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304afda64b
* lambda-code.c (lambda_transform_legal_p): Use DDR_NUM_DIST_VECTS for testing whether the data_dependence_relation contains distance vectors. Iterate over all distance vectors of the ddr. * lambda.h: Define a vec of lambda_vector pointers. * tree-data-ref.c (dump_data_dependence_relation, dump_data_dependence_direction): Iterate over all distance and direction vectors of the ddr. (initialize_data_dependence_relation): Initialize DDR_DIR_VECTS and DDR_DIST_VECTS. (build_classic_dist_vector, build_classic_dir_vector): Push a set of distance/direction vectors instead of a single one. * tree-data-ref.h (dir_vects, dist_vects): Replace dir/dist lambda_vectors with a vec of lambda_vectors. (DDR_DIR_VECT, DDR_DIST_VECT): Redefined as operations on vec. (DDR_DIR_VECTS, DDR_DIST_VECTS, DDR_NUM_DIR_VECTS, DDR_NUM_DIST_VECTS): New. * tree-loop-linear.c (gather_interchange_stats): Test for the existence of distance vectors only after having checked that there is a dependence. Iterate over all distance vectors of the ddr. (linear_transform_loops): Use dump_data_dependence_relation. * tree-vect-analyze.c (vect_analyze_data_ref_dependence): Test for distance vectors using DDR_NUM_DIST_VECTS. Iterate over all the distance vectors of the ddr. From-SVN: r106530
2089 lines
65 KiB
C
2089 lines
65 KiB
C
/* Analysis Utilities for Loop Vectorization.
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Copyright (C) 2003,2004,2005 Free Software Foundation, Inc.
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Contributed by Dorit Naishlos <dorit@il.ibm.com>
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This file is part of GCC.
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GCC is free software; you can redistribute it and/or modify it under
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the terms of the GNU General Public License as published by the Free
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Software Foundation; either version 2, or (at your option) any later
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version.
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GCC is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or
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FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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for more details.
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You should have received a copy of the GNU General Public License
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along with GCC; see the file COPYING. If not, write to the Free
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Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
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02110-1301, USA. */
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#include "config.h"
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#include "system.h"
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#include "coretypes.h"
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#include "tm.h"
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#include "ggc.h"
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#include "tree.h"
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#include "basic-block.h"
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#include "diagnostic.h"
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#include "tree-flow.h"
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#include "tree-dump.h"
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#include "timevar.h"
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#include "cfgloop.h"
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#include "expr.h"
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#include "optabs.h"
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#include "params.h"
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#include "tree-chrec.h"
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#include "tree-data-ref.h"
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#include "tree-scalar-evolution.h"
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#include "tree-vectorizer.h"
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/* Main analysis functions. */
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static loop_vec_info vect_analyze_loop_form (struct loop *);
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static bool vect_analyze_data_refs (loop_vec_info);
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static bool vect_mark_stmts_to_be_vectorized (loop_vec_info);
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static void vect_analyze_scalar_cycles (loop_vec_info);
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static bool vect_analyze_data_ref_accesses (loop_vec_info);
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static bool vect_analyze_data_ref_dependences (loop_vec_info);
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static bool vect_analyze_data_refs_alignment (loop_vec_info);
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static bool vect_compute_data_refs_alignment (loop_vec_info);
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static bool vect_enhance_data_refs_alignment (loop_vec_info);
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static bool vect_analyze_operations (loop_vec_info);
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static bool vect_determine_vectorization_factor (loop_vec_info);
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/* Utility functions for the analyses. */
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static bool exist_non_indexing_operands_for_use_p (tree, tree);
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static void vect_mark_relevant (VEC(tree,heap) **, tree, bool, bool);
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static bool vect_stmt_relevant_p (tree, loop_vec_info, bool *, bool *);
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static tree vect_get_loop_niters (struct loop *, tree *);
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static bool vect_analyze_data_ref_dependence
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(struct data_dependence_relation *, loop_vec_info);
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static bool vect_compute_data_ref_alignment (struct data_reference *);
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static bool vect_analyze_data_ref_access (struct data_reference *);
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static bool vect_can_advance_ivs_p (loop_vec_info);
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static void vect_update_misalignment_for_peel
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(struct data_reference *, struct data_reference *, int npeel);
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/* Function vect_determine_vectorization_factor
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Determine the vectorization factor (VF). VF is the number of data elements
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that are operated upon in parallel in a single iteration of the vectorized
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loop. For example, when vectorizing a loop that operates on 4byte elements,
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on a target with vector size (VS) 16byte, the VF is set to 4, since 4
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elements can fit in a single vector register.
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We currently support vectorization of loops in which all types operated upon
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are of the same size. Therefore this function currently sets VF according to
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the size of the types operated upon, and fails if there are multiple sizes
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in the loop.
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VF is also the factor by which the loop iterations are strip-mined, e.g.:
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original loop:
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for (i=0; i<N; i++){
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a[i] = b[i] + c[i];
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}
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vectorized loop:
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for (i=0; i<N; i+=VF){
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a[i:VF] = b[i:VF] + c[i:VF];
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}
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*/
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static bool
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vect_determine_vectorization_factor (loop_vec_info loop_vinfo)
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{
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struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo);
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basic_block *bbs = LOOP_VINFO_BBS (loop_vinfo);
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int nbbs = loop->num_nodes;
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block_stmt_iterator si;
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unsigned int vectorization_factor = 0;
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int i;
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tree scalar_type;
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if (vect_print_dump_info (REPORT_DETAILS))
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fprintf (vect_dump, "=== vect_determine_vectorization_factor ===");
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for (i = 0; i < nbbs; i++)
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{
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basic_block bb = bbs[i];
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for (si = bsi_start (bb); !bsi_end_p (si); bsi_next (&si))
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{
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tree stmt = bsi_stmt (si);
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unsigned int nunits;
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stmt_vec_info stmt_info = vinfo_for_stmt (stmt);
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tree vectype;
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if (vect_print_dump_info (REPORT_DETAILS))
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{
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fprintf (vect_dump, "==> examining statement: ");
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print_generic_expr (vect_dump, stmt, TDF_SLIM);
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}
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gcc_assert (stmt_info);
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/* skip stmts which do not need to be vectorized. */
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if (!STMT_VINFO_RELEVANT_P (stmt_info)
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&& !STMT_VINFO_LIVE_P (stmt_info))
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{
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if (vect_print_dump_info (REPORT_DETAILS))
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fprintf (vect_dump, "skip.");
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continue;
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}
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if (VECTOR_MODE_P (TYPE_MODE (TREE_TYPE (stmt))))
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{
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if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS))
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{
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fprintf (vect_dump, "not vectorized: vector stmt in loop:");
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print_generic_expr (vect_dump, stmt, TDF_SLIM);
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}
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return false;
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}
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if (STMT_VINFO_DATA_REF (stmt_info))
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scalar_type = TREE_TYPE (DR_REF (STMT_VINFO_DATA_REF (stmt_info)));
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else if (TREE_CODE (stmt) == MODIFY_EXPR)
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scalar_type = TREE_TYPE (TREE_OPERAND (stmt, 0));
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else
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scalar_type = TREE_TYPE (stmt);
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if (vect_print_dump_info (REPORT_DETAILS))
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{
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fprintf (vect_dump, "get vectype for scalar type: ");
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print_generic_expr (vect_dump, scalar_type, TDF_SLIM);
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}
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vectype = get_vectype_for_scalar_type (scalar_type);
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if (!vectype)
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{
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if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS))
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{
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fprintf (vect_dump, "not vectorized: unsupported data-type ");
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print_generic_expr (vect_dump, scalar_type, TDF_SLIM);
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}
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return false;
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}
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if (vect_print_dump_info (REPORT_DETAILS))
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{
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fprintf (vect_dump, "vectype: ");
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print_generic_expr (vect_dump, vectype, TDF_SLIM);
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}
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STMT_VINFO_VECTYPE (stmt_info) = vectype;
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nunits = TYPE_VECTOR_SUBPARTS (vectype);
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if (vect_print_dump_info (REPORT_DETAILS))
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fprintf (vect_dump, "nunits = %d", nunits);
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if (vectorization_factor)
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{
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/* FORNOW: don't allow mixed units.
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This restriction will be relaxed in the future. */
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if (nunits != vectorization_factor)
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{
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if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS))
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fprintf (vect_dump, "not vectorized: mixed data-types");
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return false;
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}
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}
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else
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vectorization_factor = nunits;
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gcc_assert (GET_MODE_SIZE (TYPE_MODE (scalar_type))
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* vectorization_factor == UNITS_PER_SIMD_WORD);
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}
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}
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/* TODO: Analyze cost. Decide if worth while to vectorize. */
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if (vectorization_factor <= 1)
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{
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if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS))
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fprintf (vect_dump, "not vectorized: unsupported data-type");
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return false;
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}
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LOOP_VINFO_VECT_FACTOR (loop_vinfo) = vectorization_factor;
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return true;
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}
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/* Function vect_analyze_operations.
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Scan the loop stmts and make sure they are all vectorizable. */
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static bool
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vect_analyze_operations (loop_vec_info loop_vinfo)
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{
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struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo);
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basic_block *bbs = LOOP_VINFO_BBS (loop_vinfo);
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int nbbs = loop->num_nodes;
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block_stmt_iterator si;
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unsigned int vectorization_factor = 0;
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int i;
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bool ok;
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tree phi;
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stmt_vec_info stmt_info;
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bool need_to_vectorize = false;
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if (vect_print_dump_info (REPORT_DETAILS))
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fprintf (vect_dump, "=== vect_analyze_operations ===");
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gcc_assert (LOOP_VINFO_VECT_FACTOR (loop_vinfo));
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vectorization_factor = LOOP_VINFO_VECT_FACTOR (loop_vinfo);
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for (i = 0; i < nbbs; i++)
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{
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basic_block bb = bbs[i];
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for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
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{
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stmt_info = vinfo_for_stmt (phi);
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if (vect_print_dump_info (REPORT_DETAILS))
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{
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fprintf (vect_dump, "examining phi: ");
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print_generic_expr (vect_dump, phi, TDF_SLIM);
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}
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gcc_assert (stmt_info);
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if (STMT_VINFO_LIVE_P (stmt_info))
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{
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/* FORNOW: not yet supported. */
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if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS))
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fprintf (vect_dump, "not vectorized: value used after loop.");
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return false;
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}
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if (STMT_VINFO_RELEVANT_P (stmt_info))
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{
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/* Most likely a reduction-like computation that is used
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in the loop. */
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if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS))
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fprintf (vect_dump, "not vectorized: unsupported pattern.");
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return false;
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}
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}
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for (si = bsi_start (bb); !bsi_end_p (si); bsi_next (&si))
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{
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tree stmt = bsi_stmt (si);
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stmt_vec_info stmt_info = vinfo_for_stmt (stmt);
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if (vect_print_dump_info (REPORT_DETAILS))
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{
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fprintf (vect_dump, "==> examining statement: ");
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print_generic_expr (vect_dump, stmt, TDF_SLIM);
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}
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gcc_assert (stmt_info);
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/* skip stmts which do not need to be vectorized.
