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[Bug tree-optimization/33604] [4.3 Regression] Revision 119502 causes significantly slower results with 4.3 compared to 4.2
- From: "bonzini at gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 7 Nov 2007 16:26:32 -0000
- Subject: [Bug tree-optimization/33604] [4.3 Regression] Revision 119502 causes significantly slower results with 4.3 compared to 4.2
- References: <bug-33604-15171@http.gcc.gnu.org/bugzilla/>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Comment #18 from bonzini at gnu dot org 2007-11-07 16:26 -------
Created an attachment (id=14498)
--> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=14498&action=view)
never say minimal!
So this is a testcase constructed from scratch. 4.3 is 4.5x slower (0.8s vs.
0.18s). Furthermore, if you "#define const", the performance pitfall goes
away.
For whoever wants to work on this, I would double check with the previous
minimal testcase, but this has the same symptoms (no SRA of the Ref instances)
and is much much smaller, so it is more suited to go in GCC's testsuite.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=33604