[Bug middle-end/29256] [4.2 regression] loop unrolling performance regression

pinskia at gcc dot gnu dot org gcc-bugzilla@gcc.gnu.org
Thu Sep 28 13:47:00 GMT 2006



------- Comment #6 from pinskia at gcc dot gnu dot org  2006-09-28 13:47 -------
(In reply to comment #4)
> On x86_64 4.2 decides to unroll 9 times while on 4.1 it unrolls 8 times.  This
> is
> a code-size regression, but other than that?  The 4.2 version runs slightly
> faster than the 4.1 version, though the difference may be in the noise.

No, no, no, I and Edmar are not complaining about how many times it unrolled
but the use of index addressing mode instead of offset addressing mode for the
stores and the extra adds.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29256



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