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this is expected to include:
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- the COND_EXPR which is the loop exit condition
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- any LABEL_EXPRs in the loop
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- computations that are used only for array indexing or loop
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control */
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if (!STMT_VINFO_RELEVANT_P (stmt_info)
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&& !STMT_VINFO_LIVE_P (stmt_info))
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{
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if (vect_print_dump_info (REPORT_DETAILS))
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fprintf (vect_dump, "irrelevant.");
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continue;
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}
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if (STMT_VINFO_RELEVANT_P (stmt_info))
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{
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gcc_assert (!VECTOR_MODE_P (TYPE_MODE (TREE_TYPE (stmt))));
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gcc_assert (STMT_VINFO_VECTYPE (stmt_info));
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ok = (vectorizable_operation (stmt, NULL, NULL)
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|| vectorizable_assignment (stmt, NULL, NULL)
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|| vectorizable_load (stmt, NULL, NULL)
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|| vectorizable_store (stmt, NULL, NULL)
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|| vectorizable_condition (stmt, NULL, NULL));
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if (!ok)
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{
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if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS))
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{
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fprintf (vect_dump,
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"not vectorized: relevant stmt not supported: ");
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print_generic_expr (vect_dump, stmt, TDF_SLIM);
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}
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return false;
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}
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need_to_vectorize = true;
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}
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if (STMT_VINFO_LIVE_P (stmt_info))
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{
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ok = vectorizable_reduction (stmt, NULL, NULL);
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if (ok)
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need_to_vectorize = true;
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else
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ok = vectorizable_live_operation (stmt, NULL, NULL);
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if (!ok)
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{
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if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS))
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{
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fprintf (vect_dump,
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"not vectorized: live stmt not supported: ");
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print_generic_expr (vect_dump, stmt, TDF_SLIM);
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}
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return false;
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}
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}
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} /* stmts in bb */
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} /* bbs */
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/* TODO: Analyze cost. Decide if worth while to vectorize. */
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/* All operations in the loop are either irrelevant (deal with loop
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control, or dead), or only used outside the loop and can be moved
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out of the loop (e.g. invariants, inductions). The loop can be
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optimized away by scalar optimizations. We're better off not
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touching this loop. */
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if (!need_to_vectorize)
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{
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if (vect_print_dump_info (REPORT_DETAILS))
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fprintf (vect_dump,
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"All the computation can be taken out of the loop.");
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if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS))
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fprintf (vect_dump,
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"not vectorized: redundant loop. no profit to vectorize.");
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return false;
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}
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if (LOOP_VINFO_NITERS_KNOWN_P (loop_vinfo)
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&& vect_print_dump_info (REPORT_DETAILS))
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fprintf (vect_dump,
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"vectorization_factor = %d, niters = " HOST_WIDE_INT_PRINT_DEC,
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vectorization_factor, LOOP_VINFO_INT_NITERS (loop_vinfo));
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if (LOOP_VINFO_NITERS_KNOWN_P (loop_vinfo)
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&& LOOP_VINFO_INT_NITERS (loop_vinfo) < vectorization_factor)
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{
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if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS))
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fprintf (vect_dump, "not vectorized: iteration count too small.");
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return false;
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}
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if (!LOOP_VINFO_NITERS_KNOWN_P (loop_vinfo)
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|| LOOP_VINFO_INT_NITERS (loop_vinfo) % vectorization_factor != 0
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|| LOOP_PEELING_FOR_ALIGNMENT (loop_vinfo))
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{
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if (vect_print_dump_info (REPORT_DETAILS))
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fprintf (vect_dump, "epilog loop required.");
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if (!vect_can_advance_ivs_p (loop_vinfo))
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{
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if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS))
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fprintf (vect_dump,
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"not vectorized: can't create epilog loop 1.");
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return false;
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}
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if (!slpeel_can_duplicate_loop_p (loop, loop->single_exit))
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{
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if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS))
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fprintf (vect_dump,
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"not vectorized: can't create epilog loop 2.");
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return false;
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}
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}
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return true;
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}
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|
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/* Function exist_non_indexing_operands_for_use_p
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USE is one of the uses attached to STMT. Check if USE is
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used in STMT for anything other than indexing an array. */
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static bool
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exist_non_indexing_operands_for_use_p (tree use, tree stmt)
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{
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tree operand;
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stmt_vec_info stmt_info = vinfo_for_stmt (stmt);
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|
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/* USE corresponds to some operand in STMT. If there is no data
|
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reference in STMT, then any operand that corresponds to USE
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is not indexing an array. */
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if (!STMT_VINFO_DATA_REF (stmt_info))
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return true;
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|
|
/* STMT has a data_ref. FORNOW this means that its of one of
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the following forms:
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-1- ARRAY_REF = var
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-2- var = ARRAY_REF
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(This should have been verified in analyze_data_refs).
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'var' in the second case corresponds to a def, not a use,
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so USE cannot correspond to any operands that are not used
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for array indexing.
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Therefore, all we need to check is if STMT falls into the
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first case, and whether var corresponds to USE. */
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if (TREE_CODE (TREE_OPERAND (stmt, 0)) == SSA_NAME)
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return false;
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operand = TREE_OPERAND (stmt, 1);
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|
|
if (TREE_CODE (operand) != SSA_NAME)
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return false;
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|
|
if (operand == use)
|
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return true;
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|
|
return false;
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}
|
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|
|
|
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/* Function vect_analyze_scalar_cycles.
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|
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Examine the cross iteration def-use cycles of scalar variables, by
|
|
analyzing the loop (scalar) PHIs; Classify each cycle as one of the
|
|
following: invariant, induction, reduction, unknown.
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Some forms of scalar cycles are not yet supported.
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Example1: reduction: (unsupported yet)
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loop1:
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for (i=0; i<N; i++)
|
|
sum += a[i];
|
|
|
|
Example2: induction: (unsupported yet)
|
|
|
|
loop2:
|
|
for (i=0; i<N; i++)
|
|
a[i] = i;
|
|
|
|
Note: the following loop *is* vectorizable:
|
|
|
|
loop3:
|
|
for (i=0; i<N; i++)
|
|
a[i] = b[i];
|
|
|
|
even though it has a def-use cycle caused by the induction variable i:
|
|
|
|
loop: i_2 = PHI (i_0, i_1)
|
|
a[i_2] = ...;
|
|
i_1 = i_2 + 1;
|
|
GOTO loop;
|
|
|
|
because the def-use cycle in loop3 is considered "not relevant" - i.e.,
|
|
it does not need to be vectorized because it is only used for array
|
|
indexing (see 'mark_stmts_to_be_vectorized'). The def-use cycle in
|
|
loop2 on the other hand is relevant (it is being written to memory).
|
|
*/
|
|
|
|
static void
|
|
vect_analyze_scalar_cycles (loop_vec_info loop_vinfo)
|
|
{
|
|
tree phi;
|
|
struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo);
|
|
basic_block bb = loop->header;
|
|
tree dummy;
|
|
|
|
if (vect_print_dump_info (REPORT_DETAILS))
|
|
fprintf (vect_dump, "=== vect_analyze_scalar_cycles ===");
|
|
|
|
for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
|
|
{
|
|
tree access_fn = NULL;
|
|
tree def = PHI_RESULT (phi);
|
|
stmt_vec_info stmt_vinfo = vinfo_for_stmt (phi);
|
|
tree reduc_stmt;
|
|
|
|
if (vect_print_dump_info (REPORT_DETAILS))
|
|
{
|
|
fprintf (vect_dump, "Analyze phi: ");
|
|
print_generic_expr (vect_dump, phi, TDF_SLIM);
|
|
}
|
|
|
|
/* Skip virtual phi's. The data dependences that are associated with
|
|
virtual defs/uses (i.e., memory accesses) are analyzed elsewhere. */
|
|
|
|
if (!is_gimple_reg (SSA_NAME_VAR (def)))
|
|
{
|
|
if (vect_print_dump_info (REPORT_DETAILS))
|
|
fprintf (vect_dump, "virtual phi. skip.");
|
|
continue;
|
|
}
|
|
|
|
STMT_VINFO_DEF_TYPE (stmt_vinfo) = vect_unknown_def_type;
|
|
|
|
/* Analyze the evolution function. */
|
|
|
|
access_fn = analyze_scalar_evolution (loop, def);
|
|
|
|
if (!access_fn)
|
|
continue;
|
|
|
|
if (vect_print_dump_info (REPORT_DETAILS))
|
|
{
|
|
fprintf (vect_dump, "Access function of PHI: ");
|
|
print_generic_expr (vect_dump, access_fn, TDF_SLIM);
|
|
}
|
|
|
|
if (vect_is_simple_iv_evolution (loop->num, access_fn, &dummy, &dummy))
|
|
{
|
|
if (vect_print_dump_info (REPORT_DETAILS))
|
|
fprintf (vect_dump, "Detected induction.");
|
|
STMT_VINFO_DEF_TYPE (stmt_vinfo) = vect_induction_def;
|
|
continue;
|
|
}
|
|
|
|
/* TODO: handle invariant phis */
|
|
|
|
reduc_stmt = vect_is_simple_reduction (loop, phi);
|
|
if (reduc_stmt)
|
|
{
|
|
if (vect_print_dump_info (REPORT_DETAILS))
|
|
fprintf (vect_dump, "Detected reduction.");
|
|
STMT_VINFO_DEF_TYPE (stmt_vinfo) = vect_reduction_def;
|
|
STMT_VINFO_DEF_TYPE (vinfo_for_stmt (reduc_stmt)) =
|
|
vect_reduction_def;
|
|
}
|
|
else
|
|
if (vect_print_dump_info (REPORT_DETAILS))
|
|
fprintf (vect_dump, "Unknown def-use cycle pattern.");
|
|
|
|
}
|
|
|
|
return;
|
|
}
|
|
|
|
|
|
/* Function vect_analyze_data_ref_dependence.
