gcc flags for developers (Re: [PATCH] a little optimization of KJS GarbageCollector)

David Faure faure at kde.org
Fri Dec 2 13:07:44 GMT 2005

On Thursday 01 December 2005 17:51, Dirk Mueller wrote:
> On Thursday 01 December 2005 17:34, Martijn Klingens wrote:
> > Do I understand correctly that --enable-debug (without =full) gives the -O2
> > -fno-reorder-blocks -fno-schedule-insns -fno-inline that you mentioned?
> No, it gives you "-O2 -g" for historic reasons. 

Can we change the defaults so that reasonable/useful flags are being used then?

Problem is, I see two possibilities, for developers:
1) with debug but with -O0 so that gcc runs fast   (or does -O1 make gcc fast enough?)
2) with debug and with "-O2 -fno-reorder-blocks -fno-schedule-insns -fno-inline"
  so that the code runs faster and so that all warnings can be seen.

Does this mean it would make sense to have
 --enable-debug=fast for the first one,  and make --enable-debug select the second one?

or maybe
 --enable-debug=fast for the first one and --enable-debug=optimized for the second one,
to keep the current --enable-debug as -O2 -g? Although I don't see any point in
leaving things unchanged 'for historical reasons' if everyone agrees that it's wrong that way.

Not everyone is a gcc expert, we should select the right flags so that developers
don't have to care about all this.

David Faure, faure at kde.org, sponsored by Trolltech to work on KDE,
Konqueror (http://www.konqueror.org), and KOffice (http://www.koffice.org).

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