#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 */
typedef int /*<<< orphan*/ FILE;

/* Variables and functions */
int /*<<< orphan*/ *fopen(char *, char *);
int /*<<< orphan*/ strcat(char *, char *);
int /*<<< orphan*/ strcpy(char *, char *);
scalar_t__ strlen(char *);
FILE *concat_fopen(char *s1, char *s2, char *mode) {
  char str[strlen(s1) + strlen(s2) + 1];
  strcpy(str, s1);
  strcat(str, s2);
  return fopen(str, mode);
}


x86 assembly (clang, -O0):
<concat_fopen>:
push   %rbp
mov    %rsp,%rbp
sub    $0x40,%rsp
mov    %rdi,-0x8(%rbp)
mov    %rsi,-0x10(%rbp)
mov    %rdx,-0x18(%rbp)
mov    -0x8(%rbp),%rdi
call   1040 <strlen@plt>
mov    %rax,-0x38(%rbp)
mov    -0x10(%rbp),%rdi
call   1040 <strlen@plt>
mov    -0x38(%rbp),%rcx
mov    %rax,%rdx
lea    0x1(%rcx,%rdx,1),%rax
mov    %rsp,%rsi
mov    %rsi,-0x20(%rbp)
lea    0x10(%rcx,%rdx,1),%rcx
and    $0xfffffffffffffff0,%rcx
mov    %rsp,%rdi
sub    %rcx,%rdi
mov    %rdi,-0x30(%rbp)
mov    %rdi,%rsp
mov    %rax,-0x28(%rbp)
mov    -0x8(%rbp),%rsi
call   1030 <strcpy@plt>
mov    -0x30(%rbp),%rdi
mov    -0x10(%rbp),%rsi
call   1060 <strcat@plt>
mov    -0x30(%rbp),%rdi
mov    -0x18(%rbp),%rsi
call   1050 <fopen@plt>
mov    -0x20(%rbp),%rcx
mov    %rcx,%rsp
mov    %rbp,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<concat_fopen>:
push   %rbp
mov    %rsp,%rbp
push   %r15
push   %r14
push   %r12
push   %rbx
mov    %rdx,%r14
mov    %rsi,%r15
mov    %rdi,%r12
call   1040 <strlen@plt>
mov    %rax,%rbx
mov    %r15,%rdi
call   1040 <strlen@plt>
add    %rbx,%rax
add    $0x10,%rax
and    $0xfffffffffffffff0,%rax
mov    %rsp,%rbx
sub    %rax,%rbx
mov    %rbx,%rsp
mov    %rbx,%rdi
mov    %r12,%rsi
call   1030 <strcpy@plt>
mov    %rbx,%rdi
mov    %r15,%rsi
call   1060 <strcat@plt>
mov    %rbx,%rdi
mov    %r14,%rsi
call   1050 <fopen@plt>
lea    -0x20(%rbp),%rsp
pop    %rbx
pop    %r12
pop    %r14
pop    %r15
pop    %rbp
ret

LLVM IR (-O0):
define i32* @concat_fopen(i8* %0, i8* %1, i8* %2) {
%4 = alloca i8*
%5 = alloca i8*
%6 = alloca i8*
%7 = alloca i8*
%8 = alloca i64
store i8* %0, i8** %4
store i8* %1, i8** %5
store i8* %2, i8** %6
%9 = load i8*, i8** %4
%10 = call i64 @strlen(i8* %9)
%11 = load i8*, i8** %5
%12 = call i64 @strlen(i8* %11)
%13 = add nsw i64 %10, %12
%14 = add nsw i64 %13, 1
%15 = call i8* @llvm.stacksave()
store i8* %15, i8** %7
%16 = alloca i8, i64 %14
store i64 %14, i64* %8
%17 = load i8*, i8** %4
%18 = call i32 @strcpy(i8* %16, i8* %17)
%19 = load i8*, i8** %5
%20 = call i32 @strcat(i8* %16, i8* %19)
%21 = load i8*, i8** %6
%22 = call i32* @fopen(i8* %16, i8* %21)
%23 = load i8*, i8** %7
ret i32* %22
}

LLVM IR (-O2):
define noalias i32* @concat_fopen(i8* %0, i8* %1, i8* nocapture %2) {
%4 = tail call i64 @strlen(i8* dereferenceable(1) %0)
%5 = tail call i64 @strlen(i8* dereferenceable(1) %1)
%6 = add i64 %4, 1
%7 = add i64 %6, %5
%8 = alloca i8, i64 %7
%9 = call i32 @strcpy(i8* %8, i8* %0)
%10 = call i32 @strcat(i8* %8, i8* %1)
%11 = call i32* @fopen(i8* %8, i8* %2)
ret i32* %11
}