|
|
|
|
Return TRUE if there (might) exist a dependence between a memory-reference
|
|
DRA and a memory-reference DRB. */
|
|
|
|
static bool
|
|
vect_analyze_data_ref_dependence (struct data_dependence_relation *ddr,
|
|
loop_vec_info loop_vinfo)
|
|
{
|
|
unsigned int i;
|
|
struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo);
|
|
int vectorization_factor = LOOP_VINFO_VECT_FACTOR (loop_vinfo);
|
|
unsigned int loop_depth = 0;
|
|
struct loop *loop_nest = loop;
|
|
struct data_reference *dra = DDR_A (ddr);
|
|
struct data_reference *drb = DDR_B (ddr);
|
|
stmt_vec_info stmtinfo_a = vinfo_for_stmt (DR_STMT (dra));
|
|
stmt_vec_info stmtinfo_b = vinfo_for_stmt (DR_STMT (drb));
|
|
|
|
if (DDR_ARE_DEPENDENT (ddr) == chrec_known)
|
|
return false;
|
|
|
|
if (DDR_ARE_DEPENDENT (ddr) == chrec_dont_know)
|
|
{
|
|
if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS))
|
|
{
|
|
fprintf (vect_dump,
|
|
"not vectorized: can't determine dependence between ");
|
|
print_generic_expr (vect_dump, DR_REF (dra), TDF_SLIM);
|
|
fprintf (vect_dump, " and ");
|
|
print_generic_expr (vect_dump, DR_REF (drb), TDF_SLIM);
|
|
}
|
|
return true;
|
|
}
|
|
|
|
if (DDR_NUM_DIST_VECTS (ddr) == 0)
|
|
{
|
|
if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS))
|
|
{
|
|
fprintf (vect_dump, "not vectorized: bad dist vector for ");
|
|
print_generic_expr (vect_dump, DR_REF (dra), TDF_SLIM);
|
|
fprintf (vect_dump, " and ");
|
|
print_generic_expr (vect_dump, DR_REF (drb), TDF_SLIM);
|
|
}
|
|
return true;
|
|
}
|
|
|
|
/* Find loop depth. */
|
|
while (loop_nest && loop_nest->outer && loop_nest->outer->outer)
|
|
{
|
|
loop_nest = loop_nest->outer;
|
|
loop_depth++;
|
|
}
|
|
|
|
for (i = 0; i < DDR_NUM_DIST_VECTS (ddr); i++)
|
|
{
|
|
int dist = DDR_DIST_VECT (ddr, i)[loop_depth];
|
|
|
|
if (vect_print_dump_info (REPORT_DR_DETAILS))
|
|
fprintf (vect_dump, "dependence distance = %d.", dist);
|
|
|
|
/* Same loop iteration. */
|
|
if (dist % vectorization_factor == 0)
|
|
{
|
|
/* Two references with distance zero have the same alignment. */
|
|
VEC_safe_push (dr_p, heap, STMT_VINFO_SAME_ALIGN_REFS (stmtinfo_a), drb);
|
|
VEC_safe_push (dr_p, heap, STMT_VINFO_SAME_ALIGN_REFS (stmtinfo_b), dra);
|
|
if (vect_print_dump_info (REPORT_ALIGNMENT))
|
|
fprintf (vect_dump, "accesses have the same alignment.");
|
|
if (vect_print_dump_info (REPORT_DR_DETAILS))
|
|
{
|
|
fprintf (vect_dump, "dependence distance modulo vf == 0 between ");
|
|
print_generic_expr (vect_dump, DR_REF (dra), TDF_SLIM);
|
|
fprintf (vect_dump, " and ");
|
|
print_generic_expr (vect_dump, DR_REF (drb), TDF_SLIM);
|
|
}
|
|
continue;
|
|
}
|
|
|
|
if (abs (dist) >= vectorization_factor)
|
|
{
|
|
/* Dependence distance does not create dependence, as far as vectorization
|
|
is concerned, in this case. */
|
|
if (vect_print_dump_info (REPORT_DR_DETAILS))
|
|
fprintf (vect_dump, "dependence distance >= VF.");
|
|
continue;
|
|
}
|
|
|
|
if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS))
|
|
{
|
|
fprintf (vect_dump,
|
|
"not vectorized: possible dependence between data-refs ");
|
|
print_generic_expr (vect_dump, DR_REF (dra), TDF_SLIM);
|
|
fprintf (vect_dump, " and ");
|
|
print_generic_expr (vect_dump, DR_REF (drb), TDF_SLIM);
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
|
|
/* Function vect_analyze_data_ref_dependences.
|
|
|
|
Examine all the data references in the loop, and make sure there do not
|
|
exist any data dependences between them. */
|
|
|
|
static bool
|
|
vect_analyze_data_ref_dependences (loop_vec_info loop_vinfo)
|
|
{
|
|
unsigned int i;
|
|
varray_type ddrs = LOOP_VINFO_DDRS (loop_vinfo);
|
|
|
|
if (vect_print_dump_info (REPORT_DETAILS))
|
|
fprintf (vect_dump, "=== vect_analyze_dependences ===");
|
|
|
|
for (i = 0; i < VARRAY_ACTIVE_SIZE (ddrs); i++)
|
|
{
|
|
struct data_dependence_relation *ddr = VARRAY_GENERIC_PTR (ddrs, i);
|
|
|
|
if (vect_analyze_data_ref_dependence (ddr, loop_vinfo))
|
|
return false;
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
|
|
/* Function vect_compute_data_ref_alignment
|
|
|
|
Compute the misalignment of the data reference DR.
|
|
|
|
Output:
|
|
1. If during the misalignment computation it is found that the data reference
|
|
cannot be vectorized then false is returned.
|
|
2. DR_MISALIGNMENT (DR) is defined.
|
|
|
|
FOR NOW: No analysis is actually performed. Misalignment is calculated
|
|
only for trivial cases. TODO. */
|
|
|
|
static bool
|
|
vect_compute_data_ref_alignment (struct data_reference *dr)
|
|
{
|
|
tree stmt = DR_STMT (dr);
|
|
stmt_vec_info stmt_info = vinfo_for_stmt (stmt);
|
|
tree ref = DR_REF (dr);
|
|
tree vectype;
|
|
tree base, base_addr;
|
|
bool base_aligned;
|
|
tree misalign;
|
|
tree aligned_to, alignment;
|
|
|
|
if (vect_print_dump_info (REPORT_DETAILS))
|
|
fprintf (vect_dump, "vect_compute_data_ref_alignment:");
|
|
|
|
/* Initialize misalignment to unknown. */
|
|
DR_MISALIGNMENT (dr) = -1;
|
|
|
|
misalign = DR_OFFSET_MISALIGNMENT (dr);
|
|
aligned_to = DR_ALIGNED_TO (dr);
|
|
base_addr = DR_BASE_ADDRESS (dr);
|
|
base = build_fold_indirect_ref (base_addr);
|
|
vectype = STMT_VINFO_VECTYPE (stmt_info);
|
|
alignment = ssize_int (TYPE_ALIGN (vectype)/BITS_PER_UNIT);
|
|
|
|
if ((aligned_to && tree_int_cst_compare (aligned_to, alignment) < 0)
|
|
|| !misalign)
|
|
{
|
|
if (vect_print_dump_info (REPORT_DETAILS))
|
|
{
|
|
fprintf (vect_dump, "Unknown alignment for access: ");
|
|
print_generic_expr (vect_dump, base, TDF_SLIM);
|
|
}
|
|
return true;
|
|
}
|
|
|
|
if ((DECL_P (base)
|
|
&& tree_int_cst_compare (ssize_int (DECL_ALIGN_UNIT (base)),
|
|
alignment) >= 0)
|
|
|| (TREE_CODE (base_addr) == SSA_NAME
|
|
&& tree_int_cst_compare (ssize_int (TYPE_ALIGN_UNIT (TREE_TYPE (
|
|
TREE_TYPE (base_addr)))),
|
|
alignment) >= 0))
|
|
base_aligned = true;
|
|
else
|
|
base_aligned = false;
|
|
|
|
if (!base_aligned)
|
|
{
|
|
if (!vect_can_force_dr_alignment_p (base, TYPE_ALIGN (vectype)))
|
|
{
|
|
if (vect_print_dump_info (REPORT_DETAILS))
|
|
{
|
|
fprintf (vect_dump, "can't force alignment of ref: ");
|
|
print_generic_expr (vect_dump, ref, TDF_SLIM);
|
|
}
|
|
return true;
|
|
}
|
|
|
|
/* Force the alignment of the decl.
|
|
NOTE: This is the only change to the code we make during
|
|
the analysis phase, before deciding to vectorize the loop. */
|
|
if (vect_print_dump_info (REPORT_DETAILS))
|
|
fprintf (vect_dump, "force alignment");
|
|
DECL_ALIGN (base) = TYPE_ALIGN (vectype);
|
|
DECL_USER_ALIGN (base) = 1;
|
|
}
|
|
|
|
/* At this point we assume that the base is aligned. */
|
|
gcc_assert (base_aligned
|
|
|| (TREE_CODE (base) == VAR_DECL
|
|
&& DECL_ALIGN (base) >= TYPE_ALIGN (vectype)));
|
|
|
|
/* Modulo alignment. */
|
|
misalign = size_binop (TRUNC_MOD_EXPR, misalign, alignment);
|
|
|
|
if (!host_integerp (misalign, 1))
|
|
{
|
|
/* Negative or overflowed misalignment value. */
|
|
if (vect_print_dump_info (REPORT_DETAILS))
|
|
fprintf (vect_dump, "unexpected misalign value");
|
|
return false;
|
|
}
|
|
|
|
DR_MISALIGNMENT (dr) = TREE_INT_CST_LOW (misalign);
|
|
|
|
if (vect_print_dump_info (REPORT_DETAILS))
|
|
{
|
|
fprintf (vect_dump, "misalign = %d bytes of ref ", DR_MISALIGNMENT (dr));
|
|
print_generic_expr (vect_dump, ref, TDF_SLIM);
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
|
|
/* Function vect_compute_data_refs_alignment
|
|
|
|
Compute the misalignment of data references in the loop.
|
|
Return FALSE if a data reference is found that cannot be vectorized. */
|
|
|
|
static bool
|
|
vect_compute_data_refs_alignment (loop_vec_info loop_vinfo)
|
|
{
|
|
varray_type datarefs = LOOP_VINFO_DATAREFS (loop_vinfo);
|
|
unsigned int i;
|
|
|
|
for (i = 0; i < VARRAY_ACTIVE_SIZE (datarefs); i++)
|
|
{
|
|
struct data_reference *dr = VARRAY_GENERIC_PTR (datarefs, i);
|
|
if (!vect_compute_data_ref_alignment (dr))
|
|
return false;
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
|
|
/* Function vect_update_misalignment_for_peel
|
|
|
|
DR - the data reference whose misalignment is to be adjusted.
