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[Bug middle-end/32624] [4.3 Regression] r126198 causes tramp3d slowdown w/o leafify
- From: "rguenth at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 4 Jul 2007 16:11:13 -0000
- Subject: [Bug middle-end/32624] [4.3 Regression] r126198 causes tramp3d slowdown w/o leafify
- References: <bug-32624-10053@http.gcc.gnu.org/bugzilla/>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Comment #1 from rguenth at gcc dot gnu dot org 2007-07-04 16:11 -------
This seems to be an aliasing problem. Somehow we do not prune SMTs enough
after
the patch. MPT grouping doesn't trigger in.
An example function to look at is (x86_64)
_ZN14MultiArgKernelI9MultiArg4I5FieldI22UniformRectilinearMeshI10MeshTraitsILi3Ed21UniformRectilinearTag12CartesianTagLi3EEEd10BrickViewUES9_S9_S9_E15EvaluateLocLoopIN6Forgas5CentYILi3EEELi3EEE3runEv
if you look at the alias6 dump (the one before lim which does no longer move
invariant integer loads out of the inner loop) you can see:
without the patch:
# VUSE <SMT.21607_161(D)>
D.852018_33 =
op$multiArg_m_7->a1_m.fieldEngine_m.data_m.blockControllerPtr_m.ptr_m;
with the patch (only the tree-inline.c part is actually necessary):
# VUSE <SMT.21592_132(D), SMT.21595_227>
D.854673_30 =
op$multiArg_m_19->a1_m.fieldEngine_m.data_m.blockControllerPtr_m.ptr_m;
it doesn't make sense that there is a difference in pruning. Really.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32624