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RE: GCC mini-summit - compiling for a particular architecture
- From: Ben Elliston <bje at au1 dot ibm dot com>
- To: Dave Korn <dave dot korn at artimi dot com>
- Cc: "'Diego Novillo'" <dnovillo at redhat dot com>, "'Mark Mitchell'" <mark at codesourcery dot com>, "'Kaveh R. GHAZI'" <ghazi at caip dot rutgers dot edu>, "'Richard Earnshaw'" <rearnsha at arm dot com>, "'Steve Ellcey'" <sje at cup dot hp dot com>, aaw at google dot com, kenneth dot hoste at elis dot ugent dot be, gcc at gcc dot gnu dot org
- Date: Tue, 01 May 2007 14:15:33 +1000
- Subject: RE: GCC mini-summit - compiling for a particular architecture
- References: <200704202322.QAA29468@hpsje.cup.hp.com> <462BFE92.2030905@codesourcery.com> <1177322806.14160.12.camel@pc960.cambridge.arm.com> <462CCBCB.50805@codesourcery.com> <Pine.GSO.4.58.0704231304040.13493@caipclassic.rutgers.edu> <462CF363.3060802@codesourcery.com> <462CF5BB.1070108@redhat.com> <004401c785d4$f1b684a0$2e08a8c0@CAM.ARTIMI.COM>
On Mon, 2007-04-23 at 19:26 +0100, Dave Korn wrote:
> Has any of the Acovea research demonstrated whether there actually is any
> such thing as a "good default set of flags in all cases"? If the results
> obtained diverge significantly according to the nature/coding
> style/architecture/other uncontrolled variable factors of the application, we
> may be labouring under a false premise wrt. the entire idea, mightn't we?
My experimentation found that the sequences were highly dependent on the
input programs, as you might expect. Therefore, it would be quite hard
to choose a "good default set in all cases". In fact, you could argue
that this is totally contrary to the whole idea of iterative
compilation, which assumes that there is no good one default set and
you're better off searching.
Cheers, Ben
--
Ben Elliston <bje@au.ibm.com>
Australia Development Lab, IBM