#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*/ gets(char *);
int /*<<< orphan*/ printf(char *, ...);
int /*<<< orphan*/ strcpy(char *, char *);
int main(void) {
  char a[80 + 1], b[80 + 1], c[80 + 1];
  printf("Introduce un texto (max %d cars.): ", 80);
  gets(a);
  printf("Introduce otro texto (max %d cars.): ", 80);
  gets(b);
  strcpy(c, a);
  strcpy(c, b);
  printf("Concatenacion de ambos: %s", c);
  return 0;
}


x86 assembly (clang, -O0):
<main>:
push   %rbp
mov    %rsp,%rbp
sub    $0x120,%rsp
movl   $0x0,-0x4(%rbp)
lea    0xeb7(%rip),%rdi
mov    $0x50,%esi
mov    $0x0,%al
call   1040 <printf@plt>
lea    -0x60(%rbp),%rdi
call   1050 <gets@plt>
lea    0xebf(%rip),%rdi
mov    $0x50,%esi
mov    $0x0,%al
call   1040 <printf@plt>
lea    -0xc0(%rbp),%rdi
call   1050 <gets@plt>
lea    -0x120(%rbp),%rdi
lea    -0x60(%rbp),%rsi
call   1030 <strcpy@plt>
lea    -0x120(%rbp),%rdi
lea    -0xc0(%rbp),%rsi
call   1030 <strcpy@plt>
lea    -0x120(%rbp),%rsi
lea    0xe9c(%rip),%rdi
mov    $0x0,%al
call   1040 <printf@plt>
xor    %eax,%eax
add    $0x120,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<main>:
push   %r15
push   %r14
push   %rbx
sub    $0x120,%rsp
lea    0xebd(%rip),%rdi
mov    $0x50,%esi
xor    %eax,%eax
call   1040 <printf@plt>
lea    0xc0(%rsp),%r14
mov    %r14,%rdi
call   1050 <gets@plt>
lea    0xebe(%rip),%rdi
mov    $0x50,%esi
xor    %eax,%eax
call   1040 <printf@plt>
lea    0x60(%rsp),%r15
mov    %r15,%rdi
call   1050 <gets@plt>
mov    %rsp,%rbx
mov    %rbx,%rdi
mov    %r14,%rsi
call   1030 <strcpy@plt>
mov    %rbx,%rdi
mov    %r15,%rsi
call   1030 <strcpy@plt>
lea    0xeab(%rip),%rdi
mov    %rbx,%rsi
xor    %eax,%eax
call   1040 <printf@plt>
xor    %eax,%eax
add    $0x120,%rsp
pop    %rbx
pop    %r14
pop    %r15
ret

LLVM IR (-O0):
@.str = [36 x i8] c"Introduce un texto (max %d cars.): \00"
@.str.1 = [38 x i8] c"Introduce otro texto (max %d cars.): \00"
@.str.2 = [27 x i8] c"Concatenacion de ambos: %s\00"
define i32 @main() {
%1 = alloca i32
%2 = alloca [81 x i8]
%3 = alloca [81 x i8]
%4 = alloca [81 x i8]
store i32 0, i32* %1
%5 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([36 x i8], [36 x i8]* @.str, i64 0, i64 0), i32 80)
%6 = getelementptr inbounds [81 x i8], [81 x i8]* %2, i64 0, i64 0
%7 = call i32 @gets(i8* %6)
%8 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([38 x i8], [38 x i8]* @.str.1, i64 0, i64 0), i32 80)
%9 = getelementptr inbounds [81 x i8], [81 x i8]* %3, i64 0, i64 0
%10 = call i32 @gets(i8* %9)
%11 = getelementptr inbounds [81 x i8], [81 x i8]* %4, i64 0, i64 0
%12 = getelementptr inbounds [81 x i8], [81 x i8]* %2, i64 0, i64 0
%13 = call i32 @strcpy(i8* %11, i8* %12)
%14 = getelementptr inbounds [81 x i8], [81 x i8]* %4, i64 0, i64 0
%15 = getelementptr inbounds [81 x i8], [81 x i8]* %3, i64 0, i64 0
%16 = call i32 @strcpy(i8* %14, i8* %15)
%17 = getelementptr inbounds [81 x i8], [81 x i8]* %4, i64 0, i64 0
%18 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([27 x i8], [27 x i8]* @.str.2, i64 0, i64 0), i8* %17)
ret i32 0
}

LLVM IR (-O2):
@.str = [36 x i8] c"Introduce un texto (max %d cars.): \00"
@.str.1 = [38 x i8] c"Introduce otro texto (max %d cars.): \00"
@.str.2 = [27 x i8] c"Concatenacion de ambos: %s\00"
define i32 @main() {
%1 = alloca [81 x i8]
%2 = alloca [81 x i8]
%3 = alloca [81 x i8]
%4 = getelementptr inbounds [81 x i8], [81 x i8]* %1, i64 0, i64 0
%5 = getelementptr inbounds [81 x i8], [81 x i8]* %2, i64 0, i64 0
%6 = getelementptr inbounds [81 x i8], [81 x i8]* %3, i64 0, i64 0
%7 = tail call i32 (i8*, ...) @printf(i8* dereferenceable(1) getelementptr inbounds ([36 x i8], [36 x i8]* @.str, i64 0, i64 0), i32 80)
%8 = call i32 @gets(i8* %4)
%9 = call i32 (i8*, ...) @printf(i8* dereferenceable(1) getelementptr inbounds ([38 x i8], [38 x i8]* @.str.1, i64 0, i64 0), i32 80)
%10 = call i32 @gets(i8* %5)
%11 = call i32 @strcpy(i8* %6, i8* %4)
%12 = call i32 @strcpy(i8* %6, i8* %5)
%13 = call i32 (i8*, ...) @printf(i8* dereferenceable(1) getelementptr inbounds ([27 x i8], [27 x i8]* @.str.2, i64 0, i64 0), i8* %6)
ret i32 0
}