On Tue, Jul 26, 2016 at 7:11 PM, Bin Cheng <bin.ch...@arm.com> wrote:
> Hi,
> This patch vectorizes possible infinite loops by versioning. It analyzes
> loops considered for vectorization using loop constraint facility which was
> introduced by previous patch; then vectorizes the loop with respect to
> assumptions of loop niters information; at last, it sets constraint flags for
> versioned loop so that niter analyzer in following optimizers can take
> advantage of it. The patch also adds two tests.
>
> Bootstrap and test on x86_64. Any comments?
+ else if (integer_nonzerop (may_be_zero))
+ {
+ niter = build_int_cst (TREE_TYPE (niter), 0);
+ *number_of_iterationsm1 = niter;
+ *number_of_iterations = niter;
*number_of_iterations should be 1 here.
Otherwise the patch looks ok to me.
Thanks,
RIchard.
> Thanks,
> bin
>
> 2016-07-25 Bin Cheng <bin.ch...@arm.com>
>
> PR tree-optimization/57558
> * tree-vect-loop-manip.c (vect_create_cond_for_niters_checks): New
> function.
> (vect_loop_versioning): Support versioning with niter assumptions.
> * tree-vect-loop.c (tree-ssa-loop.h): Include header file.
> (vect_get_loop_niters): New parameter. Reimplement to support
> assumptions in loop niter info.
> (vect_analyze_loop_form_1, vect_analyze_loop_form): Ditto.
> (new_loop_vec_info): Init LOOP_VINFO_NITERS_ASSUMPTIONS.
> (vect_estimate_min_profitable_iters): Use LOOP_REQUIRES_VERSIONING.
> Support loop versioning for niters.
> * tree-vectorizer.c (tree-ssa-loop-niter.h): Include header file.
> (vect_free_loop_info_assumptions): New function.
> (vectorize_loops): Free loop niter info for loops with flag
> LOOP_F_ASSUMPTIONS set if vectorization failed.
> * tree-vectorizer.h (struct _loop_vec_info): New field
> num_iters_assumptions.
> (LOOP_VINFO_NITERS_ASSUMPTIONS): New macro.
> (LOOP_REQUIRES_VERSIONING_FOR_NITERS): New macro.
> (LOOP_REQUIRES_VERSIONING): New macro.
> (vect_free_loop_info_assumptions): New decl.
>
> gcc/testsuite/ChangeLog
> 2016-07-25 Bin Cheng <bin.ch...@arm.com>
>
> PR tree-optimization/57558
> * gcc.dg/vect/pr57558-1.c: New test.
> * gcc.dg/vect/pr57558-2.c: New test.
