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Re: [PATCH] pr70890, r235660 miscompiles stage2

On 05/03/2016 03:24 PM, Alan Modra wrote:


Err, is loop depth accurate in 254r.sched1?

In the ira dump, I see them all at loop depth 1.
So I expect that DF doesn't see the death because we're in a loop.


looks like we should have a death note? I could see how such a move would
create a new death if the def was moved into a loop from outside.


We won't move into a loop from outside.
       if (bb_loop_depth (use_bb) > bb_loop_depth (def_bb))
	continue;


I know, I was just uncertain whether that information is actually accurate.
If that is all ok and we just have a really odd cfg, then your patch is ok with a better comment as to which situations can cause the problem. 


Bernd
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