#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 off_t;

/* Variables and functions */
int /*<<< orphan*/ O_RDWR;
int atoi(char *);
int /*<<< orphan*/ close(int);
int /*<<< orphan*/ fprintf(int /*<<< orphan*/, char *, char *);
scalar_t__ ftruncate(int, int);
int open(char *, int /*<<< orphan*/);
int /*<<< orphan*/ perror(char *);
int /*<<< orphan*/ printf(char *, int);
int /*<<< orphan*/ stderr;
int main(int argc, char *argv[]) {
  if (argc != 3) {
    fprintf(stderr, "Usage: %s <file_name> <size>\n", argv[0]);
    return -1;
  }
  int fd = open(argv[1], O_RDWR);
  if (fd == -1) {
    perror("open");
    return -1;
  }
  off_t size = atoi(argv[2]) * 1024 * 1024;
  printf("Change file size to %ld\n", size);
  if (ftruncate(fd, size) != 0) {
    perror("ftruncate");
    return -1;
  }
  close(fd);
  return 0;
}


x86 assembly (clang, -O0):
<main>:
push   %rbp
mov    %rsp,%rbp
sub    $0x20,%rsp
movl   $0x0,-0x4(%rbp)
mov    %edi,-0x8(%rbp)
mov    %rsi,-0x10(%rbp)
cmpl   $0x3,-0x8(%rbp)
je     11b8 <main+0x48>
mov    0x2e41(%rip),%rax
mov    (%rax),%edi
mov    -0x10(%rbp),%rax
mov    (%rax),%rdx
lea    0xe59(%rip),%rsi
call   1060 <fprintf@plt>
movl   $0xffffffff,-0x4(%rbp)
jmp    1254 <main+0xe4>
mov    -0x10(%rbp),%rax
mov    0x8(%rax),%rdi
mov    0x2e21(%rip),%rax
mov    (%rax),%esi
call   1070 <open@plt>
mov    %eax,-0x14(%rbp)
cmpl   $0xffffffff,-0x14(%rbp)
jne    11f3 <main+0x83>
lea    0xe3c(%rip),%rdi
call   1080 <perror@plt>
movl   $0xffffffff,-0x4(%rbp)
jmp    1254 <main+0xe4>
mov    -0x10(%rbp),%rax
mov    0x10(%rax),%rdi
call   1090 <atoi@plt>
shl    $0xa,%eax
shl    $0xa,%eax
mov    %eax,-0x18(%rbp)
mov    -0x18(%rbp),%esi
lea    0xe10(%rip),%rdi
call   1030 <printf@plt>
mov    -0x14(%rbp),%edi
mov    -0x18(%rbp),%esi
call   1040 <ftruncate@plt>
cmp    $0x0,%rax
je     1245 <main+0xd5>
lea    0xe08(%rip),%rdi
call   1080 <perror@plt>
movl   $0xffffffff,-0x4(%rbp)
jmp    1254 <main+0xe4>
mov    -0x14(%rbp),%edi
call   1050 <close@plt>
movl   $0x0,-0x4(%rbp)
mov    -0x4(%rbp),%eax
add    $0x20,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<main>:
push   %rbp
push   %rbx
push   %rax
mov    %rsi,%rbx
cmp    $0x3,%edi
jne    11c9 <main+0x59>
mov    0x8(%rbx),%rdi
mov    0x2e62(%rip),%rax
mov    (%rax),%esi
call   1070 <open@plt>
cmp    $0xffffffff,%eax
je     11ed <main+0x7d>
mov    %eax,%ebp
mov    0x10(%rbx),%rdi
call   1090 <atoi@plt>
mov    %eax,%ebx
shl    $0x14,%ebx
lea    0xe7a(%rip),%rdi
mov    %ebx,%esi
call   1030 <printf@plt>
mov    %ebp,%edi
mov    %ebx,%esi
call   1040 <ftruncate@plt>
test   %rax,%rax
jne    11f6 <main+0x86>
mov    %ebp,%edi
call   1050 <close@plt>
xor    %eax,%eax
jmp    11e6 <main+0x76>
mov    0x2e08(%rip),%rax
mov    (%rax),%edi
mov    (%rbx),%rdx
lea    0xe24(%rip),%rsi
call   1060 <fprintf@plt>
mov    $0xffffffff,%eax
add    $0x8,%rsp
pop    %rbx
pop    %rbp
ret
lea    0xe2a(%rip),%rdi
jmp    11fd <main+0x8d>
lea    0xe3f(%rip),%rdi
call   1080 <perror@plt>
jmp    11e1 <main+0x71>

