In .general_ci_points_4 function of 177.mesa, for example, the following
preheader block is created by the loop simplify pass:

no_exit.0.preheader:
%iy.2.ph = phi int [ 0, %cond_true.0 ], [ 0, %cond_true.1 ], [ 0, %cond_false.1
]             
%ix.4.ph = phi int [ 0, %cond_true.0 ], [ 0, %cond_true.1 ], [ 0, %cond_false.1
]             
%y1.1.ph = phi int [ 0, %cond_true.0 ], [ 0, %cond_true.1 ], [ 0, %cond_false.1
]             
%y0.1.ph = phi int [ 0, %cond_true.0 ], [ 0, %cond_true.1 ], [ 0, %cond_false.1
]             
%x1.1.ph = phi int [ 0, %cond_true.0 ], [ 0, %cond_true.1 ], [ 0, %cond_false.1
]             
%x0.1.ph = phi int [ 0, %cond_true.0 ], [ 0, %cond_true.1 ], [ 0, %cond_false.1
]             
%z.0.ph = phi int [ 0, %cond_true.0 ], [ 0, %cond_true.1 ], [ 0, %cond_false.1 ]
             
%y.0.ph = phi int [ 0, %cond_true.0 ], [ 0, %cond_true.1 ], [ 0, %cond_false.1 ]
             
%x.0.ph = phi int [ 0, %cond_true.0 ], [ 0, %cond_true.1 ], [ 0, %cond_false.1 ]
             

This is a common occurance, so the loop simplify pass should try a bit harder to
clean things up for subsequent loop optimization passes.

-Chris

This should be easy to fix, I just didn't want to forget about it.

-Chris

This problem is fixed like so:
http://mail.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20031215/010354.html

Many fewer PHI nodes are created and inserted.  I feel much better now.  :)

-Chris