Spurious C++ compiler warning

[Michael Haggerty <mhagger at blizzard dot harvard dot edu>]

Hi,

I get a spurious warning from egcs 1.1a.  I don't see how `double x'
could be thought to be uninitialized in function f.  See the following
transcript for details.

======================================================================
$ uname -a
OSF1 tsunami.harvard.edu V4.0 564 alpha
$ e++ -v
Reading specs from /usr/local/egcs-1.1a/lib/gcc-lib/alpha-dec-osf4.0b/egcs-2.91.57/specs
gcc version egcs-2.91.57 19980901 (egcs-1.1 release)
$ cat bugtestii.cc
struct A
{
    virtual ~A();
};

struct B
{
    virtual ~B();
};

struct C
{
    int g(const B &);
};

struct D : public A
{
    struct E : public B {};
};


double f()
{
    D d;
    C c;

    double x = 0.0;

    do {
    } while (c.g(D::E()));

    return x;
}

$ e++ -W -O2 -c bugtestii.cc
bugtestii.cc: In function `double f()':
bugtestii.cc:27: warning: `double x' might be used uninitialized in this function
$ 
======================================================================

My compiler was built with the following commands (unpatched source):

======================================================================
# made directory ~/download/egcs-1.1a-compilation and changed to it.
CC=ecc nice -2 ../egcs-1.1a/configure --prefix=/usr/common/egcs-1.1a --exec-prefix=/usr/local/egcs-1.1a --enable-shared
nice -2 make CFLAGS='-O' LIBCFLAGS='-g -O2' LIBCXXFLAGS='-g -O2 -fno-implicit-templates' bootstrap
sudo nice -2 make install
ln -s /usr/local/egcs-1.1a/bin/c++ /usr/local/bin/e++
======================================================================

I hope this helps.

Michael

--
Michael Haggerty
mhagger@blizzard.harvard.edu