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From: "rguenther at suse dot de" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/53773] Vectorizer generates non-canonical multiplies
Date: Tue, 26 Jun 2012 08:36:00 -0000 [thread overview]
Message-ID: <bug-53773-4-lnWq4K06Ip@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-53773-4@http.gcc.gnu.org/bugzilla/>
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53773
--- Comment #2 from rguenther at suse dot de <rguenther at suse dot de> 2012-06-26 08:35:59 UTC ---
On Tue, 26 Jun 2012, jakub at gcc dot gnu.org wrote:
> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53773
>
> Jakub Jelinek <jakub at gcc dot gnu.org> changed:
>
> What |Removed |Added
> ----------------------------------------------------------------------------
> CC| |jakub at gcc dot gnu.org
>
> --- Comment #1 from Jakub Jelinek <jakub at gcc dot gnu.org> 2012-06-26 08:31:36 UTC ---
> Seems this is vect_is_simple_reduction_1's:
> if (check_reduction)
> {
> /* Swap operands (just for simplicity - so that the rest of the code
> can assume that the reduction variable is always the last (second)
> argument). */
> if (vect_print_dump_info (REPORT_DETAILS))
> report_vect_op (def_stmt,
> "detected reduction: need to swap operands: ");
>
> swap_tree_operands (def_stmt, gimple_assign_rhs1_ptr (def_stmt),
> gimple_assign_rhs2_ptr (def_stmt));
> }
>
> at least on the first testcase. Now, the question is how hard would it be to
> adjust the vectorizer so that it would work even without doing this swapping,
> or
> alternatively if we shouldn't canonicalize the operand order afterwards.
Or change it to "just for simplicity - ... that the reduction variable is
always the first argument.". Eventually that will wreck with reduction
of MINUS_EXPR though, not sure.
Richard.
next prev parent reply other threads:[~2012-06-26 8:36 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-06-25 22:16 [Bug tree-optimization/53773] New: " wschmidt at gcc dot gnu.org
2012-06-26 8:31 ` [Bug tree-optimization/53773] " jakub at gcc dot gnu.org
2012-06-26 8:36 ` rguenther at suse dot de [this message]
2012-06-26 8:52 ` rguenth at gcc dot gnu.org
2012-07-27 16:27 ` wschmidt at gcc dot gnu.org
2012-07-29 16:55 ` wschmidt at gcc dot gnu.org
2012-07-29 16:56 ` wschmidt at gcc dot gnu.org
2012-07-30 8:47 ` rguenther at suse dot de
2012-07-31 12:25 ` wschmidt at gcc dot gnu.org
2012-07-31 12:26 ` wschmidt at gcc dot gnu.org
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