|
|
DR_PEEL - the data reference whose misalignment is being made
|
|
zero in the vector loop by the peel.
|
|
NPEEL - the number of iterations in the peel loop if the misalignment
|
|
of DR_PEEL is known at compile time. */
|
|
|
|
static void
|
|
vect_update_misalignment_for_peel (struct data_reference *dr,
|
|
struct data_reference *dr_peel, int npeel)
|
|
{
|
|
unsigned int i;
|
|
int drsize;
|
|
VEC(dr_p,heap) *same_align_drs;
|
|
struct data_reference *current_dr;
|
|
|
|
if (known_alignment_for_access_p (dr)
|
|
&& DR_MISALIGNMENT (dr) == DR_MISALIGNMENT (dr_peel))
|
|
{
|
|
DR_MISALIGNMENT (dr) = 0;
|
|
return;
|
|
}
|
|
|
|
/* It can be assumed that the data refs with the same alignment as dr_peel
|
|
are aligned in the vector loop. */
|
|
same_align_drs
|
|
= STMT_VINFO_SAME_ALIGN_REFS (vinfo_for_stmt (DR_STMT (dr_peel)));
|
|
for (i = 0; VEC_iterate (dr_p, same_align_drs, i, current_dr); i++)
|
|
{
|
|
if (current_dr != dr)
|
|
continue;
|
|
gcc_assert (DR_MISALIGNMENT (dr) == DR_MISALIGNMENT (dr_peel));
|
|
DR_MISALIGNMENT (dr) = 0;
|
|
return;
|
|
}
|
|
|
|
if (known_alignment_for_access_p (dr)
|
|
&& known_alignment_for_access_p (dr_peel))
|
|
{
|
|
drsize = GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (DR_REF (dr))));
|
|
DR_MISALIGNMENT (dr) += npeel * drsize;
|
|
DR_MISALIGNMENT (dr) %= UNITS_PER_SIMD_WORD;
|
|
return;
|
|
}
|
|
|
|
DR_MISALIGNMENT (dr) = -1;
|
|
}
|
|
|
|
|
|
/* Function vect_verify_datarefs_alignment
|
|
|
|
Return TRUE if all data references in the loop can be
|
|
handled with respect to alignment. */
|
|
|
|
static bool
|
|
vect_verify_datarefs_alignment (loop_vec_info loop_vinfo)
|
|
{
|
|
varray_type datarefs = LOOP_VINFO_DATAREFS (loop_vinfo);
|
|
enum dr_alignment_support supportable_dr_alignment;
|
|
unsigned int i;
|
|
|
|
for (i = 0; i < VARRAY_ACTIVE_SIZE (datarefs); i++)
|
|
{
|
|
struct data_reference *dr = VARRAY_GENERIC_PTR (datarefs, i);
|
|
supportable_dr_alignment = vect_supportable_dr_alignment (dr);
|
|
if (!supportable_dr_alignment)
|
|
{
|
|
if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS))
|
|
{
|
|
if (DR_IS_READ (dr))
|
|
fprintf (vect_dump,
|
|
"not vectorized: unsupported unaligned load.");
|
|
else
|
|
fprintf (vect_dump,
|
|
"not vectorized: unsupported unaligned store.");
|
|
}
|
|
return false;
|
|
}
|
|
if (supportable_dr_alignment != dr_aligned
|
|
&& vect_print_dump_info (REPORT_ALIGNMENT))
|
|
fprintf (vect_dump, "Vectorizing an unaligned access.");
|
|
}
|
|
return true;
|
|
}
|
|
|
|
|
|
/* Function vect_enhance_data_refs_alignment
|
|
|
|
This pass will use loop versioning and loop peeling in order to enhance
|
|
the alignment of data references in the loop.
|
|
|
|
FOR NOW: we assume that whatever versioning/peeling takes place, only the
|
|
original loop is to be vectorized; Any other loops that are created by
|
|
the transformations performed in this pass - are not supposed to be
|
|
vectorized. This restriction will be relaxed.
|
|
|
|
This pass will require a cost model to guide it whether to apply peeling
|
|
or versioning or a combination of the two. For example, the scheme that
|
|
intel uses when given a loop with several memory accesses, is as follows:
|
|
choose one memory access ('p') which alignment you want to force by doing
|
|
peeling. Then, either (1) generate a loop in which 'p' is aligned and all
|
|
other accesses are not necessarily aligned, or (2) use loop versioning to
|
|
generate one loop in which all accesses are aligned, and another loop in
|
|
which only 'p' is necessarily aligned.
|
|
|
|
("Automatic Intra-Register Vectorization for the Intel Architecture",
|
|
Aart J.C. Bik, Milind Girkar, Paul M. Grey and Ximmin Tian, International
|
|
Journal of Parallel Programming, Vol. 30, No. 2, April 2002.)
|
|
|
|
Devising a cost model is the most critical aspect of this work. It will
|
|
guide us on which access to peel for, whether to use loop versioning, how
|
|
many versions to create, etc. The cost model will probably consist of
|
|
generic considerations as well as target specific considerations (on
|
|
powerpc for example, misaligned stores are more painful than misaligned
|
|
loads).
|
|
|
|
Here are the general steps involved in alignment enhancements:
|
|
|
|
-- original loop, before alignment analysis:
|
|
for (i=0; i<N; i++){
|
|
x = q[i]; # DR_MISALIGNMENT(q) = unknown
|
|
p[i] = y; # DR_MISALIGNMENT(p) = unknown
|
|
}
|
|
|
|
-- After vect_compute_data_refs_alignment:
|
|
for (i=0; i<N; i++){
|
|
x = q[i]; # DR_MISALIGNMENT(q) = 3
|
|
p[i] = y; # DR_MISALIGNMENT(p) = unknown
|
|
}
|
|
|
|
-- Possibility 1: we do loop versioning:
|
|
if (p is aligned) {
|
|
for (i=0; i<N; i++){ # loop 1A
|
|
x = q[i]; # DR_MISALIGNMENT(q) = 3
|
|
p[i] = y; # DR_MISALIGNMENT(p) = 0
|
|
}
|
|
}
|
|
else {
|
|
for (i=0; i<N; i++){ # loop 1B
|
|
x = q[i]; # DR_MISALIGNMENT(q) = 3
|
|
p[i] = y; # DR_MISALIGNMENT(p) = unaligned
|
|
}
|
|
}
|
|
|
|
-- Possibility 2: we do loop peeling:
|
|
for (i = 0; i < 3; i++){ # (scalar loop, not to be vectorized).
|
|
x = q[i];
|
|
p[i] = y;
|
|
}
|
|
for (i = 3; i < N; i++){ # loop 2A
|
|
x = q[i]; # DR_MISALIGNMENT(q) = 0
|
|
p[i] = y; # DR_MISALIGNMENT(p) = unknown
|
|
}
|
|
|
|
-- Possibility 3: combination of loop peeling and versioning:
|
|
for (i = 0; i < 3; i++){ # (scalar loop, not to be vectorized).
|
|
x = q[i];
|
|
p[i] = y;
|
|
}
|
|
if (p is aligned) {
|
|
for (i = 3; i<N; i++){ # loop 3A
|
|
x = q[i]; # DR_MISALIGNMENT(q) = 0
|
|
p[i] = y; # DR_MISALIGNMENT(p) = 0
|
|
}
|
|
}
|
|
else {
|
|
for (i = 3; i<N; i++){ # loop 3B
|
|
x = q[i]; # DR_MISALIGNMENT(q) = 0
|
|
p[i] = y; # DR_MISALIGNMENT(p) = unaligned
|
|
}
|
|
}
|
|
|
|
These loops are later passed to loop_transform to be vectorized. The
|
|
vectorizer will use the alignment information to guide the transformation
|
|
(whether to generate regular loads/stores, or with special handling for
|
|
misalignment). */
|
|
|
|
static bool
|
|
vect_enhance_data_refs_alignment (loop_vec_info loop_vinfo)
|
|
{
|
|
varray_type datarefs = LOOP_VINFO_DATAREFS (loop_vinfo);
|
|
enum dr_alignment_support supportable_dr_alignment;
|
|
struct data_reference *dr0 = NULL;
|
|
struct data_reference *dr;
|
|
unsigned int i;
|
|
bool do_peeling = false;
|
|
bool do_versioning = false;
|
|
bool stat;
|
|
|
|
/* While cost model enhancements are expected in the future, the high level
|
|
view of the code at this time is as follows:
|
|
|
|
A) If there is a misaligned write then see if peeling to align this write
|
|
can make all data references satisfy vect_supportable_dr_alignment.
|
|
If so, update data structures as needed and return true. Note that
|
|
at this time vect_supportable_dr_alignment is known to return false
|
|
for a a misaligned write.
|
|
|
|
B) If peeling wasn't possible and there is a data reference with an
|
|
unknown misalignment that does not satisfy vect_supportable_dr_alignment
|
|
then see if loop versioning checks can be used to make all data
|
|
references satisfy vect_supportable_dr_alignment. If so, update
|
|
data structures as needed and return true.
|
|
|
|
C) If neither peeling nor versioning were successful then return false if
|
|
any data reference does not satisfy vect_supportable_dr_alignment.
|
|
|
|
D) Return true (all data references satisfy vect_supportable_dr_alignment).
|
|
|
|
Note, Possibility 3 above (which is peeling and versioning together) is not
|
|
being done at this time. */
|
|
|
|
/* (1) Peeling to force alignment. */
|
|
|
|
/* (1.1) Decide whether to perform peeling, and how many iterations to peel:
|
|
Considerations:
|
|
+ How many accesses will become aligned due to the peeling
|
|
- How many accesses will become unaligned due to the peeling,
|
|
and the cost of misaligned accesses.
|
|
- The cost of peeling (the extra runtime checks, the increase
|
|
in code size).
|
|
|
|
The scheme we use FORNOW: peel to force the alignment of the first
|
|
misaligned store in the loop.
|
|
Rationale: misaligned stores are not yet supported.
