%s\0A\00"
define i32 @main(i32 %0, i8** %1) {
%3 = alloca i32
%4 = alloca i32
%5 = alloca i8**
%6 = alloca i8*
store i32 0, i32* %3
store i32 %0, i32* %4
store i8** %1, i8*** %5
%7 = load i32, i32* %4
%8 = icmp ne i32 %7, 2
br i1 %8, label %9, label %17
9: ; preds = %2
%10 = load i32, i32* @stderr
%11 = load i8**, i8*** %5
%12 = getelementptr inbounds i8*, i8** %11, i64 0
%13 = load i8*, i8** %12
%14 = call i32 @fprintf(i32 %10, i8* getelementptr inbounds ([17 x i8], [17 x i8]* @.str, i64 0, i64 0), i8* %13)
%15 = load i32, i32* @EXIT_FAILURE
%16 = call i32 @exit(i32 %15)
unreachable
17: ; preds = %2
%18 = load i8**, i8*** %5
%19 = getelementptr inbounds i8*, i8** %18, i64 1
%20 = load i8*, i8** %19
store i8* %20, i8** %6
%21 = load i8*, i8** %6
%22 = call i32 @revstr(i8* %21)
%23 = load i8*, i8** %6
%24 = call i32 @printf(i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str.1, i64 0, i64 0), i8* %23)
ret i32 0
}

LLVM IR (-O2):
@stderr = global i32 0
@.str = [17 x i8] c"usage: %s <str>\0A\00"
@EXIT_FAILURE = global i32 0
@.str.1 = [4 x i8] c"%s\0A\00"
define i32 @main(i32 %0, i8** nocapture %1) {
%3 = icmp eq i32 %0, 2
br i1 %3, label %10, label %4
4: ; preds = %2
%5 = load i32, i32* @stderr
%6 = load i8*, i8** %1
%7 = tail call i32 @fprintf(i32 %5, i8* getelementptr inbounds ([17 x i8], [17 x i8]* @.str, i64 0, i64 0), i8* %6)
%8 = load i32, i32* @EXIT_FAILURE
%9 = tail call i32 @exit(i32 %8)
unreachable
10: ; preds = %2
%11 = getelementptr inbounds i8*, i8** %1, i64 1
%12 = load i8*, i8** %11
%13 = tail call i32 @revstr(i8* %12)
%14 = tail call i32 @printf(i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str.1, i64 0, i64 0), i8* %12)
ret i32 0
}