On Wed, Oct 5, 2022 at 12:14 PM Aldy Hernandez <aldyh@redhat.com> wrote:

> However... I don't think I have the stomach to overhaul the allocators
> this late in the release.  For this release I may opt to put the
> nonzero mask back in a tree, but have it always be set.  The NULL ==
> -1 shortcut was very error prone.  The rest of my fixes in this patch
> still apply, as they keep better track of the masks, which we need.

Here is the patch reverting the nonzero mask to trees.

Unfortunately, having the mask always set caused a 10% regression in
VRP, so that's a no go.  I've gone back to keeping a NULL mask by
default that semantically means -1.  It's not as bad as I thought,
since the code is much cleaner now.  This is unfortunate, but a 10%
regression in VRP plus a 1.5% regression in overall compilation is
unacceptable.  On the plus side, this is temporary as we're moving
entirely to wide ints next release (with appropriate cache/allocator
changes).

I will commit after a final round of tests finishes.

Thanks.
Aldy