#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*/ getchar();
int /*<<< orphan*/ getline(char *, int);
int /*<<< orphan*/ printf(char *, ...);
int /*<<< orphan*/ strcaat(char *, char *);
int main() {
  char a[100];
  char b[100];
  printf("Enter first string\n");
  getline(a, 100);
  printf("Enter second string\n");
  getline(b, 100);
  strcaat(a, b);
  printf("%s", a);
  getchar();
  return 0;
}


x86 assembly (clang, -O0):
<main>:
push   %rbp
mov    %rsp,%rbp
sub    $0xe0,%rsp
movl   $0x0,-0x4(%rbp)
lea    0xea7(%rip),%rdi
mov    $0x0,%al
call   1040 <printf@plt>
lea    -0x70(%rbp),%rdi
mov    $0x64,%esi
call   1060 <getline@plt>
lea    0xe9f(%rip),%rdi
mov    $0x0,%al
call   1040 <printf@plt>
lea    -0xe0(%rbp),%rdi
mov    $0x64,%esi
call   1060 <getline@plt>
lea    -0x70(%rbp),%rdi
lea    -0xe0(%rbp),%rsi
call   1030 <strcaat@plt>
lea    -0x70(%rbp),%rsi
lea    0xe81(%rip),%rdi
mov    $0x0,%al
call   1040 <printf@plt>
mov    $0x0,%al
call   1050 <getchar@plt>
xor    %eax,%eax
add    $0xe0,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<main>:
push   %r14
push   %rbx
sub    $0xd8,%rsp
lea    0xea2(%rip),%rdi
call   1030 <puts@plt>
lea    0x70(%rsp),%r14
mov    %r14,%rdi
mov    $0x64,%esi
call   1070 <getline@plt>
lea    0xe97(%rip),%rdi
call   1030 <puts@plt>
mov    %rsp,%rbx
mov    %rbx,%rdi
mov    $0x64,%esi
call   1070 <getline@plt>
mov    %r14,%rdi
mov    %rbx,%rsi
call   1040 <strcaat@plt>
lea    0xe5a(%rip),%rdi
mov    %r14,%rsi
xor    %eax,%eax
call   1050 <printf@plt>
xor    %eax,%eax
call   1060 <getchar@plt>
xor    %eax,%eax
add    $0xd8,%rsp
pop    %rbx
pop    %r14
ret

LLVM IR (-O0):
@.str = [20 x i8] c"Enter first string\0A\00"
@.str.1 = [21 x i8] c"Enter second string\0A\00"
@.str.2 = [3 x i8] c"%s\00"
define i32 @main() {
%1 = alloca i32
%2 = alloca [100 x i8]
%3 = alloca [100 x i8]
store i32 0, i32* %1
%4 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([20 x i8], [20 x i8]* @.str, i64 0, i64 0))
%5 = getelementptr inbounds [100 x i8], [100 x i8]* %2, i64 0, i64 0
%6 = call i32 @getline(i8* %5, i32 100)
%7 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([21 x i8], [21 x i8]* @.str.1, i64 0, i64 0))
%8 = getelementptr inbounds [100 x i8], [100 x i8]* %3, i64 0, i64 0
%9 = call i32 @getline(i8* %8, i32 100)
%10 = getelementptr inbounds [100 x i8], [100 x i8]* %2, i64 0, i64 0
%11 = getelementptr inbounds [100 x i8], [100 x i8]* %3, i64 0, i64 0
%12 = call i32 @strcaat(i8* %10, i8* %11)
%13 = getelementptr inbounds [100 x i8], [100 x i8]* %2, i64 0, i64 0
%14 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([3 x i8], [3 x i8]* @.str.2, i64 0, i64 0), i8* %13)
%15 = call i32 (...) @getchar()
ret i32 0
}

LLVM IR (-O2):
@.str.2 = [3 x i8] c"%s\00"
@str = [19 x i8] c"Enter first string\00"
@str.3 = [20 x i8] c"Enter second string\00"
define i32 @main() {
%1 = alloca [100 x i8]
%2 = alloca [100 x i8]
%3 = getelementptr inbounds [100 x i8], [100 x i8]* %1, i64 0, i64 0
%4 = getelementptr inbounds [100 x i8], [100 x i8]* %2, i64 0, i64 0
%5 = tail call i32 @puts(i8* dereferenceable(1) getelementptr inbounds ([19 x i8], [19 x i8]* @str, i64 0, i64 0))
%6 = call i32 @getline(i8* %3, i32 100)
%7 = call i32 @puts(i8* dereferenceable(1) getelementptr inbounds ([20 x i8], [20 x i8]* @str.3, i64 0, i64 0))
%8 = call i32 @getline(i8* %4, i32 100)
%9 = call i32 @strcaat(i8* %3, i8* %4)
%10 = call i32 (i8*, ...) @printf(i8* dereferenceable(1) getelementptr inbounds ([3 x i8], [3 x i8]* @.str.2, i64 0, i64 0), i8* %3)
%11 = call i32 (...) @getchar()
ret i32 0
}