|
|
|
|
TODO: Use a cost model. */
|
|
|
|
for (i = 0; i < VARRAY_ACTIVE_SIZE (datarefs); i++)
|
|
{
|
|
dr = VARRAY_GENERIC_PTR (datarefs, i);
|
|
if (!DR_IS_READ (dr) && !aligned_access_p (dr))
|
|
{
|
|
dr0 = dr;
|
|
do_peeling = true;
|
|
break;
|
|
}
|
|
}
|
|
|
|
/* Often peeling for alignment will require peeling for loop-bound, which in
|
|
turn requires that we know how to adjust the loop ivs after the loop. */
|
|
if (!vect_can_advance_ivs_p (loop_vinfo))
|
|
do_peeling = false;
|
|
|
|
if (do_peeling)
|
|
{
|
|
int mis;
|
|
int npeel = 0;
|
|
|
|
if (known_alignment_for_access_p (dr0))
|
|
{
|
|
/* Since it's known at compile time, compute the number of iterations
|
|
in the peeled loop (the peeling factor) for use in updating
|
|
DR_MISALIGNMENT values. The peeling factor is the vectorization
|
|
factor minus the misalignment as an element count. */
|
|
mis = DR_MISALIGNMENT (dr0);
|
|
mis /= GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (DR_REF (dr0))));
|
|
npeel = LOOP_VINFO_VECT_FACTOR (loop_vinfo) - mis;
|
|
}
|
|
|
|
/* Ensure that all data refs can be vectorized after the peel. */
|
|
for (i = 0; i < VARRAY_ACTIVE_SIZE (datarefs); i++)
|
|
{
|
|
int save_misalignment;
|
|
|
|
dr = VARRAY_GENERIC_PTR (datarefs, i);
|
|
if (dr == dr0)
|
|
continue;
|
|
save_misalignment = DR_MISALIGNMENT (dr);
|
|
vect_update_misalignment_for_peel (dr, dr0, npeel);
|
|
supportable_dr_alignment = vect_supportable_dr_alignment (dr);
|
|
DR_MISALIGNMENT (dr) = save_misalignment;
|
|
|
|
if (!supportable_dr_alignment)
|
|
{
|
|
do_peeling = false;
|
|
break;
|
|
}
|
|
}
|
|
|
|
if (do_peeling)
|
|
{
|
|
/* (1.2) Update the DR_MISALIGNMENT of each data reference DR_i.
|
|
If the misalignment of DR_i is identical to that of dr0 then set
|
|
DR_MISALIGNMENT (DR_i) to zero. If the misalignment of DR_i and
|
|
dr0 are known at compile time then increment DR_MISALIGNMENT (DR_i)
|
|
by the peeling factor times the element size of DR_i (MOD the
|
|
vectorization factor times the size). Otherwise, the
|
|
misalignment of DR_i must be set to unknown. */
|
|
for (i = 0; i < VARRAY_ACTIVE_SIZE (datarefs); i++)
|
|
{
|
|
dr = VARRAY_GENERIC_PTR (datarefs, i);
|
|
if (dr == dr0)
|
|
continue;
|
|
vect_update_misalignment_for_peel (dr, dr0, npeel);
|
|
}
|
|
|
|
LOOP_VINFO_UNALIGNED_DR (loop_vinfo) = dr0;
|
|
LOOP_PEELING_FOR_ALIGNMENT (loop_vinfo) = DR_MISALIGNMENT (dr0);
|
|
DR_MISALIGNMENT (dr0) = 0;
|
|
if (vect_print_dump_info (REPORT_ALIGNMENT))
|
|
fprintf (vect_dump, "Alignment of access forced using peeling.");
|
|
|
|
if (vect_print_dump_info (REPORT_DETAILS))
|
|
fprintf (vect_dump, "Peeling for alignment will be applied.");
|
|
|
|
stat = vect_verify_datarefs_alignment (loop_vinfo);
|
|
gcc_assert (stat);
|
|
return stat;
|
|
}
|
|
}
|
|
|
|
|
|
/* (2) Versioning to force alignment. */
|
|
|
|
/* Try versioning if:
|
|
1) flag_tree_vect_loop_version is TRUE
|
|
2) optimize_size is FALSE
|
|
3) there is at least one unsupported misaligned data ref with an unknown
|
|
misalignment, and
|
|
4) all misaligned data refs with a known misalignment are supported, and
|
|
5) the number of runtime alignment checks is within reason. */
|
|
|
|
do_versioning = flag_tree_vect_loop_version && (!optimize_size);
|
|
|
|
if (do_versioning)
|
|
{
|
|
for (i = 0; i < VARRAY_ACTIVE_SIZE (datarefs); i++)
|
|
{
|
|
dr = VARRAY_GENERIC_PTR (datarefs, i);
|
|
|
|
if (aligned_access_p (dr))
|
|
continue;
|
|
|
|
supportable_dr_alignment = vect_supportable_dr_alignment (dr);
|
|
|
|
if (!supportable_dr_alignment)
|
|
{
|
|
tree stmt;
|
|
int mask;
|
|
tree vectype;
|
|
|
|
if (known_alignment_for_access_p (dr)
|
|
|| VEC_length (tree,
|
|
LOOP_VINFO_MAY_MISALIGN_STMTS (loop_vinfo))
|
|
>= (unsigned) PARAM_VALUE (PARAM_VECT_MAX_VERSION_CHECKS))
|
|
{
|
|
do_versioning = false;
|
|
break;
|
|
}
|
|
|
|
stmt = DR_STMT (dr);
|
|
vectype = STMT_VINFO_VECTYPE (vinfo_for_stmt (stmt));
|
|
gcc_assert (vectype);
|
|
|
|
/* The rightmost bits of an aligned address must be zeros.
|
|
Construct the mask needed for this test. For example,
|
|
GET_MODE_SIZE for the vector mode V4SI is 16 bytes so the
|
|
mask must be 15 = 0xf. */
|
|
mask = GET_MODE_SIZE (TYPE_MODE (vectype)) - 1;
|
|
|
|
/* FORNOW: use the same mask to test all potentially unaligned
|
|
references in the loop. The vectorizer currently supports
|
|
a single vector size, see the reference to
|
|
GET_MODE_NUNITS (TYPE_MODE (vectype)) where the
|
|
vectorization factor is computed. */
|
|
gcc_assert (!LOOP_VINFO_PTR_MASK (loop_vinfo)
|
|
|| LOOP_VINFO_PTR_MASK (loop_vinfo) == mask);
|
|
LOOP_VINFO_PTR_MASK (loop_vinfo) = mask;
|
|
VEC_safe_push (tree, heap,
|
|
LOOP_VINFO_MAY_MISALIGN_STMTS (loop_vinfo),
|
|
DR_STMT (dr));
|
|
}
|
|
}
|
|
|
|
/* Versioning requires at least one misaligned data reference. */
|
|
if (VEC_length (tree, LOOP_VINFO_MAY_MISALIGN_STMTS (loop_vinfo)) == 0)
|
|
do_versioning = false;
|
|
else if (!do_versioning)
|
|
VEC_truncate (tree, LOOP_VINFO_MAY_MISALIGN_STMTS (loop_vinfo), 0);
|
|
}
|
|
|
|
if (do_versioning)
|
|
{
|
|
VEC(tree,heap) *may_misalign_stmts
|
|
= LOOP_VINFO_MAY_MISALIGN_STMTS (loop_vinfo);
|
|
tree stmt;
|
|
|
|
/* It can now be assumed that the data references in the statements
|
|
in LOOP_VINFO_MAY_MISALIGN_STMTS will be aligned in the version
|
|
of the loop being vectorized. */
|
|
for (i = 0; VEC_iterate (tree, may_misalign_stmts, i, stmt); i++)
|
|
{
|
|
stmt_vec_info stmt_info = vinfo_for_stmt (stmt);
|
|
dr = STMT_VINFO_DATA_REF (stmt_info);
|
|
DR_MISALIGNMENT (dr) = 0;
|
|
if (vect_print_dump_info (REPORT_ALIGNMENT))
|
|
fprintf (vect_dump, "Alignment of access forced using versioning.");
|
|
}
|
|
|
|
if (vect_print_dump_info (REPORT_DETAILS))
|
|
fprintf (vect_dump, "Versioning for alignment will be applied.");
|
|
|
|
/* Peeling and versioning can't be done together at this time. */
|
|
gcc_assert (! (do_peeling && do_versioning));
|
|
|
|
stat = vect_verify_datarefs_alignment (loop_vinfo);
|
|
gcc_assert (stat);
|
|
return stat;
|
|
}
|
|
|
|
/* This point is reached if neither peeling nor versioning is being done. */
|
|
gcc_assert (! (do_peeling || do_versioning));
|
|
|
|
stat = vect_verify_datarefs_alignment (loop_vinfo);
|
|
return stat;
|
|
}
|
|
|
|
|
|
/* Function vect_analyze_data_refs_alignment
|
|
|
|
Analyze the alignment of the data-references in the loop.
|
|
Return FALSE if a data reference is found that cannot be vectorized. */
|
|
|
|
static bool
|
|
vect_analyze_data_refs_alignment (loop_vec_info loop_vinfo)
|
|
{
|
|
if (vect_print_dump_info (REPORT_DETAILS))
|
|
fprintf (vect_dump, "=== vect_analyze_data_refs_alignment ===");
|
|
|
|
if (!vect_compute_data_refs_alignment (loop_vinfo))
|
|
{
|
|
if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS))
|
|
fprintf (vect_dump,
|
|
"not vectorized: can't calculate alignment for data ref.");
|
|
return false;
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
|
|
/* Function vect_analyze_data_ref_access.
|
|
|
|
Analyze the access pattern of the data-reference DR. For now, a data access
|
|
has to be consecutive to be considered vectorizable. */
|
|
|
|
static bool
|
|
vect_analyze_data_ref_access (struct data_reference *dr)
|
|
{
|
|
tree step = DR_STEP (dr);
|
|
tree scalar_type = TREE_TYPE (DR_REF (dr));
|
|
|
|
if (!step || tree_int_cst_compare (step, TYPE_SIZE_UNIT (scalar_type)))
|
|
{
|
|
if (vect_print_dump_info (REPORT_DETAILS))
|
|
fprintf (vect_dump, "not consecutive access");
|
|
return false;
|
|
}
|
|
return true;
|
|
}
|
|
|
|
|
|
/* Function vect_analyze_data_ref_accesses.
|
|
|
|
Analyze the access pattern of all the data references in the loop.
|
|
|
|
FORNOW: the only access pattern that is considered vectorizable is a
|
|
simple step 1 (consecutive) access.
|
|
|
|
FORNOW: handle only arrays and pointer accesses. */
|
|
|
|
static bool
|
|
vect_analyze_data_ref_accesses (loop_vec_info loop_vinfo)
|
|
{
|
|
unsigned int i;
|
|
varray_type datarefs = LOOP_VINFO_DATAREFS (loop_vinfo);
|
|
|
|
if (vect_print_dump_info (REPORT_DETAILS))
|
|
fprintf (vect_dump, "=== vect_analyze_data_ref_accesses ===");
|
|
|
|
for (i = 0; i < VARRAY_ACTIVE_SIZE (datarefs); i++)
|
|
{
|
|
struct data_reference *dr = VARRAY_GENERIC_PTR (datarefs, i);
|
|
if (!vect_analyze_data_ref_access (dr))
|
|
{
|
|
if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS))
|
|
fprintf (vect_dump, "not vectorized: complicated access pattern.");
|
|
return false;
|
|
}
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
|
|
/* Function vect_analyze_data_refs.
