[PATCH 03/10] tree-object-size: Use tree instead of HOST_WIDE_INT

Siddhesh Poyarekar siddhesh@gotplt.org
Tue Nov 23 13:33:17 GMT 2021


On 11/23/21 17:28, Jakub Jelinek wrote:
> On Mon, Nov 22, 2021 at 01:32:22PM +0100, Jakub Jelinek via Gcc-patches wrote:
>> On Mon, Nov 22, 2021 at 06:01:08PM +0530, Siddhesh Poyarekar wrote:
>>> On 11/22/21 17:30, Siddhesh Poyarekar wrote:
>>>> So I've got patch 10/10, which handles dynamic (and consequently
>>>> negative) offsets.  It basically computes a "whole size", which then
>>>> gives the extent to which a negative offset is valid, making the
>>>> estimates a bit more precise.  I didn't do it for static object sizes
>>>> because I didn't have time then, but I could add a patch 11/10 if the
>>>> idea sounds OK to you.
>>>
>>> ... or alternatively, I could bring the whole size idea into this tree
>>> conversion patch so that it handles all kinds of offsets.  That might even
>>> eliminate patch 10/10.  What would you prefer?
>>
>> Into this patch.
> 
> BTW, seems the current behavior is to punt on those "negative" values,
> we trigger
>    if (offset >= offset_limit)
> case for it and return unknown.

The current behaviour is actually inconsistent; for SSA names it punts 
for sizes greater than offset limit and for addr_expr it ends up with 
larger sizes.

Siddhesh


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