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Date: Mon, 18 Aug 2008 13:32:00 -0000
Subject: [Bug c/37148]  New: -Wunintialized fails in the face of conditional assignment.
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From: "thutt at vmware dot com" <gcc-bugzilla@gcc.gnu.org>
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Although I demonstrated this using 4.1.2 on my host, it probably affects
other versions as well.

As the following code shows:

    gcc -c -O1 -Wall -Werror uninitialized-warning.c

    extern void called_function(unsigned p);
    extern unsigned g;

    void
    f0(unsigned parm)
    {
       unsigned v;
       if (parm == 0) {
          v = 4;
       }
       called_function(v);
    }

    void
    f1(unsigned parm)
    {
       unsigned v;
       if (parm == 0) {
          v = 4;
       } else {
          g = 0;
       }
       called_function(v);
    }

    void
    f2(unsigned parm)
    {
       unsigned v;
       called_function(v);
    }

gcc does not produce the 'uninitialized' warning when the automatic
variable is conditionally assigned.

This gives a very bad false sense of security that the automatic
variables are indeed initialized.


-- 
           Summary: -Wunintialized fails in the face of conditional
                    assignment.
           Product: gcc
           Version: 4.1.2
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: thutt at vmware dot com


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37148