Re: [tree-ssa] New regressions as of 2003-11-04

[Zdenek Dvorak <rakdver at atrey dot karlin dot mff dot cuni dot cz>]

Hello,

>  >>  >Concerning compile time -- there is nothing much to worry about, since
>  >>  >no transformation done by remove_useless_stmts_and_vars does anything
>  >>  >important with it.
>  >> My timings showed quite the opposite.
>  >
>  >Huh??? Timings of what?
> When I wrote remove_useless_stmts_and_vars I actually took the time to measure
> how it impacted compile-time performance.

you wrote it working on cfg? Otherwise I don't see how the timing is
relevant.  Anyway, my patch does not change cfg at all and the only
thing it does is a simple pass over all statements, so I don't see a
potential for it to be slow.

>  >>  >http://gcc.gnu.org/ml/gcc-patches/2003-11/msg00388.html.
>  >> And have you compared the timings before and after with your patch?
>  >> 
>  >> Have you verified that it covers all the cases that we were previously
>  >> handling (by looking at the dumps before/after)
>  >
>  >I have just copied everything that currently indeed does anything to the
>  >function, so it should.
> I want you to sit down and look at the dumps.  Just saying you copied
> everything isn't sufficient since you don't actually know if it's working.

You really believe I did not look at them, or what?  Sorry that I did
not state it explicitly, but I assume we are both inteligent people who
don't need to say every self-evident thing.

> You didn't do this kind of analysis with the COND_EXPR lowering code
> for example, and if you had done so you probably would have noticed that
> were were missing many transformations that were working with the old
> COND_EXPR code, but were not working with the new COND_EXPR code.

Yes I did, and I stated it clearly when I posted the patch. And since
they were mostly useless, I ignored it.

Zdenek