#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*/ printf(char *, int);
int main() {
  int i = 0;
  while (i < 20) {
    printf("message from popen %d\n", i);
    i++;
  }
  return 0;
}


x86 assembly (clang, -O0):
<main>:
push   %rbp
mov    %rsp,%rbp
sub    $0x10,%rsp
movl   $0x0,-0x4(%rbp)
movl   $0x0,-0x8(%rbp)
cmpl   $0x14,-0x8(%rbp)
jge    114d <main+0x3d>
mov    -0x8(%rbp),%esi
lea    0xec6(%rip),%rdi
call   1030 <printf@plt>
mov    -0x8(%rbp),%eax
add    $0x1,%eax
mov    %eax,-0x8(%rbp)
jmp    1126 <main+0x16>
xor    %eax,%eax
add    $0x10,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<main>:
push   %rbx
lea    0xee8(%rip),%rbx
mov    %rbx,%rdi
xor    %esi,%esi
call   1030 <printf@plt>
mov    %rbx,%rdi
mov    $0x1,%esi
call   1030 <printf@plt>
mov    %rbx,%rdi
mov    $0x2,%esi
call   1030 <printf@plt>
mov    %rbx,%rdi
mov    $0x3,%esi
call   1030 <printf@plt>
mov    %rbx,%rdi
mov    $0x4,%esi
call   1030 <printf@plt>
mov    %rbx,%rdi
mov    $0x5,%esi
call   1030 <printf@plt>
mov    %rbx,%rdi
mov    $0x6,%esi
call   1030 <printf@plt>
mov    %rbx,%rdi
mov    $0x7,%esi
call   1030 <printf@plt>
mov    %rbx,%rdi
mov    $0x8,%esi
call   1030 <printf@plt>
mov    %rbx,%rdi
mov    $0x9,%esi
call   1030 <printf@plt>
mov    %rbx,%rdi
mov    $0xa,%esi
call   1030 <printf@plt>
mov    %rbx,%rdi
mov    $0xb,%esi
call   1030 <printf@plt>
mov    %rbx,%rdi
mov    $0xc,%esi
call   1030 <printf@plt>
mov    %rbx,%rdi
mov    $0xd,%esi
call   1030 <printf@plt>
mov    %rbx,%rdi
mov    $0xe,%esi
call   1030 <printf@plt>
mov    %rbx,%rdi
mov    $0xf,%esi
call   1030 <printf@plt>
mov    %rbx,%rdi
mov    $0x10,%esi
call   1030 <printf@plt>
mov    %rbx,%rdi
mov    $0x11,%esi
call   1030 <printf@plt>
mov    %rbx,%rdi
mov    $0x12,%esi
call   1030 <printf@plt>
mov    %rbx,%rdi
mov    $0x13,%esi
call   1030 <printf@plt>
xor    %eax,%eax
pop    %rbx
ret

LLVM IR (-O0):
@.str = [23 x i8] c"message from popen %d\0A\00"
define i32 @main() {
%1 = alloca i32
%2 = alloca i32
store i32 0, i32* %1
store i32 0, i32* %2
br label %3
3: ; preds = %6, %0
%4 = load i32, i32* %2
%5 = icmp slt i32 %4, 20
br i1 %5, label %6, label %11
6: ; preds = %3
%7 = load i32, i32* %2
%8 = call i32 @printf(i8* getelementptr inbounds ([23 x i8], [23 x i8]* @.str, i64 0, i64 0), i32 %7)
%9 = load i32, i32* %2
%10 = add nsw i32 %9, 1
store i32 %10, i32* %2
br label %3
11: ; preds = %3
ret i32 0
}

LLVM IR (-O2):
@.str = [23 x i8] c"message from popen %d\0A\00"
define i32 @main() {
%1 = tail call i32 @printf(i8* getelementptr inbounds ([23 x i8], [23 x i8]* @.str, i64 0, i64 0), i32 0)
%2 = tail call i32 @printf(i8* getelementptr inbounds ([23 x i8], [23 x i8]* @.str, i64 0, i64 0), i32 1)
%3 = tail call i32 @printf(i8* getelementptr inbounds ([23 x i8], [23 x i8]* @.str, i64 0, i64 0), i32 2)
%4 = tail call i32 @printf(i8* getelementptr inbounds ([23 x i8], [23 x i8]* @.str, i64 0, i64 0), i32 3)
%5 = tail call i32 @printf(i8* getelementptr inbounds ([23 x i8], [23 x i8]* @.str, i64 0, i64 0), i32 4)
%6 = tail call i32 @printf(i8* getelementptr inbounds ([23 x i8], [23 x i8]* @.str, i64 0, i64 0), i32 5)
%7 = tail call i32 @printf(i8* getelementptr inbounds ([23 x i8], [23 x i8]* @.str, i64 0, i64 0), i32 6)
%8 = tail call i32 @printf(i8* getelementptr inbounds ([23 x i8], [23 x i8]* @.str, i64 0, i64 0), i32 7)
%9 = tail call i32 @printf(i8* getelementptr inbounds ([23 x i8], [23 x i8]* @.str, i64 0, i64 0), i32 8)
%10 = tail call i32 @printf(i8* getelementptr inbounds ([23 x i8], [23 x i8]* @.str, i64 0, i64 0), i32 9)
%11 = tail call i32 @printf(i8* getelementptr inbounds ([23 x i8], [23 x i8]* @.str, i64 0, i64 0), i32 10)
%12 = tail call i32 @printf(i8* getelementptr inbounds ([23 x i8], [23 x i8]* @.str, i64 0, i64 0), i32 11)
%13 = tail call i32 @printf(i8* getelementptr inbounds ([23 x i8], [23 x i8]* @.str, i64 0, i64 0), i32 12)
%14 = tail call i32 @printf(i8* getelementptr inbounds ([23 x i8], [23 x i8]* @.str, i64 0, i64 0), i32 13)
%15 = tail call i32 @printf(i8* getelementptr inbounds ([23 x i8], [23 x i8]* @.str, i64 0, i64 0), i32 14)
%16 = tail call i32 @printf(i8* getelementptr inbounds ([23 x i8], [23 x i8]* @.str, i64 0, i64 0), i32 15)
%17 = tail call i32 @printf(i8* getelementptr inbounds ([23 x i8], [23 x i8]* @.str, i64 0, i64 0), i32 16)
%18 = tail call i32 @printf(i8* getelementptr inbounds ([23 x i8], [23 x i8]* @.str, i64 0, i64 0), i32 17)
%19 = tail call i32 @printf(i8* getelementptr inbounds ([23 x i8], [23 x i8]* @.str, i64 0, i64 0), i32 18)
%20 = tail call i32 @printf(i8* getelementptr inbounds ([23 x i8], [23 x i8]* @.str, i64 0, i64 0), i32 19)
ret i32 0
}