#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 *);
scalar_t__ strcat(char *, char *);
int main(int argc, char *argv[]) {
  char str1[128];
  char str2[128];
  printf("please input prefix:");
  scanf("%s", str1);
  printf("please input suffix:");
  scanf("%s", str2);
  if (strcat(str1, str2) != 0) {
    printf("something is wrong!\n");
  } else {
    printf("your lucky string: '%s'\n", str1);
  }
  return 0;
}


x86 assembly (clang, -O0):
<main>:
push   %rbp
mov    %rsp,%rbp
sub    $0x110,%rsp
movl   $0x0,-0x4(%rbp)
mov    %edi,-0x8(%rbp)
mov    %rsi,-0x10(%rbp)
lea    0xeb0(%rip),%rdi
mov    $0x0,%al
call   1030 <printf@plt>
lea    -0x90(%rbp),%rsi
lea    0xeb0(%rip),%rdi
call   1040 <scanf@plt>
lea    0xea7(%rip),%rdi
mov    $0x0,%al
call   1030 <printf@plt>
lea    -0x110(%rbp),%rsi
lea    0xe8f(%rip),%rdi
call   1040 <scanf@plt>
lea    -0x90(%rbp),%rdi
lea    -0x110(%rbp),%rsi
call   1050 <strcat@plt>
cmp    $0x0,%rax
je     11bb <main+0x8b>
lea    0xe7e(%rip),%rdi
mov    $0x0,%al
call   1030 <printf@plt>
jmp    11d0 <main+0xa0>
lea    -0x90(%rbp),%rsi
lea    0xe79(%rip),%rdi
mov    $0x0,%al
call   1030 <printf@plt>
xor    %eax,%eax
add    $0x110,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<main>:
push   %r15
push   %r14
push   %rbx
sub    $0x100,%rsp
lea    0xead(%rip),%rdi
xor    %eax,%eax
call   1040 <printf@plt>
lea    0xeb4(%rip),%r15
mov    %rsp,%r14
mov    %r15,%rdi
mov    %r14,%rsi
call   1050 <scanf@plt>
lea    0xea2(%rip),%rdi
xor    %eax,%eax
call   1040 <printf@plt>
lea    0x80(%rsp),%rbx
mov    %r15,%rdi
mov    %rbx,%rsi
call   1050 <scanf@plt>
mov    %r14,%rdi
mov    %rbx,%rsi
call   1060 <strcat@plt>
test   %rax,%rax
je     11ae <main+0x6e>
lea    0xe9f(%rip),%rdi
call   1030 <puts@plt>
jmp    11bf <main+0x7f>
lea    0xe78(%rip),%rdi
mov    %rsp,%rsi
xor    %eax,%eax
call   1040 <printf@plt>
xor    %eax,%eax
add    $0x100,%rsp
pop    %rbx
pop    %r14
pop    %r15
ret

LLVM IR (-O0):
@.str = [21 x i8] c"please input prefix:\00"
@.str.1 = [3 x i8] c"%s\00"
@.str.2 = [21 x i8] c"please input suffix:\00"
@.str.3 = [21 x i8] c"something is wrong!\0A\00"
@.str.4 = [25 x i8] c"your lucky string: '%s'\0A\00"
define i32 @main(i32 %0, i8** %1) {
%3 = alloca i32
%4 = alloca i32
%5 = alloca i8**
%6 = alloca [128 x i8]
%7 = alloca [128 x i8]
store i32 0, i32* %3
store i32 %0, i32* %4
store i8** %1, i8*** %5
%8 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([21 x i8], [21 x i8]* @.str, i64 0, i64 0))
%9 = getelementptr inbounds [128 x i8], [128 x i8]* %6, i64 0, i64 0
%10 = call i32 @scanf(i8* getelementptr inbounds ([3 x i8], [3 x i8]* @.str.1, i64 0, i64 0), i8* %9)
%11 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([21 x i8], [21 x i8]* @.str.2, i64 0, i64 0))
%12 = getelementptr inbounds [128 x i8], [128 x i8]* %7, i64 0, i64 0
%13 = call i32 @scanf(i8* getelementptr inbounds ([3 x i8], [3 x i8]* @.str.1, i64 0, i64 0), i8* %12)
%14 = getelementptr inbounds [128 x i8], [128 x i8]* %6, i64 0, i64 0
%15 = getelementptr inbounds [128 x i8], [128 x i8]* %7, i64 0, i64 0
%16 = call i64 @strcat(i8* %14, i8* %15)
%17 = icmp ne i64 %16, 0
br i1 %17, label %18, label %20
18: ; preds = %2
%19 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([21 x i8], [21 x i8]* @.str.3, i64 0, i64 0))
br label %23
20: ; preds = %2
%21 = getelementptr inbounds [128 x i8], [128 x i8]* %6, i64 0, i64 0
%22 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([25 x i8], [25 x i8]* @.str.4, i64 0, i64 0), i8* %21)
br label %23
23: ; preds = %20, %18
ret i32 0
}

LLVM IR (-O2):
@.str = [21 x i8] c"please input prefix:\00"
@.str.1 = [3 x i8] c"%s\00"
@.str.2 = [21 x i8] c"please input suffix:\00"
@.str.4 = [25 x i8] c"your lucky string: '%s'\0A\00"
@str = [20 x i8] c"something is wrong!\00"
define i32 @main(i32 %0, i8** nocapture readnone %1) {
%3 = alloca [128 x i8]
%4 = alloca [128 x i8]
%5 = getelementptr inbounds [128 x i8], [128 x i8]* %3, i64 0, i64 0
%6 = getelementptr inbounds [128 x i8], [128 x i8]* %4, i64 0, i64 0
%7 = tail call i32 (i8*, ...) @printf(i8* dereferenceable(1) getelementptr inbounds ([21 x i8], [21 x i8]* @.str, i64 0, i64 0))
%8 = call i32 @scanf(i8* getelementptr inbounds ([3 x i8], [3 x i8]* @.str.1, i64 0, i64 0), i8* %5)
%9 = call i32 (i8*, ...) @printf(i8* dereferenceable(1) getelementptr inbounds ([21 x i8], [21 x i8]* @.str.2, i64 0, i64 0))
%10 = call i32 @scanf(i8* getelementptr inbounds ([3 x i8], [3 x i8]* @.str.1, i64 0, i64 0), i8* %6)
%11 = call i64 @strcat(i8* %5, i8* %6)
%12 = icmp eq i64 %11, 0
br i1 %12, label %15, label %13
13: ; preds = %2
%14 = call i32 @puts(i8* dereferenceable(1) getelementptr inbounds ([20 x i8], [20 x i8]* @str, i64 0, i64 0))
br label %17
15: ; preds = %2
%16 = call i32 (i8*, ...) @printf(i8* dereferenceable(1) getelementptr inbounds ([25 x i8], [25 x i8]* @.str.4, i64 0, i64 0), i8* %5)
br label %17
17: ; preds = %15, %13
ret i32 0
}