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From: "jakub at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug tree-optimization/50789] Gather vectorization Date: Wed, 19 Oct 2011 09:03:00 -0000 [thread overview] Message-ID: <bug-50789-4-REaEyedbe4@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-50789-4@http.gcc.gnu.org/bugzilla/> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50789 --- Comment #3 from Jakub Jelinek <jakub at gcc dot gnu.org> 2011-10-19 09:02:26 UTC --- (In reply to comment #2) > We have something similar for SLP: if an access is not affine we just fill in > what we can. But I don't really understand what can be filled in for f3/f4. Well, we should be able to at least use TBAA in that case: void f5 (void) { int i; for (i = 0; i < N; i++) k[i] += *l[i]; } should be vectorizable too, as l[i] can't overlap k[i] (normal data dep) and *l[i], being float read, can't alias with k[i] either (int). Similarly perhaps: void f6 (float *__restrict f, float *__restrict *__restrict l) { int i; for (i = 0; i < N; i++) f[i] += *l[i]; } (though that one unlikely very soon). With these gather accesses we can't do any runtime alias checking before the loop, either we can prove there is no alias, or we can't vectorize. > Can't we treat it as an unconditional load for the dr analysis purposes? For that surely, but the conditional loads have other problems for the vectorizer, currently that means control flow within the loop. We'd need to transform it (perhaps temporarily or using pattern recognizer) to something without control flow that would still be clear on that the load is only conditional.
next prev parent reply other threads:[~2011-10-19 9:03 UTC|newest] Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top 2011-10-19 7:51 [Bug tree-optimization/50789] New: " jakub at gcc dot gnu.org 2011-10-19 8:10 ` [Bug tree-optimization/50789] " rguenth at gcc dot gnu.org 2011-10-19 8:49 ` irar at il dot ibm.com 2011-10-19 9:03 ` jakub at gcc dot gnu.org [this message] 2011-10-19 9:40 ` irar at il dot ibm.com 2011-10-24 8:40 ` jakub at gcc dot gnu.org 2011-10-25 21:17 ` jakub at gcc dot gnu.org 2011-10-26 16:57 ` jakub at gcc dot gnu.org 2011-11-07 16:02 ` jakub at gcc dot gnu.org 2011-11-08 13:26 ` jakub at gcc dot gnu.org 2013-04-02 16:50 ` vincenzo.innocente at cern dot ch 2013-04-17 8:31 ` andrey.turetskiy at gmail dot com 2013-04-17 8:53 ` rguenther at suse dot de 2013-07-03 9:22 ` vincenzo.innocente at cern dot ch
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