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List:       sbcl-devel
Subject:    Re: [Sbcl-devel] RFC: optimizing inline fixnum addition with
From:       Vitaly Mayatskikh <v.mayatskih () gmail ! com>
Date:       2010-10-14 12:45:08
Message-ID: 87iq15ymcr.wl%v.mayatskih () gmail ! com
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At Tue, 5 Oct 2010 10:42:41 -0400, Nathan Froyd wrote:

> 3) The JO to *ELSEWHERE* is a little bulky.  We could slim the code down to:
> 
>   ADD X, Y
>   JNO L0
>   CALL FIXUP-FIXNUM+OVERFLOW-IN-X
> L0:
> 
> but that does not help the branch predictor.

SBCL can help it manually by placing predicting hint (0x3e - branch is
taken, 0x2e - not taken).

-- 
wbr, Vitaly

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