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[Bug tree-optimization/24123] [4.1 Regression] Massive performance regression for -ffast-math due to the recip tree pass
- From: "bonzini at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 30 Sep 2005 13:17:00 -0000
- Subject: [Bug tree-optimization/24123] [4.1 Regression] Massive performance regression for -ffast-math due to the recip tree pass
- References: <20050929140549.24123.uros@kss-loka.si>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Additional Comments From bonzini at gcc dot gnu dot org 2005-09-30 13:16 -------
hum, strange. i don't get absolutely any difference before and after recip on
sbisect (and the family of functions it invokes, i.e. polyeval, regula_falsa and
numchanges) in polysolv.cpp from povray 3.6.1. and indeed by browsing at the
source code, i saw no optimization opportunities there.
uros, can you do the same test? (i.e. compile polysolv.cpp with all your options
+ -fdump-tree-all, and then "diff -u polysolv.cpp.*.loopdone polysolv.cpp.*.recip").
tnx,
Paolo
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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24123