#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 /*<<< orphan*/ strcat(char *, char *);
int main(void) {
  char a[50];
  char b[50];
  printf("Enter String a:");
  scanf("%s", a);
  printf("Enter String b:");
  scanf("%s", b);
  strcat(a, b);
  printf("%s\n", a);
  return 0;
}


x86 assembly (clang, -O0):
<main>:
push   %rbp
mov    %rsp,%rbp
sub    $0x80,%rsp
movl   $0x0,-0x4(%rbp)
lea    0xeb7(%rip),%rdi
mov    $0x0,%al
call   1030 <printf@plt>
lea    -0x40(%rbp),%rsi
lea    0xeb5(%rip),%rdi
call   1040 <scanf@plt>
lea    0xeac(%rip),%rdi
mov    $0x0,%al
call   1030 <printf@plt>
lea    -0x80(%rbp),%rsi
lea    0xe97(%rip),%rdi
call   1040 <scanf@plt>
lea    -0x40(%rbp),%rdi
lea    -0x80(%rbp),%rsi
call   1050 <strcat@plt>
lea    -0x40(%rbp),%rsi
lea    0xe8d(%rip),%rdi
mov    $0x0,%al
call   1030 <printf@plt>
xor    %eax,%eax
add    $0x80,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<main>:
push   %r15
push   %r14
push   %rbx
sub    $0x80,%rsp
lea    0xead(%rip),%rdi
xor    %eax,%eax
call   1040 <printf@plt>
lea    0xeaf(%rip),%r14
lea    0x40(%rsp),%r15
mov    %r14,%rdi
mov    %r15,%rsi
call   1050 <scanf@plt>
lea    0xe9b(%rip),%rdi
xor    %eax,%eax
call   1040 <printf@plt>
mov    %rsp,%rbx
mov    %r14,%rdi
mov    %rbx,%rsi
call   1050 <scanf@plt>
mov    %r15,%rdi
mov    %rbx,%rsi
call   1060 <strcat@plt>
mov    %r15,%rdi
call   1030 <puts@plt>
xor    %eax,%eax
add    $0x80,%rsp
pop    %rbx
pop    %r14
pop    %r15
ret

LLVM IR (-O0):
@.str = [16 x i8] c"Enter String a:\00"
@.str.1 = [3 x i8] c"%s\00"
@.str.2 = [16 x i8] c"Enter String b:\00"
@.str.3 = [4 x i8] c"%s\0A\00"
define i32 @main() {
%1 = alloca i32
%2 = alloca [50 x i8]
%3 = alloca [50 x i8]
store i32 0, i32* %1
%4 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([16 x i8], [16 x i8]* @.str, i64 0, i64 0))
%5 = getelementptr inbounds [50 x i8], [50 x i8]* %2, i64 0, i64 0
%6 = call i32 @scanf(i8* getelementptr inbounds ([3 x i8], [3 x i8]* @.str.1, i64 0, i64 0), i8* %5)
%7 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([16 x i8], [16 x i8]* @.str.2, i64 0, i64 0))
%8 = getelementptr inbounds [50 x i8], [50 x i8]* %3, i64 0, i64 0
%9 = call i32 @scanf(i8* getelementptr inbounds ([3 x i8], [3 x i8]* @.str.1, i64 0, i64 0), i8* %8)
%10 = getelementptr inbounds [50 x i8], [50 x i8]* %2, i64 0, i64 0
%11 = getelementptr inbounds [50 x i8], [50 x i8]* %3, i64 0, i64 0
%12 = call i32 @strcat(i8* %10, i8* %11)
%13 = getelementptr inbounds [50 x i8], [50 x i8]* %2, i64 0, i64 0
%14 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str.3, i64 0, i64 0), i8* %13)
ret i32 0
}

LLVM IR (-O2):
@.str = [16 x i8] c"Enter String a:\00"
@.str.1 = [3 x i8] c"%s\00"
@.str.2 = [16 x i8] c"Enter String b:\00"
define i32 @main() {
%1 = alloca [50 x i8]
%2 = alloca [50 x i8]
%3 = getelementptr inbounds [50 x i8], [50 x i8]* %1, i64 0, i64 0
%4 = getelementptr inbounds [50 x i8], [50 x i8]* %2, i64 0, i64 0
%5 = tail call i32 (i8*, ...) @printf(i8* dereferenceable(1) getelementptr inbounds ([16 x i8], [16 x i8]* @.str, i64 0, i64 0))
%6 = call i32 @scanf(i8* getelementptr inbounds ([3 x i8], [3 x i8]* @.str.1, i64 0, i64 0), i8* %3)
%7 = call i32 (i8*, ...) @printf(i8* dereferenceable(1) getelementptr inbounds ([16 x i8], [16 x i8]* @.str.2, i64 0, i64 0))
%8 = call i32 @scanf(i8* getelementptr inbounds ([3 x i8], [3 x i8]* @.str.1, i64 0, i64 0), i8* %4)
%9 = call i32 @strcat(i8* %3, i8* %4)
%10 = call i32 @puts(i8* %3)
ret i32 0
}