LLVM IR (-O0):
@stderr = global i32 0
@.str = [30 x i8] c"Usage: %s <file_name> <size>\0A\00"
@O_RDWR = global i32 0
@.str.1 = [5 x i8] c"open\00"
@.str.2 = [25 x i8] c"Change file size to %ld\0A\00"
@.str.3 = [10 x i8] c"ftruncate\00"
define i32 @main(i32 %0, i8** %1) {
%3 = alloca i32
%4 = alloca i32
%5 = alloca i8**
%6 = alloca i32
%7 = alloca i32
store i32 0, i32* %3
store i32 %0, i32* %4
store i8** %1, i8*** %5
%8 = load i32, i32* %4
%9 = icmp ne i32 %8, 3
br i1 %9, label %10, label %16
10: ; preds = %2
%11 = load i32, i32* @stderr
%12 = load i8**, i8*** %5
%13 = getelementptr inbounds i8*, i8** %12, i64 0
%14 = load i8*, i8** %13
%15 = call i32 @fprintf(i32 %11, i8* getelementptr inbounds ([30 x i8], [30 x i8]* @.str, i64 0, i64 0), i8* %14)
store i32 -1, i32* %3
br label %44
16: ; preds = %2
%17 = load i8**, i8*** %5
%18 = getelementptr inbounds i8*, i8** %17, i64 1
%19 = load i8*, i8** %18
%20 = load i32, i32* @O_RDWR
%21 = call i32 @open(i8* %19, i32 %20)
store i32 %21, i32* %6
%22 = load i32, i32* %6
%23 = icmp eq i32 %22, -1
br i1 %23, label %24, label %26
24: ; preds = %16
%25 = call i32 @perror(i8* getelementptr inbounds ([5 x i8], [5 x i8]* @.str.1, i64 0, i64 0))
store i32 -1, i32* %3
br label %44
26: ; preds = %16
%27 = load i8**, i8*** %5
%28 = getelementptr inbounds i8*, i8** %27, i64 2
%29 = load i8*, i8** %28
%30 = call i32 @atoi(i8* %29)
%31 = mul nsw i32 %30, 1024
%32 = mul nsw i32 %31, 1024
store i32 %32, i32* %7
%33 = load i32, i32* %7
%34 = call i32 @printf(i8* getelementptr inbounds ([25 x i8], [25 x i8]* @.str.2, i64 0, i64 0), i32 %33)
%35 = load i32, i32* %6
%36 = load i32, i32* %7
%37 = call i64 @ftruncate(i32 %35, i32 %36)
%38 = icmp ne i64 %37, 0
br i1 %38, label %39, label %41
39: ; preds = %26
%40 = call i32 @perror(i8* getelementptr inbounds ([10 x i8], [10 x i8]* @.str.3, i64 0, i64 0))
store i32 -1, i32* %3
br label %44
41: ; preds = %26
%42 = load i32, i32* %6
%43 = call i32 @close(i32 %42)
store i32 0, i32* %3
br label %44
44: ; preds = %41, %39, %24, %10
%45 = load i32, i32* %3
ret i32 %45
}

LLVM IR (-O2):
@stderr = global i32 0
@.str = [30 x i8] c"Usage: %s <file_name> <size>\0A\00"
@O_RDWR = global i32 0
@.str.1 = [5 x i8] c"open\00"
@.str.2 = [25 x i8] c"Change file size to %ld\0A\00"
@.str.3 = [10 x i8] c"ftruncate\00"
define i32 @main(i32 %0, i8** nocapture %1) {
%3 = icmp eq i32 %0, 3
br i1 %3, label %8, label %4
4: ; preds = %2
%5 = load i32, i32* @stderr
%6 = load i8*, i8** %1
%7 = tail call i32 @fprintf(i32 %5, i8* getelementptr inbounds ([30 x i8], [30 x i8]* @.str, i64 0, i64 0), i8* %6)
br label %28
8: ; preds = %2
%9 = getelementptr inbounds i8*, i8** %1, i64 1
%10 = load i8*, i8** %9
%11 = load i32, i32* @O_RDWR
%12 = tail call i32 @open(i8* %10, i32 %11)
%13 = icmp eq i32 %12, -1
br i1 %13, label %14, label %16
14: ; preds = %8
%15 = tail call i32 @perror(i8* getelementptr inbounds ([5 x i8], [5 x i8]* @.str.1, i64 0, i64 0))
br label %28
16: ; preds = %8
%17 = getelementptr inbounds i8*, i8** %1, i64 2
%18 = load i8*, i8** %17
%19 = tail call i32 @atoi(i8* %18)
%20 = shl nsw i32 %19, 20
%21 = tail call i32 @printf(i8* getelementptr inbounds ([25 x i8], [25 x i8]* @.str.2, i64 0, i64 0), i32 %20)
%22 = tail call i64 @ftruncate(i32 %12, i32 %20)
%23 = icmp eq i64 %22, 0
br i1 %23, label %26, label %24
24: ; preds = %16
%25 = tail call i32 @perror(i8* getelementptr inbounds ([10 x i8], [10 x i8]* @.str.3, i64 0, i64 0))
br label %28
26: ; preds = %16
%27 = tail call i32 @close(i32 %12)
br label %28
28: ; preds = %14, %26, %24, %4
%29 = phi i32 [ -1, %4 ], [ -1, %14 ], [ -1, %24 ], [ 0, %26 ]
ret i32 %29
}