Article View: comp.arch
Article #21328Re: Register usage
From: Andrew Klossner
Date: Wed, 17 May 1989 20:06
Date: Wed, 17 May 1989 20:06
21 lines
1170 bytes
1170 bytes
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"Larger register sets pay you back when you do dataflow
analysis and allocate registers over larger spans of code than
C expression statements ... If you only have a handful of
registers, though, you might as well keep it simple."
Dataflow analysis is good for more than register allocation, and can be
a win on a register-starved machine. For example, when compiling this
code (which swaps "x" and "y"):
temp := x;
x := y;
y := temp;
if dataflow analysis tells you that "temp" is dead after this fragment,
you can avoid a store operation, and you've won even if you have only
two registers.
-=- Andrew Klossner (uunet!tektronix!orca!frip!andrew) [UUCP]
(andrew%frip.wv.tek.com@relay.cs.net) [ARPA]
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Path: arc1-ca.pugleaf.net!utzoo!attcan!uunet!tektronix!orca!frip!andrew From: andrew@frip.WV.TEK.COM (Andrew Klossner) Newsgroups: comp.arch Subject: Re: Register usage Message-ID: <3354@orca.WV.TEK.COM> Date: 17 May 89 20:06:38 GMT References: <921@aber-cs.UUCP> <16052@bellcore.bellcore.com> Sender: nobody@orca.WV.TEK.COM Distribution: eunet,world Organization: Tektronix, Wilsonville, Oregon Lines: 21