From f907cf4c07cf51863dadbe90894e2ae3382bada5 Mon Sep 17 00:00:00 2001 From: Kewen Lin Date: Tue, 14 Jun 2022 00:57:01 -0500 Subject: [PATCH] vect: Move suggested_unroll_factor applying [PR105940] As PR105940 shown, when rs6000 port tries to assign m_suggested_unroll_factor by 4 or so, there will be ICE on: exact_div (LOOP_VINFO_VECT_FACTOR (loop_vinfo), loop_vinfo->suggested_unroll_factor); In function vect_analyze_loop_2, the current place of suggested_unroll_factor applying can't guarantee it's applied for all cases. As the case shows, vectorizer could retry with SLP forced off, the vf is reset by saved_vectorization_factor which isn't applied with suggested_unroll_factor before. It means it can end up with one vf which neglects suggested_unroll_factor. I think it's off design, we should move the applying of suggested_unroll_factor after start_over. PR tree-optimization/105940 gcc/ChangeLog: * tree-vect-loop.cc (vect_analyze_loop_2): Move the place of applying suggested_unroll_factor after start_over. --- gcc/tree-vect-loop.cc | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/gcc/tree-vect-loop.cc b/gcc/tree-vect-loop.cc index 246347b9b08..e05f8e87f7d 100644 --- a/gcc/tree-vect-loop.cc +++ b/gcc/tree-vect-loop.cc @@ -2388,15 +2388,15 @@ vect_analyze_loop_2 (loop_vec_info loop_vinfo, bool &fatal, set of rgroups. */ gcc_assert (LOOP_VINFO_MASKS (loop_vinfo).is_empty ()); + /* This is the point where we can re-start analysis with SLP forced off. */ +start_over: + /* Apply the suggested unrolling factor, this was determined by the backend during finish_cost the first time we ran the analyzis for this vector mode. */ if (loop_vinfo->suggested_unroll_factor > 1) LOOP_VINFO_VECT_FACTOR (loop_vinfo) *= loop_vinfo->suggested_unroll_factor; - /* This is the point where we can re-start analysis with SLP forced off. */ -start_over: - /* Now the vectorization factor is final. */ poly_uint64 vectorization_factor = LOOP_VINFO_VECT_FACTOR (loop_vinfo); gcc_assert (known_ne (vectorization_factor, 0U)); -- 2.11.4.GIT