From bd0f22a8d5caea8905f38ff1fafce31c1b7d33ad Mon Sep 17 00:00:00 2001 From: Kewen Lin Date: Tue, 31 Mar 2020 22:48:46 -0500 Subject: [PATCH] Fix PR94043 by making vect_live_op generate lc-phi As PR94043 shows, my commit r10-4524 exposed one issue in vectorizable_live_operation, which inserts one extra BB before the single exit, leading unexpected operand expansion and unexpected loop depth assertion. As Richi suggested, this patch is to teach vectorizable_live_operation to generate loop closed phi for vec_lhs, it looks like: loop; # lhs' = PHI => loop; # vec_lhs' = PHI new_tree = BIT_FIELD_REF ; lhs' = new_tree; I noticed that there are some SLP cases that have same lhs and vec_lhs but different offsets, which can make us have more PHIs for the same vec_lhs there. But I think it would be fine since only one of them is actually live, the others should be eliminated by the following dce. So the patch doesn't check whether there is one phi for vec_lhs, just create one directly instead. Bootstrapped/regtested on powerpc64le-linux-gnu (LE) P8. 2020-04-01 Kewen Lin gcc/ChangeLog PR tree-optimization/94043 * tree-vect-loop.c (vectorizable_live_operation): Generate loop-closed phi for vec_lhs and use it for lane extraction. gcc/testsuite/ChangeLog PR tree-optimization/94043 * gfortran.dg/graphite/vect-pr94043.f90: New test. --- gcc/ChangeLog | 6 +++ gcc/testsuite/ChangeLog | 5 ++ .../gfortran.dg/graphite/vect-pr94043.f90 | 18 +++++++ gcc/tree-vect-loop.c | 50 ++++++++++++++++--- 4 files changed, 73 insertions(+), 6 deletions(-) create mode 100644 gcc/testsuite/gfortran.dg/graphite/vect-pr94043.f90 diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 5bd72ccddd9..fc836b83e17 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,9 @@ +2020-04-01 Kewen Lin + + PR tree-optimization/94043 + * tree-vect-loop.c (vectorizable_live_operation): Generate loop-closed + phi for vec_lhs and use it for lane extraction. + 2020-03-31 Felix Yang PR tree-optimization/94398 diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index adfbdb01af7..6f41ffbb048 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,8 @@ +2020-04-01 Kewen Lin + + PR tree-optimization/94043 + * gfortran.dg/graphite/vect-pr94043.f90: New test. + 2020-04-01 Iain Buclaw PR d/90136 diff --git a/gcc/testsuite/gfortran.dg/graphite/vect-pr94043.f90 b/gcc/testsuite/gfortran.dg/graphite/vect-pr94043.f90 new file mode 100644 index 00000000000..744c0f3042e --- /dev/null +++ b/gcc/testsuite/gfortran.dg/graphite/vect-pr94043.f90 @@ -0,0 +1,18 @@ +! { dg-do compile } +! { dg-additional-options "-O3 -ftree-parallelize-loops=2 -fno-tree-dce" } + +! As PR94043, test it to be compiled successfully without ICE. + +program yw + integer :: hx(6, 6) + integer :: ps = 1, e2 = 1 + + do ps = 1, 6 + do e2 = 1, 6 + hx(e2, ps) = 0 + if (ps >= 5 .and. e2 >= 5) then + hx(e2, ps) = hx(1, 1) + end if + end do + end do +end program diff --git a/gcc/tree-vect-loop.c b/gcc/tree-vect-loop.c index 73e092c1d6c..c9b653491f7 100644 --- a/gcc/tree-vect-loop.c +++ b/gcc/tree-vect-loop.c @@ -7998,6 +7998,25 @@ vectorizable_live_operation (stmt_vec_info stmt_info, bitstart = int_const_binop (MINUS_EXPR, vec_bitsize, bitsize); } + /* Ensure the VEC_LHS for lane extraction stmts satisfy loop-closed PHI + requirement, insert one phi node for it. It looks like: + loop; + BB: + # lhs' = PHI + ==> + loop; + BB: + # vec_lhs' = PHI + new_tree = lane_extract ; + lhs' = new_tree; */ + + basic_block exit_bb = single_exit (loop)->dest; + gcc_assert (single_pred_p (exit_bb)); + + tree vec_lhs_phi = copy_ssa_name (vec_lhs); + gimple *phi = create_phi_node (vec_lhs_phi, exit_bb); + SET_PHI_ARG_DEF (phi, single_exit (loop)->dest_idx, vec_lhs); + gimple_seq stmts = NULL; tree new_tree; if (LOOP_VINFO_FULLY_MASKED_P (loop_vinfo)) @@ -8010,10 +8029,10 @@ vectorizable_live_operation (stmt_vec_info stmt_info, the loop mask for the final iteration. */ gcc_assert (ncopies == 1 && !slp_node); tree scalar_type = TREE_TYPE (STMT_VINFO_VECTYPE (stmt_info)); - tree mask = vect_get_loop_mask (gsi, &LOOP_VINFO_MASKS (loop_vinfo), - 1, vectype, 0); - tree scalar_res = gimple_build (&stmts, CFN_EXTRACT_LAST, - scalar_type, mask, vec_lhs); + tree mask = vect_get_loop_mask (gsi, &LOOP_VINFO_MASKS (loop_vinfo), 1, + vectype, 0); + tree scalar_res = gimple_build (&stmts, CFN_EXTRACT_LAST, scalar_type, + mask, vec_lhs_phi); /* Convert the extracted vector element to the required scalar type. */ new_tree = gimple_convert (&stmts, lhs_type, scalar_res); @@ -8023,13 +8042,32 @@ vectorizable_live_operation (stmt_vec_info stmt_info, tree bftype = TREE_TYPE (vectype); if (VECTOR_BOOLEAN_TYPE_P (vectype)) bftype = build_nonstandard_integer_type (tree_to_uhwi (bitsize), 1); - new_tree = build3 (BIT_FIELD_REF, bftype, vec_lhs, bitsize, bitstart); + new_tree = build3 (BIT_FIELD_REF, bftype, vec_lhs_phi, bitsize, bitstart); new_tree = force_gimple_operand (fold_convert (lhs_type, new_tree), &stmts, true, NULL_TREE); } if (stmts) - gsi_insert_seq_on_edge_immediate (single_exit (loop), stmts); + { + gimple_stmt_iterator exit_gsi = gsi_after_labels (exit_bb); + gsi_insert_before (&exit_gsi, stmts, GSI_CONTINUE_LINKING); + + /* Remove existing phi from lhs and create one copy from new_tree. */ + tree lhs_phi = NULL_TREE; + gimple_stmt_iterator gsi; + for (gsi = gsi_start_phis (exit_bb); !gsi_end_p (gsi); gsi_next (&gsi)) + { + gimple *phi = gsi_stmt (gsi); + if ((gimple_phi_arg_def (phi, 0) == lhs)) + { + remove_phi_node (&gsi, false); + lhs_phi = gimple_phi_result (phi); + gimple *copy = gimple_build_assign (lhs_phi, new_tree); + gsi_insert_after (&exit_gsi, copy, GSI_CONTINUE_LINKING); + break; + } + } + } /* Replace use of lhs with newly computed result. If the use stmt is a single arg PHI, just replace all uses of PHI result. It's necessary -- 2.30.2