|
|
|
|
Find all the data references in the loop.
|
|
|
|
The general structure of the analysis of data refs in the vectorizer is as
|
|
follows:
|
|
1- vect_analyze_data_refs(loop): call compute_data_dependences_for_loop to
|
|
find and analyze all data-refs in the loop and their dependences.
|
|
2- vect_analyze_dependences(): apply dependence testing using ddrs.
|
|
3- vect_analyze_drs_alignment(): check that ref_stmt.alignment is ok.
|
|
4- vect_analyze_drs_access(): check that ref_stmt.step is ok.
|
|
|
|
*/
|
|
|
|
static bool
|
|
vect_analyze_data_refs (loop_vec_info loop_vinfo)
|
|
{
|
|
struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo);
|
|
unsigned int i;
|
|
varray_type datarefs;
|
|
tree scalar_type;
|
|
|
|
if (vect_print_dump_info (REPORT_DETAILS))
|
|
fprintf (vect_dump, "=== vect_analyze_data_refs ===");
|
|
|
|
compute_data_dependences_for_loop (loop, false,
|
|
&(LOOP_VINFO_DATAREFS (loop_vinfo)),
|
|
&(LOOP_VINFO_DDRS (loop_vinfo)));
|
|
|
|
/* Go through the data-refs, check that the analysis succeeded. Update pointer
|
|
from stmt_vec_info struct to DR and vectype. */
|
|
datarefs = LOOP_VINFO_DATAREFS (loop_vinfo);
|
|
for (i = 0; i < VARRAY_ACTIVE_SIZE (datarefs); i++)
|
|
{
|
|
struct data_reference *dr = VARRAY_GENERIC_PTR (datarefs, i);
|
|
tree stmt;
|
|
stmt_vec_info stmt_info;
|
|
|
|
if (!dr || !DR_REF (dr))
|
|
{
|
|
if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS))
|
|
fprintf (vect_dump, "not vectorized: unhandled data-ref ");
|
|
return false;
|
|
}
|
|
|
|
/* Update DR field in stmt_vec_info struct. */
|
|
stmt = DR_STMT (dr);
|
|
stmt_info = vinfo_for_stmt (stmt);
|
|
|
|
if (STMT_VINFO_DATA_REF (stmt_info))
|
|
{
|
|
if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS))
|
|
{
|
|
fprintf (vect_dump,
|
|
"not vectorized: more than one data ref in stmt: ");
|
|
print_generic_expr (vect_dump, stmt, TDF_SLIM);
|
|
}
|
|
return false;
|
|
}
|
|
STMT_VINFO_DATA_REF (stmt_info) = dr;
|
|
|
|
/* Check that analysis of the data-ref succeeded. */
|
|
if (!DR_BASE_ADDRESS (dr) || !DR_OFFSET (dr) || !DR_INIT (dr)
|
|
|| !DR_STEP (dr))
|
|
{
|
|
if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS))
|
|
{
|
|
fprintf (vect_dump, "not vectorized: data ref analysis failed ");
|
|
print_generic_expr (vect_dump, stmt, TDF_SLIM);
|
|
}
|
|
return false;
|
|
}
|
|
if (!DR_MEMTAG (dr))
|
|
{
|
|
if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS))
|
|
{
|
|
fprintf (vect_dump, "not vectorized: no memory tag for ");
|
|
print_generic_expr (vect_dump, DR_REF (dr), TDF_SLIM);
|
|
}
|
|
return false;
|
|
}
|
|
|
|
/* Set vectype for STMT. */
|
|
scalar_type = TREE_TYPE (DR_REF (dr));
|
|
STMT_VINFO_VECTYPE (stmt_info) =
|
|
get_vectype_for_scalar_type (scalar_type);
|
|
if (!STMT_VINFO_VECTYPE (stmt_info))
|
|
{
|
|
if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS))
|
|
{
|
|
fprintf (vect_dump,
|
|
"not vectorized: no vectype for stmt: ");
|
|
print_generic_expr (vect_dump, stmt, TDF_SLIM);
|
|
fprintf (vect_dump, " scalar_type: ");
|
|
print_generic_expr (vect_dump, scalar_type, TDF_DETAILS);
|
|
}
|
|
return false;
|
|
}
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
|
|
/* Utility functions used by vect_mark_stmts_to_be_vectorized. */
|
|
|
|
/* Function vect_mark_relevant.
|
|
|
|
Mark STMT as "relevant for vectorization" and add it to WORKLIST. */
|
|
|
|
static void
|
|
vect_mark_relevant (VEC(tree,heap) **worklist, tree stmt,
|
|
bool relevant_p, bool live_p)
|
|
{
|
|
stmt_vec_info stmt_info = vinfo_for_stmt (stmt);
|
|
bool save_relevant_p = STMT_VINFO_RELEVANT_P (stmt_info);
|
|
bool save_live_p = STMT_VINFO_LIVE_P (stmt_info);
|
|
|
|
if (vect_print_dump_info (REPORT_DETAILS))
|
|
fprintf (vect_dump, "mark relevant %d, live %d.",relevant_p, live_p);
|
|
|
|
STMT_VINFO_LIVE_P (stmt_info) |= live_p;
|
|
STMT_VINFO_RELEVANT_P (stmt_info) |= relevant_p;
|
|
|
|
if (TREE_CODE (stmt) == PHI_NODE)
|
|
/* Don't put phi-nodes in the worklist. Phis that are marked relevant
|
|
or live will fail vectorization later on. */
|
|
return;
|
|
|
|
if (STMT_VINFO_RELEVANT_P (stmt_info) == save_relevant_p
|
|
&& STMT_VINFO_LIVE_P (stmt_info) == save_live_p)
|
|
{
|
|
if (vect_print_dump_info (REPORT_DETAILS))
|
|
fprintf (vect_dump, "already marked relevant/live.");
|
|
return;
|
|
}
|
|
|
|
VEC_safe_push (tree, heap, *worklist, stmt);
|
|
}
|
|
|
|
|
|
/* Function vect_stmt_relevant_p.
|
|
|
|
Return true if STMT in loop that is represented by LOOP_VINFO is
|
|
"relevant for vectorization".
|
|
|
|
A stmt is considered "relevant for vectorization" if:
|
|
- it has uses outside the loop.
|
|
- it has vdefs (it alters memory).
|
|
- control stmts in the loop (except for the exit condition).
|
|
|
|
CHECKME: what other side effects would the vectorizer allow? */
|
|
|
|
static bool
|
|
vect_stmt_relevant_p (tree stmt, loop_vec_info loop_vinfo,
|
|
bool *relevant_p, bool *live_p)
|
|
{
|
|
struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo);
|
|
ssa_op_iter op_iter;
|
|
imm_use_iterator imm_iter;
|
|
use_operand_p use_p;
|
|
def_operand_p def_p;
|
|
|
|
*relevant_p = false;
|
|
*live_p = false;
|
|
|
|
/* cond stmt other than loop exit cond. */
|
|
if (is_ctrl_stmt (stmt) && (stmt != LOOP_VINFO_EXIT_COND (loop_vinfo)))
|
|
*relevant_p = true;
|
|
|
|
/* changing memory. */
|
|
if (TREE_CODE (stmt) != PHI_NODE)
|
|
if (!ZERO_SSA_OPERANDS (stmt, SSA_OP_VIRTUAL_DEFS))
|
|
{
|
|
if (vect_print_dump_info (REPORT_DETAILS))
|
|
fprintf (vect_dump, "vec_stmt_relevant_p: stmt has vdefs.");
|
|
*relevant_p = true;
|
|
}
|
|
|
|
/* uses outside the loop. */
|
|
FOR_EACH_PHI_OR_STMT_DEF (def_p, stmt, op_iter, SSA_OP_DEF)
|
|
{
|
|
FOR_EACH_IMM_USE_FAST (use_p, imm_iter, DEF_FROM_PTR (def_p))
|
|
{
|
|
basic_block bb = bb_for_stmt (USE_STMT (use_p));
|
|
if (!flow_bb_inside_loop_p (loop, bb))
|
|
{
|
|
if (vect_print_dump_info (REPORT_DETAILS))
|
|
fprintf (vect_dump, "vec_stmt_relevant_p: used out of loop.");
|
|
|
|
/* We expect all such uses to be in the loop exit phis
|
|
(because of loop closed form) */
|
|
gcc_assert (TREE_CODE (USE_STMT (use_p)) == PHI_NODE);
|
|
gcc_assert (bb == loop->single_exit->dest);
|
|
|
|
*live_p = true;
|
|
}
|
|
}
|
|
}
|
|
|
|
return (*live_p || *relevant_p);
|
|
}
|
|
|
|
|
|
/* Function vect_mark_stmts_to_be_vectorized.
|
|
|
|
Not all stmts in the loop need to be vectorized. For example:
|
|
|
|
for i...
|
|
for j...
|
|
1. T0 = i + j
|
|
2. T1 = a[T0]
|
|
|
|
3. j = j + 1
|
|
|
|
Stmt 1 and 3 do not need to be vectorized, because loop control and
|
|
addressing of vectorized data-refs are handled differently.
