On Mon, Jul 4, 2011 at 6:28 AM, H.J. Lu <hjl.to...@gmail.com> wrote: > On Wed, Jun 29, 2011 at 4:19 AM, Richard Guenther <rguent...@suse.de> wrote: >> >> The following patch makes us handle invariant loads during vectorization. >> Dependence analysis currently isn't clever enough to disambiguate them >> thus we insert versioning-for-alias checks. For the testcase hoisting >> the load is still always possible though, and for a read-after-write >> dependence it would be possible for the vectorized loop copy as the >> may-aliasing write is varying by the scalar variable size. >> >> The existing code for vectorizing invariant accesses looks very >> suspicious - it generates a vector load at the scalar address >> to then just extract the first vector element. Huh. IMHO this >> can be simplified as done, by just re-using the scalar load result. >> But maybe this code was supposed to deal with something entirely >> different? >> >> This patch gives a 33% speedup to the phoronix himeno testcase >> if you bump the maximum alias versioning checks we want to insert. >> >> I'm currently re-bootstrapping & testing this but an earlier version >> was ok on x86_64-unknown-linux-gnu. >> >> 2011-06-29 Richard Guenther <rguent...@suse.de> >> >> PR tree-optimization/46787 >> * tree-data-ref.c (dr_address_invariant_p): Remove. >> (find_data_references_in_stmt): Invariant accesses are ok now. >> * tree-vect-stmts.c (vectorizable_load): Handle invariant >> loads. >> * tree-vect-data-refs.c (vect_analyze_data_ref_access): Allow >> invariant loads. >> >> * gcc.dg/vect/vect-121.c: New testcase. >> > > This also caused: > > http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49628 > >
It also caused: http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49893 -- H.J.
