Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10 5/3/83; site umcp-cs.UUCP Path: utzoo!watmath!clyde!floyd!harpo!seismo!rlgvax!cvl!umcp-cs!chris From: chris@umcp-cs.UUCP Newsgroups: net.lang.c Subject: Re: more on C optimization Message-ID: <5927@umcp-cs.UUCP> Date: Thu, 15-Mar-84 01:17:34 EST Article-I.D.: umcp-cs.5927 Posted: Thu Mar 15 01:17:34 1984 Date-Received: Fri, 16-Mar-84 00:28:16 EST References: <86@eneevax.UUCP> Organization: Univ. of Maryland, Computer Science Dept. Lines: 23 All right, how come no one has replied yet??? I posted something a while ago about something /lib/c2 did that was "neat", namely, change movl $7,r11 ... bicl3 $-256,r11,r1 into movl $7,r11 ... extzv $0,r11,r11,r1 # look closely now (instead of "extzv $0,$7,r11,r1"). If you just think for a minute, the "extzv" is unnecessary in the first place! If c2 does limited flow analysis to watch over register contents, how come it doesn't eliminate instructions that are effectively no-ops? (That's a rhetorical question, by the way.) -- In-Real-Life: Chris Torek, Univ of MD Comp Sci UUCP: {seismo,allegra,brl-bmd}!umcp-cs!chris CSNet: chris@umcp-cs ARPA: chris.umcp-cs@CSNet-Relay