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[Bug regression/39914] 96% performance regression in floating point code; part of the problem started 2009/03/12-13
- From: "lucier at math dot purdue dot edu" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 27 Apr 2009 15:35:33 -0000
- Subject: [Bug regression/39914] 96% performance regression in floating point code; part of the problem started 2009/03/12-13
- References: <bug-39914-271@http.gcc.gnu.org/bugzilla/>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Comment #7 from lucier at math dot purdue dot edu 2009-04-27 15:35 -------
Subject: Re: 96% performance regression in floating
point code; part of the problem started 2009/03/12-13
On Mon, 2009-04-27 at 15:32 +0000, lucier at math dot purdue dot edu
wrote:
> On Mon, 2009-04-27 at 15:26 +0000, pinskia at gcc dot gnu dot org wrote:
>
> > This is by design -O1 is way slower than -O2 now.
>
> I have seen no general discussion that -O1 should be destroyed as a
> useful compilation option.
Perhaps I should also point out that code generated by -O2 is not
generally much faster than before, so if you believe that -O1 is much
slower than -O2 now by design, it is only by making code generated by
-O1 much slower.
BTW, this code runs in 108 ms when compiled with gcc-4.2.4 with the
given options (including -O1).
Brad
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39914