Date: Tue, 25 May 1999 12:35:12 -0400 (EDT) From: Garrett Wollman <wollman@khavrinen.lcs.mit.edu> To: current@freebsd.org Subject: More compiler option comparisons Message-ID: <199905251635.MAA11353@khavrinen.lcs.mit.edu>
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Just for completeness, I did one final run of HINT with just `-O' specified (our usual default). `-O' results in significantly better integer performance than `-O4'. (Floating-point performance is just the opposite.) This suggests that compiling the world with `-O' levels higher than one is probably a bad idea. (The generated assembly is identical from `-O2' to `-O4'.) The `-O2' code appears to be less efficient at register allocation; about twice as much stack temporary space is required. For the graph, see <http://bostonradio.org/wollman/O4-is-bad.ps>. -GAWollman -- Garrett A. Wollman | O Siem / We are all family / O Siem / We're all the same wollman@lcs.mit.edu | O Siem / The fires of freedom Opinions not those of| Dance in the burning flame MIT, LCS, CRS, or NSA| - Susan Aglukark and Chad Irschick To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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