[LLVMdev] complex branching generation

Dale Johannesen dalej at apple.com
Wed Oct 1 14:14:14 PDT 2008

On Oct 1, 2008, at 1:44 PMPDT, Bill Wendling wrote:
> -Os runs these passes more than -O2: -domfrontier -lcssa -loop-unroll

Are you sure?  That looks wrong; I don't think -Os should be doing  
loop unrolling.  (Perhaps it should be on at -O2, as well.  gcc's loop  
unrolling is not turned on by -Oanything, you have to use the switch  
explicitly, and that's how it's documented.  But I think that's  
because its loop unrolling heuristics aren't all that good, and I  
don't think we should feel constrained to follow this if ours shows a  
win at -O2.)

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