Re: [PATCH] Add auto-resizing capability to irange's [PR109695]

[Aldy Hernandez <aldyh@redhat.com>]

On 5/15/23 12:42, Jakub Jelinek wrote:
> On Mon, May 15, 2023 at 12:35:23PM +0200, Aldy Hernandez wrote:
>> gcc/ChangeLog:
>>
>> 	PR tree-optimization/109695
>> 	* value-range.cc (irange::operator=): Resize range.
>> 	(irange::union_): Same.
>> 	(irange::intersect): Same.
>> 	(irange::invert): Same.
>> 	(int_range_max): Default to 3 sub-ranges and resize as needed.
>> 	* value-range.h (irange::maybe_resize): New.
>> 	(~int_range): New.
>> 	(int_range::int_range): Adjust for resizing.
>> 	(int_range::operator=): Same.
> 
> LGTM.
> 
> One question is if we shouldn't do it for GCC13/GCC12 as well, perhaps
> changing it to some larger number than 3 when the members aren't wide_ints
> in there but just trees.  Sure, in 13/12 the problem is 10x less severe
> than in current trunk, but still we have some cases where we run out of
> stack because of it on some hosts.

Sure, but that would require messing around with the gt_* GTY functions, 
and making sure we're allocating the trees from a sensible place, etc 
etc.  I'm less confident in my ability to mess with GTY stuff this late 
in the game.

Thoughts?
Aldy