Problem with ssa optimization making an uninitialized variable

[Richard Kenner]

Look at ada/g-socket.adb, line 1083.  Note that V4 has its address taken, so
that reference is not an unitialized reference.  But I get a warning about it.

If I look at .t25.phiop1, I see:

<L81>:;
  v4.1099_135 = v4;
  v4.1105_136 = (natural___XDLU_0__2147483647)v4.1099_135;
  opt.size = v4.1105_136;

That looks right.

But in .t26.alias, I have:

<L81>:;
  v4.1099_135 = v4_131;
  v4.1105_136 = (natural___XDLU_0__2147483647)v4.1099_135;
  opt.size = v4.1105_136;

That looks wrong with v4_131 undefined.

Where should I look to see what's going on here?