|
|
|
|
This pass detects such stmts. */
|
|
|
|
static bool
|
|
vect_mark_stmts_to_be_vectorized (loop_vec_info loop_vinfo)
|
|
{
|
|
VEC(tree,heap) *worklist;
|
|
struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo);
|
|
basic_block *bbs = LOOP_VINFO_BBS (loop_vinfo);
|
|
unsigned int nbbs = loop->num_nodes;
|
|
block_stmt_iterator si;
|
|
tree stmt, use;
|
|
stmt_ann_t ann;
|
|
ssa_op_iter iter;
|
|
unsigned int i;
|
|
stmt_vec_info stmt_vinfo;
|
|
basic_block bb;
|
|
tree phi;
|
|
bool relevant_p, live_p;
|
|
tree def, def_stmt;
|
|
enum vect_def_type dt;
|
|
|
|
if (vect_print_dump_info (REPORT_DETAILS))
|
|
fprintf (vect_dump, "=== vect_mark_stmts_to_be_vectorized ===");
|
|
|
|
worklist = VEC_alloc (tree, heap, 64);
|
|
|
|
/* 1. Init worklist. */
|
|
|
|
bb = loop->header;
|
|
for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
|
|
{
|
|
if (vect_print_dump_info (REPORT_DETAILS))
|
|
{
|
|
fprintf (vect_dump, "init: phi relevant? ");
|
|
print_generic_expr (vect_dump, phi, TDF_SLIM);
|
|
}
|
|
|
|
if (vect_stmt_relevant_p (phi, loop_vinfo, &relevant_p, &live_p))
|
|
vect_mark_relevant (&worklist, phi, relevant_p, live_p);
|
|
}
|
|
|
|
for (i = 0; i < nbbs; i++)
|
|
{
|
|
bb = bbs[i];
|
|
for (si = bsi_start (bb); !bsi_end_p (si); bsi_next (&si))
|
|
{
|
|
stmt = bsi_stmt (si);
|
|
|
|
if (vect_print_dump_info (REPORT_DETAILS))
|
|
{
|
|
fprintf (vect_dump, "init: stmt relevant? ");
|
|
print_generic_expr (vect_dump, stmt, TDF_SLIM);
|
|
}
|
|
|
|
if (vect_stmt_relevant_p (stmt, loop_vinfo, &relevant_p, &live_p))
|
|
vect_mark_relevant (&worklist, stmt, relevant_p, live_p);
|
|
}
|
|
}
|
|
|
|
|
|
/* 2. Process_worklist */
|
|
|
|
while (VEC_length (tree, worklist) > 0)
|
|
{
|
|
stmt = VEC_pop (tree, worklist);
|
|
|
|
if (vect_print_dump_info (REPORT_DETAILS))
|
|
{
|
|
fprintf (vect_dump, "worklist: examine stmt: ");
|
|
print_generic_expr (vect_dump, stmt, TDF_SLIM);
|
|
}
|
|
|
|
/* Examine the USEs of STMT. For each ssa-name USE thta is defined
|
|
in the loop, mark the stmt that defines it (DEF_STMT) as
|
|
relevant/irrelevant and live/dead according to the liveness and
|
|
relevance properties of STMT.
|
|
*/
|
|
|
|
gcc_assert (TREE_CODE (stmt) != PHI_NODE);
|
|
|
|
ann = stmt_ann (stmt);
|
|
stmt_vinfo = vinfo_for_stmt (stmt);
|
|
|
|
relevant_p = STMT_VINFO_RELEVANT_P (stmt_vinfo);
|
|
live_p = STMT_VINFO_LIVE_P (stmt_vinfo);
|
|
|
|
/* Generally, the liveness and relevance properties of STMT are
|
|
propagated to the DEF_STMTs of its USEs:
|
|
STMT_VINFO_LIVE_P (DEF_STMT_info) <-- live_p
|
|
STMT_VINFO_RELEVANT_P (DEF_STMT_info) <-- relevant_p
|
|
|
|
Exceptions:
|
|
|
|
(case 1)
|
|
If USE is used only for address computations (e.g. array indexing),
|
|
which does not need to be directly vectorized, then the
|
|
liveness/relevance of the respective DEF_STMT is left unchanged.
|
|
|
|
(case 2)
|
|
If STMT has been identified as defining a reduction variable, then
|
|
we have two cases:
|
|
(case 2.1)
|
|
The last use of STMT is the reduction-variable, which is defined
|
|
by a loop-header-phi. We don't want to mark the phi as live or
|
|
relevant (because it does not need to be vectorized, it is handled
|
|
as part of the vectorization of the reduction), so in this case we
|
|
skip the call to vect_mark_relevant.
|
|
(case 2.2)
|
|
The rest of the uses of STMT are defined in the loop body. For
|
|
the def_stmt of these uses we want to set liveness/relevance
|
|
as follows:
|
|
STMT_VINFO_LIVE_P (DEF_STMT_info) <-- false
|
|
STMT_VINFO_RELEVANT_P (DEF_STMT_info) <-- true
|
|
because even though STMT is classified as live (since it defines a
|
|
value that is used across loop iterations) and irrelevant (since it
|
|
is not used inside the loop), it will be vectorized, and therefore
|
|
the corresponding DEF_STMTs need to marked as relevant.
|
|
*/
|
|
|
|
/* case 2.2: */
|
|
if (STMT_VINFO_DEF_TYPE (stmt_vinfo) == vect_reduction_def)
|
|
{
|
|
gcc_assert (!relevant_p && live_p);
|
|
relevant_p = true;
|
|
live_p = false;
|
|
}
|
|
|
|
FOR_EACH_SSA_TREE_OPERAND (use, stmt, iter, SSA_OP_USE)
|
|
{
|
|
/* case 1: we are only interested in uses that need to be vectorized.
|
|
Uses that are used for address computation are not considered
|
|
relevant.
|
|
*/
|
|
if (!exist_non_indexing_operands_for_use_p (use, stmt))
|
|
continue;
|
|
|
|
if (!vect_is_simple_use (use, loop_vinfo, &def_stmt, &def, &dt))
|
|
{
|
|
if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS))
|
|
fprintf (vect_dump, "not vectorized: unsupported use in stmt.");
|
|
VEC_free (tree, heap, worklist);
|
|
return false;
|
|
}
|
|
|
|
if (!def_stmt || IS_EMPTY_STMT (def_stmt))
|
|
continue;
|
|
|
|
if (vect_print_dump_info (REPORT_DETAILS))
|
|
{
|
|
fprintf (vect_dump, "worklist: examine use %d: ", i);
|
|
print_generic_expr (vect_dump, use, TDF_SLIM);
|
|
}
|
|
|
|
bb = bb_for_stmt (def_stmt);
|
|
if (!flow_bb_inside_loop_p (loop, bb))
|
|
continue;
|
|
|
|
/* case 2.1: the reduction-use does not mark the defining-phi
|
|
as relevant. */
|
|
if (STMT_VINFO_DEF_TYPE (stmt_vinfo) == vect_reduction_def
|
|
&& TREE_CODE (def_stmt) == PHI_NODE)
|
|
continue;
|
|
|
|
vect_mark_relevant (&worklist, def_stmt, relevant_p, live_p);
|
|
}
|
|
} /* while worklist */
|
|
|
|
VEC_free (tree, heap, worklist);
|
|
return true;
|
|
}
|
|
|
|
|
|
/* Function vect_can_advance_ivs_p
|
|
|
|
In case the number of iterations that LOOP iterates is unknown at compile
|
|
time, an epilog loop will be generated, and the loop induction variables
|
|
(IVs) will be "advanced" to the value they are supposed to take just before
|
|
the epilog loop. Here we check that the access function of the loop IVs
|
|
and the expression that represents the loop bound are simple enough.
|
|
These restrictions will be relaxed in the future. */
|
|
|
|
static bool
|
|
vect_can_advance_ivs_p (loop_vec_info loop_vinfo)
|
|
{
|
|
struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo);
|
|
basic_block bb = loop->header;
|
|
tree phi;
|
|
|
|
/* Analyze phi functions of the loop header. */
|
|
|
|
if (vect_print_dump_info (REPORT_DETAILS))
|
|
fprintf (vect_dump, "=== vect_can_advance_ivs_p ===");
|
|
|
|
for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
|
|
{
|
|
tree access_fn = NULL;
|
|
tree evolution_part;
|
|
|
|
if (vect_print_dump_info (REPORT_DETAILS))
|
|
{
|
|
fprintf (vect_dump, "Analyze phi: ");
|
|
print_generic_expr (vect_dump, phi, TDF_SLIM);
|
|
}
|
|
|
|
/* Skip virtual phi's. The data dependences that are associated with
|
|
virtual defs/uses (i.e., memory accesses) are analyzed elsewhere. */
|
|
|
|
if (!is_gimple_reg (SSA_NAME_VAR (PHI_RESULT (phi))))
|
|
{
|
|
if (vect_print_dump_info (REPORT_DETAILS))
|
|
fprintf (vect_dump, "virtual phi. skip.");
|
|
continue;
|
|
}
|
|
|
|
/* Skip reduction phis. */
|
|
|
|
if (STMT_VINFO_DEF_TYPE (vinfo_for_stmt (phi)) == vect_reduction_def)
|
|
{
|
|
if (vect_print_dump_info (REPORT_DETAILS))
|
|
fprintf (vect_dump, "reduc phi. skip.");
|
|
continue;
|
|
}
|
|
|
|
/* Analyze the evolution function. */
|
|
|
|
access_fn = instantiate_parameters
|
|
(loop, analyze_scalar_evolution (loop, PHI_RESULT (phi)));
|
|
|
|
if (!access_fn)
|
|
{
|
|
if (vect_print_dump_info (REPORT_DETAILS))
|
|
fprintf (vect_dump, "No Access function.");
|
|
return false;
|
|
}
|
|
|
|
if (vect_print_dump_info (REPORT_DETAILS))
|
|
{
|
|
fprintf (vect_dump, "Access function of PHI: ");
|
|
print_generic_expr (vect_dump, access_fn, TDF_SLIM);
|
|
}
|
|
|
|
evolution_part = evolution_part_in_loop_num (access_fn, loop->num);
|
|
|
|
if (evolution_part == NULL_TREE)
|
|
{
|
|
if (vect_print_dump_info (REPORT_DETAILS))
|
|
fprintf (vect_dump, "No evolution.");
|
|
return false;
|
|
}
|
|
|
|
/* FORNOW: We do not transform initial conditions of IVs
|
|
which evolution functions are a polynomial of degree >= 2. */
|
|
|
|
if (tree_is_chrec (evolution_part))
|
|
return false;
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
|
|
/* Function vect_get_loop_niters.
|
|
|
|
Determine how many iterations the loop is executed.
|
|
If an expression that represents the number of iterations
|
|
can be constructed, place it in NUMBER_OF_ITERATIONS.
|
|
Return the loop exit condition. */
|
|
|
|
static tree
|
|
vect_get_loop_niters (struct loop *loop, tree *number_of_iterations)
|
|
{
|
|
tree niters;
|
|
|
|
if (vect_print_dump_info (REPORT_DETAILS))
|
|
fprintf (vect_dump, "=== get_loop_niters ===");
|
|
|
|
niters = number_of_iterations_in_loop (loop);
|
|
|
|
if (niters != NULL_TREE
|
|
&& niters != chrec_dont_know)
|
|
{
|
|
*number_of_iterations = niters;
|
|
|
|
if (vect_print_dump_info (REPORT_DETAILS))
|
|
{
|
|
fprintf (vect_dump, "==> get_loop_niters:" );
|
|
print_generic_expr (vect_dump, *number_of_iterations, TDF_SLIM);
|
|
}
|
|
}
|
|
|
|
return get_loop_exit_condition (loop);
|
|
}
|
|
|
|
|
|
/* Function vect_analyze_loop_form.
