[Bug tree-optimization/60766] New: Wrong optimization with -O2

[mirzayanovmr at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60766

            Bug ID: 60766
           Summary: Wrong optimization with -O2
           Product: gcc
           Version: 4.8.2
            Status: UNCONFIRMED
          Severity: major
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: mirzayanovmr at gmail dot com

Created attachment 32546
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=32546&action=edit
Compile with -O2 and input 9

Compile the following code with -O2:

~~~~~
#include <cstdlib>
#include <iostream>
#include <cstdio>

using namespace std;

int main() {
    int n;
    cin >> n;

    for (int x = 0; x <= n; x++) {
        if (n == x + (x + 1) + (x + 2)) {
            cout << x + 2 << " " << x + 1 << " " << x << endl;
            exit(0);
        }
    }
    cout << -1 << endl;
    return 0;
}
~~~~~

Start binary and enter 9

It will print "-1", but expected output is "4 3 2".