Re: [PATCH, tree-dce]: DCE enh to handle dead calls (not pure)

[Xinliang David Li <davidxl at google dot com>]

Steven Bosscher wrote:
> OK, this is something we probably don't want to do when optimizing for
> size (i.e. at -Os).  You'll have to add code to disable this
> transformation if optimize_size is set (probably do it in opts.c, see
> what's done there for flag_tree_pre).


Good catch!

> > > Third, at least for my taste you have *way* too many gcc_asserts.
> > > They are not free, you know, and you are asserting trivial things and
> > > things that you have already asserted before.  For example, in the
> > > gen_conditions_for* functions you re-assert everything you already
> > > asserted in the check* functions. Please reconsider whether you really
> > > need all of them.  gcc_assert is not free and also doesn't improve the
> > > readability of the code...
> > Maybe we need to introduce a gcc_dbg_assert. Is it there already?
>
> There is nothing like that.  I don't think anyone really wants this either ;-)

It should be useful -- I am not sure why you and Richard are against 
over-asserting -- there is no such thing :)



> > Ah, this is something I like to change systematially in gcc in the future --
> > all high level transformations will emit info messages -- for performance
> > tuning/triaging reason
>
> Why?  What would that give you that the dumps and the statistics stuff
> do not give you already?

Dump file contains too many stuff that are not needed -- not suitable 
for auto tools. Besises, info messages/op report are also for users 
(just like warnings), so internal dump does not make sense.

thanks,

David


> Gr.
> Steven