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[Bug tree-optimization/53726] [4.8 Regression] aes test performance drop for eembc_2_0_peak_32
- From: "rguenth at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Wed, 20 Jun 2012 12:31:22 +0000
- Subject: [Bug tree-optimization/53726] [4.8 Regression] aes test performance drop for eembc_2_0_peak_32
- Auto-submitted: auto-generated
- References: <bug-53726-4@http.gcc.gnu.org/bugzilla/>
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53726
--- Comment #6 from Richard Guenther <rguenth at gcc dot gnu.org> 2012-06-20 12:31:22 UTC ---
Btw, I cannot reproduce the slowdown on 64bit and the 32bit memcpy in glibc
simply does a rep movsb; for any size lower than 20 bytes ... but as I have
been told rep movsb; setup cost is prohibitively high on most Intel CPUs ...
Thus, I suppose you should look at improving the memcpy implementation for
small sizes on 32bits.