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[Bug rtl-optimization/19097] [3.4/4.0/4.1 regression] Quadratic behavior with many sets for the same register in gcse CPROP
- From: "steven at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 16 Oct 2005 23:20:30 -0000
- Subject: [Bug rtl-optimization/19097] [3.4/4.0/4.1 regression] Quadratic behavior with many sets for the same register in gcse CPROP
- References: <bug-19097-7737@http.gcc.gnu.org/bugzilla/>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Comment #17 from steven at gcc dot gnu dot org 2005-10-16 23:20 -------
On AMD64, I now get the following timings:
-O1 -O2
3.3 (profilebootstrapped) 46.64 46.90
4.1 (checking=release) 72.82 156.43
In 4.1, the Big Spenders are "dominance frontiers" (41% usr)
and "tree operand scan" (also 41%) for -O1. For -O2 those two
also are big time black holes, and the 3 gcse.c CPROP passes
join them at the top of the profile ("dominance frontiers" 18%,
"tree operand scan" 18%, "CPROP 1" 17%, "CPROP 2" 9%, "bypass
jumps" 10%).
So this is still a regression from GCC 3.3.
--
steven at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
Known to fail|4.0.0 |4.0.0 4.1.0
Last reconfirmed|2005-10-16 22:35:50 |2005-10-16 23:20:30
date| |
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19097