From: cinap_lenrek@felloff.net
To: 9fans@9fans.net
Subject: [9fans] 6c CMP reg, $0 optimization
Date: Sat, 29 Mar 2014 04:56:39 +0100 [thread overview]
Message-ID: <ce644c9a44755617919b40d299798f4a@felloff.net> (raw)
i changed the compiler to remove unneeded compare with
zero instructions when the previous instruction already
sets the zero flag in the peephole optimizaiton pass.
http://felloff.net/usr/cinap_lenrek/6cpeep.diff
this removes compares for zero/non zero tests only.
it only looks at the previous non-nop instruction
to see if it sets our compare value register.
it seems to work fine so far. our pc64 kernel got
arround 8K smaller, ghostscript got 5K smaller.
i'm not a compiler expert tho, so i'd like to hear if
there are any issues with this approach or if there are
better ways to do this.
--
cinap
next reply other threads:[~2014-03-29 3:56 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-03-29 3:56 cinap_lenrek [this message]
2014-03-29 4:00 ` erik quanstrom
2014-03-29 4:06 ` cinap_lenrek
2014-03-29 4:12 ` erik quanstrom
2014-03-29 4:12 ` Charles Forsyth
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