Re: kernel vm question

From: Dag-Erling Smørgrav (des_at_des.no)
Date: 01/28/05

  • Next message: Seán C. Farley: "initiate_write_inodeblock_ufs2() panic in 5-STABLE" 
    To: Jacques Fourie <jf@trispen.com>
Date: Fri, 28 Jan 2005 13:11:20 +0100

    des@des.no (Dag-Erling Smørgrav) writes:
    > David Schultz <das@FreeBSD.ORG> writes:
    > > When the line is there, the compiler is probably smart enough to
    > > realize that 'x=y; y=x' is (usually) a no-op, so it optimizes away
    > > both statements.
    > Wrong. The compiler is free to optimize away the second statement
    > provided that neither x nor y is declared volatile, but it cannot
    > optimize away the first statement.

    I should add: unless it can determine with absolute certainty that x
    is not referenced later.

    DES 

    -- 
Dag-Erling Smørgrav - des@des.no
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