Re: patch that caused part of the compile-time regression in PRopt/8361

[Andreas Jaeger <aj at suse dot de>]

Janis Johnson <janis187@us.ibm.com> writes:

> I've been sick for a couple of weeks without much brainpower, but
> enough to build compilers and run tests occasionally.  I'm trying to
> track down changes that increased compile times for generate.ii from
> PR 8361.  This particular test case occasionally causes ICEs and
> sometimes gets compiler errors, so it's not a good candiate for a
> binary search; also, I wanted to keep track of times for multiple
> optimizations.  There are some other jumps later that I'll continue to
> look into, but the first big one is caused by this patch:
>
> 2002-04-27  Kurt Garloff <garloff@suse.de>
>
>         * tree-inline.c (inlinable_function_p): Improve heuristics
>         by using a smoother function to cut down allowable inlinable size.
>         * param.def: Add parameters max-inline-insns-single,
>         max-inline-slope, min-inline-insns that determine the exact
>         shape of the above function.
>         * param.h: Likewise.

Which makes sense since that patch allowed inlining of more functions
than before, resulting in better optimized binaries.  

I fear we always have this kind of problem that with adding
optimizations or - as in this case - making optimizations more
aggressive, gcc might slow down. :-(

Andreas
-- 
 Andreas Jaeger
  SuSE Labs aj@suse.de
   private aj@arthur.inka.de
    http://www.suse.de/~aj