[Bug c++/35117] Vectorization on power PC

["eyal at geomage dot com" <gcc-bugzilla at gcc dot gnu dot org>]

------- Comment #2 from eyal at geomage dot com  2008-02-07 10:36 -------
Yes the loop is vectorized. What do you mean by memory bound? dont you think
that vectorization can help here? I see around 20% performance gain in the real
application.

Bellow is the compiler output:
Eyal.cpp:34: note: dependence distance  = 0.
Eyal.cpp:34: note: accesses have the same alignment.
Eyal.cpp:34: note: dependence distance modulo vf == 0 between *D.22353_81 and
*D.22353_81
Eyal.cpp:34: note: versioning for alias required: can't determine dependence
between *D.22353_81 and *D.22365_101
Eyal.cpp:34: note: mark for run-time aliasing test between *D.22353_81 and
*D.22365_101
Eyal.cpp:34: note: versioning for alias required: can't determine dependence
between *D.22355_85 and *D.22353_81
Eyal.cpp:34: note: mark for run-time aliasing test between *D.22355_85 and
*D.22353_81
Eyal.cpp:34: note: versioning for alias required: can't determine dependence
between *D.22355_85 and *D.22365_101
Eyal.cpp:34: note: mark for run-time aliasing test between *D.22355_85 and
*D.22365_101
Eyal.cpp:34: note: versioning for alias required: can't determine dependence
between *D.22361_92 and *D.22353_81
Eyal.cpp:34: note: mark for run-time aliasing test between *D.22361_92 and
*D.22353_81
Eyal.cpp:34: note: versioning for alias required: can't determine dependence
between *D.22361_92 and *D.22365_101
Eyal.cpp:34: note: mark for run-time aliasing test between *D.22361_92 and
*D.22365_101
Eyal.cpp:34: note: versioning for alias required: can't determine dependence
between *D.22353_81 and *D.22365_101
Eyal.cpp:34: note: mark for run-time aliasing test between *D.22353_81 and
*D.22365_101
Eyal.cpp:34: note: versioning for alias required: can't determine dependence
between *D.22353_81 and *D.22367_105
Eyal.cpp:34: note: mark for run-time aliasing test between *D.22353_81 and
*D.22367_105
Eyal.cpp:34: note: versioning for alias required: can't determine dependence
between *D.22353_81 and *D.22371_112
Eyal.cpp:34: note: mark for run-time aliasing test between *D.22353_81 and
*D.22371_112
Eyal.cpp:34: note: versioning for alias required: can't determine dependence
between *D.22353_81 and *D.22365_101
Eyal.cpp:34: note: mark for run-time aliasing test between *D.22353_81 and
*D.22365_101
Eyal.cpp:34: note: dependence distance  = 0.
Eyal.cpp:34: note: accesses have the same alignment.
Eyal.cpp:34: note: dependence distance modulo vf == 0 between *D.22365_101 and
*D.22365_101
Eyal.cpp:34: note: versioning for alias required: can't determine dependence
between *D.22367_105 and *D.22365_101
Eyal.cpp:34: note: mark for run-time aliasing test between *D.22367_105 and
*D.22365_101
Eyal.cpp:34: note: versioning for alias required: can't determine dependence
between *D.22371_112 and *D.22365_101
Eyal.cpp:34: note: mark for run-time aliasing test between *D.22371_112 and
*D.22365_101
Eyal.cpp:34: note: found equal ranges *D.22353_81, *D.22365_101 and
*D.22353_81, *D.22365_101
Eyal.cpp:34: note: found equal ranges *D.22353_81, *D.22365_101 and
*D.22353_81, *D.22365_101
Eyal.cpp:34: note: === vect_analyze_slp ===
Eyal.cpp:34: note: === vect_make_slp_decision ===
Eyal.cpp:34: note: === vect_detect_hybrid_slp ===
Eyal.cpp:34: note: Alignment of access forced using versioning.
Eyal.cpp:34: note: Alignment of access forced using versioning.
Eyal.cpp:34: note: Vectorizing an unaligned access.
Eyal.cpp:34: note: Vectorizing an unaligned access.
Eyal.cpp:34: note: Vectorizing an unaligned access.
Eyal.cpp:34: note: Vectorizing an unaligned access.
Eyal.cpp:34: note: Vectorizing an unaligned access.
Eyal.cpp:34: note: Vectorizing an unaligned access.
Eyal.cpp:34: note: === vect_update_slp_costs_according_to_vf
===(analyze_scalar_evolution 
Eyal.cpp:34: note: create runtime check for data references *D.22353_81 and
*D.22365_101
Eyal.cpp:34: note: create runtime check for data references *D.22355_85 and
*D.22353_81
Eyal.cpp:34: note: create runtime check for data references *D.22355_85 and
*D.22365_101
Eyal.cpp:34: note: create runtime check for data references *D.22361_92 and
*D.22353_81
Eyal.cpp:34: note: create runtime check for data references *D.22361_92 and
*D.22365_101
Eyal.cpp:34: note: create runtime check for data references *D.22353_81 and
*D.22367_105
Eyal.cpp:34: note: create runtime check for data references *D.22353_81 and
*D.22371_112
Eyal.cpp:34: note: create runtime check for data references *D.22367_105 and
*D.22365_101
Eyal.cpp:34: note: create runtime check for data references *D.22371_112 and
*D.22365_101
Eyal.cpp:34: note: created 9 versioning for alias checks.
Eyal.cpp:34: note: LOOP VECTORIZED.(get_loop_exit_condition 


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35117