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Posted to commits@harmony.apache.org by Apache Wiki <wi...@apache.org> on 2008/05/12 11:20:58 UTC
[Harmony Wiki] Update of "Jitrino OPT/peephole" by Mikhail Fursov
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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.