GhcLibHcOpts: -O or -O2?

Joachim Breitner mail at joachim-breitner.de
Tue Jul 15 22:09:13 UTC 2014


Hi,

I found that some performance tests cases fail in some setting, and not
in another, and after a while I found the cause: 
The default settings (i.e. no mk/build.mk) have GhcLibHcOpts=-O2, while
most development profiles (e.g. devel2) _and the validate settings_ have
GhcLibHcOpts=-O1.

It doesn’t make a lot of sense to have performance tests cases without
fixing this parameter. And I think we really should be validating the
settings that we actually used in the final build that we release.

Hence three questions:

 1. Are the default settings really the settings used when producing the
    final build?
 2. Do we want to use GhcLibHcOpts=-O2 or GhcLibHcOpts=-O for releases?
 3. Once 2. is answered, may I change the validate settings to that 
    value, and update the performance tests to expect the number
    produced with that value?

(This was first observed in 
https://ghc.haskell.org/trac/ghc/ticket/9315#comment:5 but I wanted to
the wider audience of the mailing list for such a design decision.)

Thanks,
Joachim
-- 
Joachim Breitner
  e-Mail: mail at joachim-breitner.de
  Homepage: http://www.joachim-breitner.de
  Jabber-ID: nomeata at joachim-breitner.de

-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 819 bytes
Desc: This is a digitally signed message part
URL: <http://www.haskell.org/pipermail/ghc-devs/attachments/20140716/10d48016/attachment.sig>


More information about the ghc-devs mailing list