Re: ptrlist-iterator performance on one wine source file

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Sat, Jul 29, 2017 at 6:25 PM, Christopher Li <sparse@xxxxxxxxxxx> wrote:
> On Sat, Jul 29, 2017 at 12:04 PM, Luc Van Oostenryck
> <luc.vanoostenryck@xxxxxxxxx> wrote:
>>
>> You can't do that once cycles are involved. You need something
>> like the marking algorithm used by kill_unreachable_bbs() for that.
>> And it was such a  cycle that created the problem with the false
>> "crazy programmer" warning.
>
> No I don't think so. The find dominator already taking the cycles into
> account. By definition if X dominate Y, means every execution flow
> from entry point to Y will need to go through X. If X was not reachable,
> nor does Y. It does not change where the block get deleted. It just don't
> not need to do the marking algorithm. That is the point of dominator tree.

OK, I misread and misunderstood that you was talking about  the
dominator *tree*.

The real problem with such a tree is that you need to maintain it as
it potentially changes each time there is a change in the CFG.
And of course, building this tree is not linear (in the number of BBs)
while finding the dead BBs is linear.

-- Luc
--
To unsubscribe from this list: send the line "unsubscribe linux-sparse" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html



[Index of Archives]     [Newbies FAQ]     [LKML]     [IETF Annouce]     [DCCP]     [Netdev]     [Networking]     [Security]     [Bugtraq]     [Yosemite]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Linux SCSI]     [Trinity Fuzzer Tool]

  Powered by Linux