------- Comment #4 from lucier at math dot purdue dot edu 2009-04-27 15:11 ------- Subject: Re: 96% performance regression in floating point code; part of the problem started 2009/03/12-13
On Mon, 2009-04-27 at 08:16 +0000, ubizjak at gmail dot com wrote: > > > ------- Comment #2 from ubizjak at gmail dot com 2009-04-27 08:16 ------- > (In reply to comment #0) > > > (same .i file, same instructions for reproducing, same compiler options, > > same > > everything) > > I guess that this is direct.i compiled with -O1? > Yes, the compile flags are -Wall -W -Wno-unused -O1 -fno-math-errno -fschedule-insns2 -fno-trapping-math -fno-strict-aliasing -fwrapv -fomit-frame-pointer -fPIC -fno-common -mieee-fp > It is not clear from your report, if -O1 flag is problematic, -O2 code looks > good to me. Yes, the -O2 code looks good to me, too. I've used the above list of options (starting with -O1) on this code instead of -O2 because the above list (a) has generally given faster performance, and (b) has required much less compile time and memory to compile the C code generated by the Gambit Scheme->C compiler. I have not yet seen any evidence that -O2 generates better code (overall) than those set of options above. Brad -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39914
