Re: [vta, vta4.4] merged with trunk and 4.4 @149247, updated VTA patchset

[Alexandre Oliva <aoliva at redhat dot com>]

On Jul 10, 2009, Richard Guenther <richard.guenther@gmail.com> wrote:

> On Fri, Jul 10, 2009 at 8:53 PM, Alexandre Oliva<aoliva@redhat.com> wrote:
>> On Jul Â8, 2009, Richard Guenther <richard.guenther@gmail.com> wrote:
>> 
>>>> FWIW, adding an inform() in the beginning of the block containing the
>>>> loop above, I get 26367 hits during stage3+libs, and another 2700+ hits
>>>> in gcc/testsuite/*[^0-9]/*.log
>> 
>>> Well, that is bigger than zero. ÂBut no hint if it is significant or not.
>>> What is the number of hits for the case the bbs are different?
>> 
>> I have no idea, and I don't see why that matters. ÂIf there are 30K
>> cases in which, with very a little effort, we can avoid dropping debug
>> information on the floor, we should do it.

> Well, "very little effort" is exactly what I question given the linear scan
> of the BB.  Which is why I asked for numbers.

I was speaking of very little programming effort.  Current performance
measurements of the low overhead brought in by maintaining VTA notes up
to date shows it's pretty low.  If it ever proves to be a problem, it
won't be hard to compute stmt uids and use them instead.

-- 
Alexandre Oliva, freedom fighter    http://FSFLA.org/~lxoliva/
You must be the change you wish to see in the world. -- Gandhi
Be Free! -- http://FSFLA.org/   FSF Latin America board member
Free Software Evangelist      Red Hat Brazil Compiler Engineer