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[Bug rtl-optimization/34826] New: branch probability is not reserved with do-loop optimization
- From: "eres at il dot ibm dot com" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 17 Jan 2008 07:18:30 -0000
- Subject: [Bug rtl-optimization/34826] New: branch probability is not reserved with do-loop optimization
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
Running the attached testcase with trunk r131577 on SPU
with -dm -fmodulo-sched -O2 flags (which enables also do-loop optimization)
demonstartes the fact that the branch probability is not reserved with do-loop
optimization.
This causes a major preformance regression (of about 40%) when tested with some
similar benchmark as there is no hardware branch prediction on SPU.
--
Summary: branch probability is not reserved with do-loop
optimization
Product: gcc
Version: 4.3.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: rtl-optimization
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: eres at il dot ibm dot com
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34826