[3.4 - BIB] New loop optimizer, part 1

[Roger Sayle]

Hi Zdenek,

This can probably be addressed in a follow-up patch but:

> +   /* The dominator of cont.  */
> +   rtx cont_dominator;
> +

this field was removed from "struct loop" a while back, but it
looks like its magically reappeared in your new "cfgloop.h".

Do you have any performance figures for your new loop optimizer?

You also mention that all four patches were bootstrapped on i686,
but are there any changes in the testsuite?  There are numerous
PRs for bugs in the old loop optimizer, so I'd hope that atleast
some of them might be fixed by a new implementation.

Roger
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