From 2130efe6ac7beba72d289e3dd145daa10aeaed54 Mon Sep 17 00:00:00 2001 From: Richard Biener Date: Wed, 26 Aug 2020 15:12:17 +0200 Subject: [PATCH] tree-optimization/96698 - fix ICE when vectorizing nested cycles This fixes vectorized PHI latch edge updating and delay it until all of the loop is code generated to deal with the case that the latch def is a PHI in the same block. 2020-08-26 Richard Biener PR tree-optimization/96698 * tree-vectorizer.h (loop_vec_info::reduc_latch_defs): New. (loop_vec_info::reduc_latch_slp_defs): Likewise. * tree-vect-stmts.c (vect_transform_stmt): Only record stmts to update PHI latches from, perform the update ... * tree-vect-loop.c (vect_transform_loop): ... here after vectorizing those PHIs. (info_for_reduction): Properly handle non-reduction PHIs. * gcc.dg/vect/pr96698.c: New testcase. --- gcc/testsuite/gcc.dg/vect/pr96698.c | 19 +++++++++++++++++++ gcc/tree-vect-loop.c | 35 ++++++++++++++++++++++++++++++++++- gcc/tree-vect-stmts.c | 29 +++++------------------------ gcc/tree-vectorizer.h | 5 +++++ 4 files changed, 63 insertions(+), 25 deletions(-) create mode 100644 gcc/testsuite/gcc.dg/vect/pr96698.c diff --git a/gcc/testsuite/gcc.dg/vect/pr96698.c b/gcc/testsuite/gcc.dg/vect/pr96698.c new file mode 100644 index 0000000..1d141c1 --- /dev/null +++ b/gcc/testsuite/gcc.dg/vect/pr96698.c @@ -0,0 +1,19 @@ +/* { dg-do compile } */ + +void test(int a, int* i) +{ + for (; a < 5; ++a) + { + int b = 0; + int c = 0; + for (; b != -11; b--) + for (int d = 0; d ==0; d++) + { + *i += c & a; + c = b; + } + } +} + +/* We should be able to vectorize the inner cycle. */ +/* { dg-final { scan-tree-dump "OUTER LOOP VECTORIZED" "vect" { target vect_int } } } */ diff --git a/gcc/tree-vect-loop.c b/gcc/tree-vect-loop.c index a92813e..50abb2b 100644 --- a/gcc/tree-vect-loop.c +++ b/gcc/tree-vect-loop.c @@ -4646,7 +4646,8 @@ info_for_reduction (vec_info *vinfo, stmt_vec_info stmt_info) { stmt_info = vect_orig_stmt (stmt_info); gcc_assert (STMT_VINFO_REDUC_DEF (stmt_info)); - if (!is_a (stmt_info->stmt)) + if (!is_a (stmt_info->stmt) + || !VECTORIZABLE_CYCLE_DEF (STMT_VINFO_DEF_TYPE (stmt_info))) stmt_info = STMT_VINFO_REDUC_DEF (stmt_info); gphi *phi = as_a (stmt_info->stmt); if (STMT_VINFO_DEF_TYPE (stmt_info) == vect_double_reduction_def) @@ -9031,6 +9032,38 @@ vect_transform_loop (loop_vec_info loop_vinfo, gimple *loop_vectorized_call) } } + /* Fill in backedge defs of reductions. */ + for (unsigned i = 0; i < loop_vinfo->reduc_latch_defs.length (); ++i) + { + stmt_vec_info stmt_info = loop_vinfo->reduc_latch_defs[i]; + stmt_vec_info orig_stmt_info = vect_orig_stmt (stmt_info); + vec &phi_info + = STMT_VINFO_VEC_STMTS (STMT_VINFO_REDUC_DEF (orig_stmt_info)); + vec &vec_stmt + = STMT_VINFO_VEC_STMTS (stmt_info); + gcc_assert (phi_info.length () == vec_stmt.length ()); + gphi *phi + = dyn_cast (STMT_VINFO_REDUC_DEF (orig_stmt_info)->stmt); + edge e = loop_latch_edge (gimple_bb (phi_info[0])->loop_father); + for (unsigned j = 0; j < phi_info.length (); ++j) + add_phi_arg (as_a (phi_info[j]), + gimple_get_lhs (vec_stmt[j]), e, + gimple_phi_arg_location (phi, e->dest_idx)); + } + for (unsigned i = 0; i < loop_vinfo->reduc_latch_slp_defs.length (); ++i) + { + slp_tree slp_node = loop_vinfo->reduc_latch_slp_defs[i].first; + slp_tree phi_node = loop_vinfo->reduc_latch_slp_defs[i].second; + gphi *phi = as_a (SLP_TREE_SCALAR_STMTS (phi_node)[0]->stmt); + e = loop_latch_edge (gimple_bb (phi)->loop_father); + gcc_assert (SLP_TREE_VEC_STMTS (phi_node).length () + == SLP_TREE_VEC_STMTS (slp_node).length ()); + for (unsigned j = 0; j < SLP_TREE_VEC_STMTS (phi_node).length (); ++j) + add_phi_arg (as_a (SLP_TREE_VEC_STMTS (phi_node)[j]), + vect_get_slp_vect_def (slp_node, j), + e, gimple_phi_arg_location (phi, e->dest_idx)); + } + /* Stub out scalar statements that must not survive vectorization. Doing this here helps with grouped statements, or statements that are involved in patterns. */ diff --git a/gcc/tree-vect-stmts.c b/gcc/tree-vect-stmts.c index 224be01..04d202e 100644 --- a/gcc/tree-vect-stmts.c +++ b/gcc/tree-vect-stmts.c @@ -10920,8 +10920,8 @@ vect_transform_stmt (vec_info *vinfo, if (STMT_VINFO_TYPE (stmt_info) == store_vec_info_type) return is_store; - /* If this stmt defines a value used on a backedge, update the - vectorized PHIs. */ + /* If this stmt defines a value used on a backedge, record it so + we can update the vectorized PHIs later. */ stmt_vec_info orig_stmt_info = vect_orig_stmt (stmt_info); stmt_vec_info reduc_info; if (STMT_VINFO_REDUC_DEF (orig_stmt_info) @@ -10940,30 +10940,11 @@ vect_transform_stmt (vec_info *vinfo, && (e = loop_latch_edge (gimple_bb (phi)->loop_father)) && (PHI_ARG_DEF_FROM_EDGE (phi, e) == gimple_get_lhs (orig_stmt_info->stmt))) - { - vec &phi_info - = STMT_VINFO_VEC_STMTS (STMT_VINFO_REDUC_DEF (orig_stmt_info)); - vec &vec_stmt - = STMT_VINFO_VEC_STMTS (stmt_info); - gcc_assert (phi_info.length () == vec_stmt.length ()); - for (unsigned i = 0; i < phi_info.length (); ++i) - add_phi_arg (as_a (phi_info[i]), - gimple_get_lhs (vec_stmt[i]), e, - gimple_phi_arg_location (phi, e->dest_idx)); - } + as_a (vinfo)->reduc_latch_defs.safe_push (stmt_info); else if (slp_node && slp_node != slp_node_instance->reduc_phis) - { - slp_tree phi_node = slp_node_instance->reduc_phis; - gphi *phi = as_a (SLP_TREE_SCALAR_STMTS (phi_node)[0]->stmt); - e = loop_latch_edge (gimple_bb (phi)->loop_father); - gcc_assert (SLP_TREE_VEC_STMTS (phi_node).length () - == SLP_TREE_VEC_STMTS (slp_node).length ()); - for (unsigned i = 0; i < SLP_TREE_VEC_STMTS (phi_node).length (); ++i) - add_phi_arg (as_a (SLP_TREE_VEC_STMTS (phi_node)[i]), - vect_get_slp_vect_def (slp_node, i), - e, gimple_phi_arg_location (phi, e->dest_idx)); - } + as_a (vinfo)->reduc_latch_slp_defs.safe_push + (std::make_pair (slp_node, slp_node_instance->reduc_phis)); } /* Handle stmts whose DEF is used outside the loop-nest that is diff --git a/gcc/tree-vectorizer.h b/gcc/tree-vectorizer.h index 8551b68..f36e2ad 100644 --- a/gcc/tree-vectorizer.h +++ b/gcc/tree-vectorizer.h @@ -627,6 +627,11 @@ public: stmt in the chain. */ auto_vec reduction_chains; + /* The vectorized stmts defining the latch values of the reduction + they are involved with. */ + auto_vec reduc_latch_defs; + auto_vec > reduc_latch_slp_defs; + /* Cost vector for a single scalar iteration. */ auto_vec scalar_cost_vec; -- 2.7.4