#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*/ free(char *);
char *malloc(scalar_t__);
int /*<<< orphan*/ strcat(int /*<<< orphan*/, char *);
int /*<<< orphan*/ strcpy(char *, char *);
scalar_t__ strlen(char *);
FILE *open_ext(char *base, char *ext) {
  char *fn = malloc(strlen(base) + strlen(ext) + 1);
  FILE *f;
  strcat(strcpy(fn, base), ext);
  f = fopen(fn, "w");
  free(fn);
  return f;
}


x86 assembly (clang, -O0):
<open_ext>:
push   %rbp
mov    %rsp,%rbp
sub    $0x30,%rsp
mov    %rdi,-0x8(%rbp)
mov    %rsi,-0x10(%rbp)
mov    -0x8(%rbp),%rdi
call   1050 <strlen@plt>
mov    %rax,-0x28(%rbp)
mov    -0x10(%rbp),%rdi
call   1050 <strlen@plt>
mov    -0x28(%rbp),%rdi
add    %rax,%rdi
add    $0x1,%rdi
call   1060 <malloc@plt>
mov    %rax,-0x18(%rbp)
mov    -0x18(%rbp),%rdi
mov    -0x8(%rbp),%rsi
call   1040 <strcpy@plt>
mov    %eax,%edi
mov    -0x10(%rbp),%rsi
call   1080 <strcat@plt>
mov    -0x18(%rbp),%rdi
lea    0xe43(%rip),%rsi
call   1070 <fopen@plt>
mov    %rax,-0x20(%rbp)
mov    -0x18(%rbp),%rdi
call   1030 <free@plt>
mov    -0x20(%rbp),%rax
add    $0x30,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<open_ext>:
push   %r15
push   %r14
push   %r12
push   %rbx
push   %rax
mov    %rsi,%r14
mov    %rdi,%r12
call   1050 <strlen@plt>
mov    %rax,%r15
mov    %r14,%rdi
call   1050 <strlen@plt>
lea    (%r15,%rax,1),%rdi
add    $0x1,%rdi
call   1060 <malloc@plt>
mov    %rax,%rbx
mov    %rax,%rdi
mov    %r12,%rsi
call   1040 <strcpy@plt>
mov    %eax,%edi
mov    %r14,%rsi
call   1080 <strcat@plt>
lea    0xe56(%rip),%rsi
mov    %rbx,%rdi
call   1070 <fopen@plt>
mov    %rax,%r14
mov    %rbx,%rdi
call   1030 <free@plt>
mov    %r14,%rax
add    $0x8,%rsp
pop    %rbx
pop    %r12
pop    %r14
pop    %r15
ret

LLVM IR (-O0):
@.str = [2 x i8] c"w\00"
define i32* @open_ext(i8* %0, i8* %1) {
%3 = alloca i8*
%4 = alloca i8*
%5 = alloca i8*
%6 = alloca i32*
store i8* %0, i8** %3
store i8* %1, i8** %4
%7 = load i8*, i8** %3
%8 = call i64 @strlen(i8* %7)
%9 = load i8*, i8** %4
%10 = call i64 @strlen(i8* %9)
%11 = add nsw i64 %8, %10
%12 = add nsw i64 %11, 1
%13 = call i8* @malloc(i64 %12)
store i8* %13, i8** %5
%14 = load i8*, i8** %5
%15 = load i8*, i8** %3
%16 = call i32 @strcpy(i8* %14, i8* %15)
%17 = load i8*, i8** %4
%18 = call i32 @strcat(i32 %16, i8* %17)
%19 = load i8*, i8** %5
%20 = call i32* @fopen(i8* %19, i8* getelementptr inbounds ([2 x i8], [2 x i8]* @.str, i64 0, i64 0))
store i32* %20, i32** %6
%21 = load i8*, i8** %5
%22 = call i32 @free(i8* %21)
%23 = load i32*, i32** %6
ret i32* %23
}

LLVM IR (-O2):
@.str = [2 x i8] c"w\00"
define noalias i32* @open_ext(i8* %0, i8* %1) {
%3 = tail call i64 @strlen(i8* dereferenceable(1) %0)
%4 = tail call i64 @strlen(i8* dereferenceable(1) %1)
%5 = add i64 %3, 1
%6 = add i64 %5, %4
%7 = tail call i8* @malloc(i64 %6)
%8 = tail call i32 @strcpy(i8* %7, i8* %0)
%9 = tail call i32 @strcat(i32 %8, i8* %1)
%10 = tail call i32* @fopen(i8* %7, i8* getelementptr inbounds ([2 x i8], [2 x i8]* @.str, i64 0, i64 0))
%11 = tail call i32 @free(i8* %7)
ret i32* %10
}