Date: Mon, 08 Oct 2007 19:53:37 -0700 From: LI Xin <delphij@delphij.net> To: Bruce Evans <brde@optusnet.com.au> Cc: d@delphij.net, freebsd-arch@freebsd.org Subject: Re: Why we optimize by time by default for < -O2 case? Message-ID: <470AED31.60201@delphij.net> In-Reply-To: <20071009122751.X54949@besplex.bde.org> References: <470ACEA1.3030309@delphij.net> <20071009122751.X54949@besplex.bde.org>
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[-- Attachment #1 --] Bruce Evans wrote: > On Mon, 8 Oct 2007, LI Xin wrote: > >> I wonder why we want to optimize by time by default and not by space by >> default for the system compiler, does the reasoning still hold true? > > -O means optimize for time if possible. > >> The commit log said: >> >> Modified files: >> contrib/gcc toplev.c >> Log: >> Clarify revision 1.14: >> Gcc 3.1's -O0 and -O1 actually optimized alignment for space, but we >> feel >> it should optimize alignment for time like Gcc 2.95 used to. >> Optimization >> for space should give 1-byte alignment on i386's, but doesn't quite. >> >> Revision Changes Path >> 1.15 +0 -0 src/contrib/gcc/toplev.c > > Without this change, -O pessimizes for time. Does this affect all platforms or is it i386 only, on the latest GCC version? Cheers, -- Xin LI <delphij@delphij.net> http://www.delphij.net/ FreeBSD - The Power to Serve! [-- Attachment #2 --] -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.7 (Darwin) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iD8DBQFHCu0yOfuToMruuMARCqq6AJ9kgt+/seMxXRUvLOos4Q/N2aRIXQCeI0A7 DvXzq5qtLgwhZQx1iG5Bnl0= =IXVY -----END PGP SIGNATURE-----home | help
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