|
|
|
|
Verify the following restrictions (some may be relaxed in the future):
|
|
- it's an inner-most loop
|
|
- number of BBs = 2 (which are the loop header and the latch)
|
|
- the loop has a pre-header
|
|
- the loop has a single entry and exit
|
|
- the loop exit condition is simple enough, and the number of iterations
|
|
can be analyzed (a countable loop). */
|
|
|
|
static loop_vec_info
|
|
vect_analyze_loop_form (struct loop *loop)
|
|
{
|
|
loop_vec_info loop_vinfo;
|
|
tree loop_cond;
|
|
tree number_of_iterations = NULL;
|
|
|
|
if (vect_print_dump_info (REPORT_DETAILS))
|
|
fprintf (vect_dump, "=== vect_analyze_loop_form ===");
|
|
|
|
if (loop->inner)
|
|
{
|
|
if (vect_print_dump_info (REPORT_OUTER_LOOPS))
|
|
fprintf (vect_dump, "not vectorized: nested loop.");
|
|
return NULL;
|
|
}
|
|
|
|
if (!loop->single_exit
|
|
|| loop->num_nodes != 2
|
|
|| EDGE_COUNT (loop->header->preds) != 2)
|
|
{
|
|
if (vect_print_dump_info (REPORT_BAD_FORM_LOOPS))
|
|
{
|
|
if (!loop->single_exit)
|
|
fprintf (vect_dump, "not vectorized: multiple exits.");
|
|
else if (loop->num_nodes != 2)
|
|
fprintf (vect_dump, "not vectorized: too many BBs in loop.");
|
|
else if (EDGE_COUNT (loop->header->preds) != 2)
|
|
fprintf (vect_dump, "not vectorized: too many incoming edges.");
|
|
}
|
|
|
|
return NULL;
|
|
}
|
|
|
|
/* We assume that the loop exit condition is at the end of the loop. i.e,
|
|
that the loop is represented as a do-while (with a proper if-guard
|
|
before the loop if needed), where the loop header contains all the
|
|
executable statements, and the latch is empty. */
|
|
if (!empty_block_p (loop->latch))
|
|
{
|
|
if (vect_print_dump_info (REPORT_BAD_FORM_LOOPS))
|
|
fprintf (vect_dump, "not vectorized: unexpected loop form.");
|
|
return NULL;
|
|
}
|
|
|
|
/* Make sure there exists a single-predecessor exit bb: */
|
|
if (!single_pred_p (loop->single_exit->dest))
|
|
{
|
|
edge e = loop->single_exit;
|
|
if (!(e->flags & EDGE_ABNORMAL))
|
|
{
|
|
split_loop_exit_edge (e);
|
|
if (vect_print_dump_info (REPORT_DETAILS))
|
|
fprintf (vect_dump, "split exit edge.");
|
|
}
|
|
else
|
|
{
|
|
if (vect_print_dump_info (REPORT_BAD_FORM_LOOPS))
|
|
fprintf (vect_dump, "not vectorized: abnormal loop exit edge.");
|
|
return NULL;
|
|
}
|
|
}
|
|
|
|
if (empty_block_p (loop->header))
|
|
{
|
|
if (vect_print_dump_info (REPORT_BAD_FORM_LOOPS))
|
|
fprintf (vect_dump, "not vectorized: empty loop.");
|
|
return NULL;
|
|
}
|
|
|
|
loop_cond = vect_get_loop_niters (loop, &number_of_iterations);
|
|
if (!loop_cond)
|
|
{
|
|
if (vect_print_dump_info (REPORT_BAD_FORM_LOOPS))
|
|
fprintf (vect_dump, "not vectorized: complicated exit condition.");
|
|
return NULL;
|
|
}
|
|
|
|
if (!number_of_iterations)
|
|
{
|
|
if (vect_print_dump_info (REPORT_BAD_FORM_LOOPS))
|
|
fprintf (vect_dump,
|
|
"not vectorized: number of iterations cannot be computed.");
|
|
return NULL;
|
|
}
|
|
|
|
if (chrec_contains_undetermined (number_of_iterations))
|
|
{
|
|
if (vect_print_dump_info (REPORT_BAD_FORM_LOOPS))
|
|
fprintf (vect_dump, "Infinite number of iterations.");
|
|
return false;
|
|
}
|
|
|
|
loop_vinfo = new_loop_vec_info (loop);
|
|
LOOP_VINFO_NITERS (loop_vinfo) = number_of_iterations;
|
|
|
|
if (!LOOP_VINFO_NITERS_KNOWN_P (loop_vinfo))
|
|
{
|
|
if (vect_print_dump_info (REPORT_DETAILS))
|
|
{
|
|
fprintf (vect_dump, "Symbolic number of iterations is ");
|
|
print_generic_expr (vect_dump, number_of_iterations, TDF_DETAILS);
|
|
}
|
|
}
|
|
else
|
|
if (LOOP_VINFO_INT_NITERS (loop_vinfo) == 0)
|
|
{
|
|
if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS))
|
|
fprintf (vect_dump, "not vectorized: number of iterations = 0.");
|
|
return NULL;
|
|
}
|
|
|
|
LOOP_VINFO_EXIT_COND (loop_vinfo) = loop_cond;
|
|
|
|
return loop_vinfo;
|
|
}
|
|
|
|
|
|
/* Function vect_analyze_loop.
|
|
|
|
Apply a set of analyses on LOOP, and create a loop_vec_info struct
|
|
for it. The different analyses will record information in the
|
|
loop_vec_info struct. */
|
|
loop_vec_info
|
|
vect_analyze_loop (struct loop *loop)
|
|
{
|
|
bool ok;
|
|
loop_vec_info loop_vinfo;
|
|
|
|
if (vect_print_dump_info (REPORT_DETAILS))
|
|
fprintf (vect_dump, "===== analyze_loop_nest =====");
|
|
|
|
/* Check the CFG characteristics of the loop (nesting, entry/exit, etc. */
|
|
|
|
loop_vinfo = vect_analyze_loop_form (loop);
|
|
if (!loop_vinfo)
|
|
{
|
|
if (vect_print_dump_info (REPORT_DETAILS))
|
|
fprintf (vect_dump, "bad loop form.");
|
|
return NULL;
|
|
}
|
|
|
|
/* Find all data references in the loop (which correspond to vdefs/vuses)
|
|
and analyze their evolution in the loop.
|
|
|
|
FORNOW: Handle only simple, array references, which
|
|
alignment can be forced, and aligned pointer-references. */
|
|
|
|
ok = vect_analyze_data_refs (loop_vinfo);
|
|
if (!ok)
|
|
{
|
|
if (vect_print_dump_info (REPORT_DETAILS))
|
|
fprintf (vect_dump, "bad data references.");
|
|
destroy_loop_vec_info (loop_vinfo);
|
|
return NULL;
|
|
}
|
|
|
|
/* Classify all cross-iteration scalar data-flow cycles.
|
|
Cross-iteration cycles caused by virtual phis are analyzed separately. */
|
|
|
|
vect_analyze_scalar_cycles (loop_vinfo);
|
|
|
|
/* Data-flow analysis to detect stmts that do not need to be vectorized. */
|
|
|
|
ok = vect_mark_stmts_to_be_vectorized (loop_vinfo);
|
|
if (!ok)
|
|
{
|
|
if (vect_print_dump_info (REPORT_DETAILS))
|
|
fprintf (vect_dump, "unexpected pattern.");
|
|
destroy_loop_vec_info (loop_vinfo);
|
|
return NULL;
|
|
}
|
|
|
|
/* Analyze the alignment of the data-refs in the loop.
|
|
Fail if a data reference is found that cannot be vectorized. */
|
|
|
|
ok = vect_analyze_data_refs_alignment (loop_vinfo);
|
|
if (!ok)
|
|
{
|
|
if (vect_print_dump_info (REPORT_DETAILS))
|
|
fprintf (vect_dump, "bad data alignment.");
|
|
destroy_loop_vec_info (loop_vinfo);
|
|
return NULL;
|
|
}
|
|
|
|
ok = vect_determine_vectorization_factor (loop_vinfo);
|
|
if (!ok)
|
|
{
|
|
if (vect_print_dump_info (REPORT_DETAILS))
|
|
fprintf (vect_dump, "can't determine vectorization factor.");
|
|
destroy_loop_vec_info (loop_vinfo);
|
|
return NULL;
|
|
}
|
|
|
|
/* Analyze data dependences between the data-refs in the loop.
|
|
FORNOW: fail at the first data dependence that we encounter. */
|
|
|
|
ok = vect_analyze_data_ref_dependences (loop_vinfo);
|
|
if (!ok)
|
|
{
|
|
if (vect_print_dump_info (REPORT_DETAILS))
|
|
fprintf (vect_dump, "bad data dependence.");
|
|
destroy_loop_vec_info (loop_vinfo);
|
|
return NULL;
|
|
}
|
|
|
|
/* Analyze the access patterns of the data-refs in the loop (consecutive,
|
|
complex, etc.). FORNOW: Only handle consecutive access pattern. */
|
|
|
|
ok = vect_analyze_data_ref_accesses (loop_vinfo);
|
|
if (!ok)
|
|
{
|
|
if (vect_print_dump_info (REPORT_DETAILS))
|
|
fprintf (vect_dump, "bad data access.");
|
|
destroy_loop_vec_info (loop_vinfo);
|
|
return NULL;
|
|
}
|
|
|
|
/* This pass will decide on using loop versioning and/or loop peeling in
|
|
order to enhance the alignment of data references in the loop. */
|
|
|
|
ok = vect_enhance_data_refs_alignment (loop_vinfo);
|
|
if (!ok)
|
|
{
|
|
if (vect_print_dump_info (REPORT_DETAILS))
|
|
fprintf (vect_dump, "bad data alignment.");
|
|
destroy_loop_vec_info (loop_vinfo);
|
|
return NULL;
|
|
}
|
|
|
|
/* Scan all the operations in the loop and make sure they are
|
|
vectorizable. */
|
|
|
|
ok = vect_analyze_operations (loop_vinfo);
|
|
if (!ok)
|
|
{
|
|
if (vect_print_dump_info (REPORT_DETAILS))
|
|
fprintf (vect_dump, "bad operation or unsupported loop bound.");
|
|
destroy_loop_vec_info (loop_vinfo);
|
|
return NULL;
|
|
}
|
|
|
|
LOOP_VINFO_VECTORIZABLE_P (loop_vinfo) = 1;
|
|
|
|
return loop_vinfo;
|
|
}
|