Re: Compilation performance comparison of 3.5.0 and TreeSSA treeson MICO sources as requested in: [tree-ssa] Merge status 2004-05-03

[Karel Gardas <kgardas at objectsecurity dot com>]

On Tue, 4 May 2004, Andrew Pinski wrote:

>
> On May 4, 2004, at 17:13, Mike Stump wrote:
>
> > On Tuesday, May 4, 2004, at 01:50 PM, Karel Gardas wrote:
> >> MICO doesn't look good. I've compared todays source trees:
> >
> >> File		350-O0	TSSA-O0	Delta%	350-O2	TSSA-O2
> >
> >> Sum		523.2	649.36	-19.43	774.7	904.11	-14.31
> >>
> >> Conclusion: compile time regressions for both -O0 and -O2 compilation.
> >
> > Thanks.  While I'll happily take the 14% hit for optimized code, the
> > 20% drop for -O0 I want to bitch about.  Last time we lost 34% in one
> > tiny patch, we lost, and the work went in anyway.  That was almost ok,
> > as we just reverted the work that caused the regression in our tree.
> > However, we have no ability to `revert' treessa for -O0 to gain the
> > 20% back.
> >
> > I'd like ask people to see if there is anyway to get that back.  If
> > not all of it, part of it?
>
> Yes there is a way, it is called do some optimizations at -O0.  The
> problem with the tree-ssa,
> the RTL which is generated for an unoptimized run is just huge compared
> to what the mainline
> was/is.  Simple things like DCE will help a lot on the compile time and
> code size.

Hmm, do you think I should try -O1 test? I guess it will place somewhere
between 14-19% regression, but if you would like to see it, I will do it
ASAP.

Karel
--
Karel Gardas                  kgardas@objectsecurity.com
ObjectSecurity Ltd.           http://www.objectsecurity.com