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From Apache Wiki <wikidi...@apache.org>
Subject [Harmony Wiki] Update of "Jitrino OPT/peephole" by Mikhail Fursov
Date Mon, 12 May 2008 09:20:58 GMT
Dear Wiki user,

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The following page has been changed by Mikhail Fursov:
http://wiki.apache.org/harmony/Jitrino_OPT/peephole

New page:
''' 'peephole' ''' Performs various architecture specific per-Inst optimizations.
[[BR]]
The transformation performs simple local (per-BB) or per-Inst optimizations
[[BR]][[BR]]
Some of them include:
[[BR]]
{{{
1) Inlined F2I conversion

2) A better instructions selection:
    Change 32bit immediate values to 8bit in ALU instructions
    MOVSS/MOVSD replaced with MOVQ
    MOVSS/MOVSD xmm, [memconst=0.] => PXOR xmm, xmm
}}}
[[BR]]
It's recommended to have 2 passes of peephole: 
[[BR]]the first one before a register allocator - to inline the conversions and provide more
opportunities for further optimization. 
[[BR]]And the second one - after the register allocator to improve the instructions selection.

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