On 10 June 2011 12:14, Richard Guenther <richard.guent...@gmail.com> wrote: > On Fri, Jun 10, 2011 at 9:19 AM, Ira Rosen <ira.ro...@linaro.org> wrote: >> Hi, >> >> The test in PR 49318 fails because the vectorizer recognizes address >> computation sequence as a widening-multiplication pattern, while such >> sequence is not relevant to vectorization. The problem is that the >> vectorizer doesn't check if a statement is going to be vectorized >> before replacing it with a pattern. Moreover, the vectorizer first >> detects the patterns and only after that looks for relevant >> statements. Changing the order is not a good option, since statements >> relevance is defined also by their belonging to a pattern. >> >> This patch solves the problem by removing pattern statements that were >> created for statements that are not supposed to be vectorized. >> >> Bootstrapped with vectorization enabled on powerpc64-suse-linux and >> tested on powerpc64-suse-linux and x86_64-suse-linux. >> Committed. > > Ick, yeah. I remember running into this ordering issue when doing the > multi-vector size reorgs... > > In the end I think we should not generate the pattern stmt during > pattern matching but only mark the relevant statements with a > pattern kind. Say, for each pattern we have a "main" statement > that has related stmts belonging to the pattern that define uses > of the "main" statement - mark those to refer to that "main" statement. > For that "main" statement simply record an enum value, like, > widening_mult. Then only at vectorized statement > generation time actually generate the vectorized form of the > pattern statement. > > Thus, the non-vectorized pattern statements would never be generated. > > So, separate analysis and transform more properly. > > Of course I didn't get around to implement the above ... (we'd have > a new vectorizable_pattern worker).
Sounds like a good idea. I'll give it a try. Thanks, Ira > > Richard. > >> Ira >> >> ChangeLog: >> >> PR tree-optimization/49318 >> * tree-vect-loop.c (vect_determine_vectorization_factor): >> Remove irrelevant pattern statements. >> >> testsuite/ChangeLog: >> >> PR tree-optimization/49318 >> * gcc.dg/vect/pr49318.c: New test. >> >
