On Thu, May 28, 2015 at 1:00 PM, Yuri Rumyantsev <ysrum...@gmail.com> wrote: > Hi All, > > Here is a simple patch which removes restriction on outer-loop > vectorization - allow references in inner-loop with zero step. This > case was found in one important benchmark. > > Bootstrap and regression testing did not show any new failures. > Is it OK for trunk. > > ChangeLog: > 2015-05-28 Yuri Rumyantsev <ysrum...@gmail.com> > > * tree-vect-data-refs.c (vect_analyze_data_ref_access): Allow > consecutive accesses within outer-loop vectorization for references > with zero step in inner-loop. > > gcc/testsuite/ChangeLog: > * gcc.dg/vect/fast-math-vect-outer-1.c: New test.
Can you please add a non-omp-simd testcase that triggers this as well and that is a runtime testcase verifying the transform is correct? Also please don't add to the strange testcase-name machinery but just use { dg-additional-options "-ffast-math" } Index: tree-vect-data-refs.c =================================================================== --- tree-vect-data-refs.c (revision 223653) +++ tree-vect-data-refs.c (working copy) @@ -2261,7 +2261,6 @@ return true; } - /* Analyze the access pattern of the data-reference DR. In case of non-consecutive accesses call vect_analyze_group_access() to analyze groups of accesses. */ spurious white-space change @@ -2291,14 +2290,8 @@ if (loop_vinfo && integer_zerop (step)) Surely the comment before this needs updating now. { GROUP_FIRST_ELEMENT (vinfo_for_stmt (stmt)) = NULL; - if (nested_in_vect_loop_p (loop, stmt)) - { - if (dump_enabled_p ()) - dump_printf_loc (MSG_NOTE, vect_location, - "zero step in inner loop of nest\n"); - return false; - } - return DR_IS_READ (dr); + if (!nested_in_vect_loop_p (loop, stmt)) + return DR_IS_READ (dr); } if (loop && nested_in_vect_loop_p (loop, stmt)) so what happens after the patch? It would be nice to have a comment explaining what happens in the nested_in_vect_loop_p case for the case when the outer-loop step is zero and when it is not zero. In particular as you don't need any code generation changes - this hints at that you may miss something ;) Otherwise of course the patch is ok - lifting restrictions is good. Thanks, Richard.