optimization/6007: cfg cleanup tremendous performance hog with -O1

Brad Lucier lucier@math.purdue.edu
Fri Mar 29 14:00:00 GMT 2002

> Hi, here is patch I made as a test.  It simply disables crossjumping
> if there is moer than 100 outgoing edges.  Unfortunately I can't benchmark
> your testcase as my machine runs out of space before getting there.  Can you
> check if this solves your problem?  If so, I will prepare more polished
> version of this patch.

You patch did help substantially, but not sufficiently.  I just
finished a run on denoise3.i with pre-patch cc1; the time for cfg cleanup
before your patch is

 cfg cleanup           :9486.98 (95%) usr   0.00 ( 0%) sys9510.00 (95%) wall

the time after your patch is

 cfg cleanup           :3156.77 (87%) usr   0.04 ( 0%) sys3193.00 (86%) wall

The times for other passes were substantially the same with and without
the patch.


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