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Re: Loop unrolling





  > As is stands now, deleting empty loops is a very desirable *feature*,
  > especially for higher-level languages like C++ and Java which may just
  > generate loops that the programmer doesn't see.  If anything, we need
  > to expand the detection and deletion of empty loops.  A couple of us
  > embarked on this exercise for a couple of weeks last summer, but the
  > lack of register lifetime information in the loop optimization pass
  > bit us badly.  Maybe its time to resurrect this old code and make it
  > work?
If you can provide source examples which show C++ & Java creating empty
loops behind the programmer's back it would go a long way to convincing
everyone that eliminating empty loops is a good idea.

It's also been suggested that having register lifetime information would
allow us to fix the infamous x86 strength reduction bug and re-enable
strength reduction.

jeff


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