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Re: [PATCH, PR 51600] IPA-CP workaround for negative size cloning estimates
On Wed, Dec 21, 2011 at 5:29 PM, Jan Hubicka <hubicka@ucw.cz> wrote:
>> Hi,
>>
>> given that we already have a workaround for zero size increase
>> estimates from estimate_ipcp_clone_size_and_time, I see little reason
>> not to extend it to negative values too, 0 is really just as bad as -2
>> that we are getting in the testcase. ?Hopefully this will allow peple
>> who hit this bug proceed with their testing.
>>
>> Bootstrapped and tested on x86-64-linux with no regressions.
>> OK for trunk?
>
> Hmm, so the size value is not negative because estimate_ipcp_clone_size_and_time
> would return 0 or negative value but because of
> ?size -= stats.n_calls * removable_params_cost
> (i.e. the callee function is so small that the program will really shrink because
> of reduced call overhead)?
That doesn't make sense - is the 'removable_params_cost' maybe not
in-line with what estimate_num_insns computes for the param part
of the call cost?
> In that case I guess the patch is OK, but please update the comment,
> in current form it realy is misleading - i.e. we do not estimate functions
> to have size of 0.
>
> Honza