Article View: comp.lang.misc
Article #5661Re: Query re optimising hcrs
From: Barry Margolin
Date: Sat, 30 Jul 1988 10:14
Date: Sat, 30 Jul 1988 10:14
25 lines
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1346 bytes
In article <3678@hcr.UUCP> jim@hcr.UUCP (Jim Sullivan) writes:
]In article <24414@think.UUCP> barmar@kulla.think.com.UUCP (Barry Margolin) writes:
]>Under this assumption, the transformation of
]> if <complex-expr> & <simple-expr>
]> then <result>
]>into
]> if <simple-expr>
]> then if <complex-expr>
]> then <result>
]>is reasonable.
]Actually, it isn't.... For example,
] if( a && b )
That is why MY example used "&", not "&&". We should all know that
when the language semantics specify a particular order of evaluation
it is not reasonable for an optimizing compiler to change it. The
discussion presupposed certain optimizations that are valid, and the
question was whether they are reasonable.
Barry Margolin
Thinking Machines Corp.
barmar@think.com
{uunet,harvard}!think!barmar
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Path: arc1-ca.pugleaf.net!utzoo!utgpu!water!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!rutgers!gatech!bloom-beacon!think!barmar From: barmar@think.COM (Barry Margolin) Newsgroups: comp.lang.misc Subject: Re: Query re optimising hcrs Message-ID: <24655@think.UUCP> Date: 30 Jul 88 10:14:29 GMT References: <561@etive.ed.ac.uk> <24414@think.UUCP> <3678@hcr.UUCP> Sender: usenet@think.UUCP Reply-To: barmar@kulla.think.com.UUCP (Barry Margolin) Organization: Thinking Machines Corporation, Cambridge, MA Lines: 25