[Bug tree-optimization/52523] New: Missing "uninitialized" warning in simple code

[andreac at unstable dot it]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52523

             Bug #: 52523
           Summary: Missing "uninitialized" warning in simple code
    Classification: Unclassified
           Product: gcc
           Version: 4.7.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
        AssignedTo: unassig...@gcc.gnu.org
        ReportedBy: andr...@unstable.it


Compiling this code:

#include <iostream>
int main()
{
  int x;
  std::cout << x;
  std::cin >> x;
}

with g++ -Wall uninitialized.cc
give no warning.

But compiling this code:

#include <iostream>
int main()
{
  int x;
  std::cout << x;
}

with g++ -Wall uninitialized.cc
gives:
uninitialized.cc: In function ‘int main()’:
uninitialized.cc:6:17: warning: ‘x’ is used uninitialized in this function
[-Wuninitialized

Tested also on version 4.6.1 and 4.6.2