640 lines
20 KiB
C
640 lines
20 KiB
C
/* Analysis Utilities for Loop Vectorization.
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Copyright (C) 2006 Free Software Foundation, Inc.
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Contributed by Dorit Nuzman <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 "target.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-data-ref.h"
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#include "tree-vectorizer.h"
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#include "recog.h"
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#include "toplev.h"
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/* Function prototypes */
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static void vect_pattern_recog_1
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(tree (* ) (tree, tree *, tree *), block_stmt_iterator);
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static bool widened_name_p (tree, tree, tree *, tree *);
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/* Pattern recognition functions */
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static tree vect_recog_widen_sum_pattern (tree, tree *, tree *);
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static tree vect_recog_widen_mult_pattern (tree, tree *, tree *);
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static tree vect_recog_dot_prod_pattern (tree, tree *, tree *);
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static vect_recog_func_ptr vect_vect_recog_func_ptrs[NUM_PATTERNS] = {
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vect_recog_widen_mult_pattern,
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vect_recog_widen_sum_pattern,
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vect_recog_dot_prod_pattern};
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/* Function widened_name_p
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Check whether NAME, an ssa-name used in USE_STMT,
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is a result of a type-promotion, such that:
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DEF_STMT: NAME = NOP (name0)
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where the type of name0 (HALF_TYPE) is smaller than the type of NAME.
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*/
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static bool
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widened_name_p (tree name, tree use_stmt, tree *half_type, tree *def_stmt)
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{
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tree dummy;
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loop_vec_info loop_vinfo;
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stmt_vec_info stmt_vinfo;
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tree expr;
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tree type = TREE_TYPE (name);
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tree oprnd0;
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enum vect_def_type dt;
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tree def;
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stmt_vinfo = vinfo_for_stmt (use_stmt);
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loop_vinfo = STMT_VINFO_LOOP_VINFO (stmt_vinfo);
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if (!vect_is_simple_use (name, loop_vinfo, def_stmt, &def, &dt))
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return false;
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if (dt != vect_loop_def
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&& dt != vect_invariant_def && dt != vect_constant_def)
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return false;
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if (! *def_stmt)
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return false;
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if (TREE_CODE (*def_stmt) != MODIFY_EXPR)
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return false;
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expr = TREE_OPERAND (*def_stmt, 1);
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if (TREE_CODE (expr) != NOP_EXPR)
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return false;
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oprnd0 = TREE_OPERAND (expr, 0);
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*half_type = TREE_TYPE (oprnd0);
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if (!INTEGRAL_TYPE_P (type) || !INTEGRAL_TYPE_P (*half_type)
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|| (TYPE_UNSIGNED (type) != TYPE_UNSIGNED (*half_type))
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|| (TYPE_PRECISION (type) < (TYPE_PRECISION (*half_type) * 2)))
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return false;
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if (!vect_is_simple_use (oprnd0, loop_vinfo, &dummy, &dummy, &dt))
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return false;
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if (dt != vect_invariant_def && dt != vect_constant_def
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&& dt != vect_loop_def)
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return false;
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return true;
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}
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/* Function vect_recog_dot_prod_pattern
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Try to find the following pattern:
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type x_t, y_t;
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TYPE1 prod;
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TYPE2 sum = init;
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loop:
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sum_0 = phi <init, sum_1>
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S1 x_t = ...
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S2 y_t = ...
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S3 x_T = (TYPE1) x_t;
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S4 y_T = (TYPE1) y_t;
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S5 prod = x_T * y_T;
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[S6 prod = (TYPE2) prod; #optional]
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S7 sum_1 = prod + sum_0;
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where 'TYPE1' is exactly double the size of type 'type', and 'TYPE2' is the
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same size of 'TYPE1' or bigger. This is a special case of a reduction
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computation.
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Input:
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* LAST_STMT: A stmt from which the pattern search begins. In the example,
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when this function is called with S7, the pattern {S3,S4,S5,S6,S7} will be
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detected.
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Output:
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* TYPE_IN: The type of the input arguments to the pattern.
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* TYPE_OUT: The type of the output of this pattern.
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* Return value: A new stmt that will be used to replace the sequence of
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stmts that constitute the pattern. In this case it will be:
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WIDEN_DOT_PRODUCT <x_t, y_t, sum_0>
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*/
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static tree
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vect_recog_dot_prod_pattern (tree last_stmt, tree *type_in, tree *type_out)
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{
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tree stmt, expr;
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tree oprnd0, oprnd1;
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tree oprnd00, oprnd01;
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stmt_vec_info stmt_vinfo = vinfo_for_stmt (last_stmt);
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tree type, half_type;
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tree pattern_expr;
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tree prod_type;
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if (TREE_CODE (last_stmt) != MODIFY_EXPR)
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return NULL;
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expr = TREE_OPERAND (last_stmt, 1);
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type = TREE_TYPE (expr);
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/* Look for the following pattern
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DX = (TYPE1) X;
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DY = (TYPE1) Y;
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DPROD = DX * DY;
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DDPROD = (TYPE2) DPROD;
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sum_1 = DDPROD + sum_0;
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In which
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- DX is double the size of X
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- DY is double the size of Y
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- DX, DY, DPROD all have the same type
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- sum is the same size of DPROD or bigger
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- sum has been recognized as a reduction variable.
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This is equivalent to:
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DPROD = X w* Y; #widen mult
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sum_1 = DPROD w+ sum_0; #widen summation
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or
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DPROD = X w* Y; #widen mult
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sum_1 = DPROD + sum_0; #summation
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*/
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/* Starting from LAST_STMT, follow the defs of its uses in search
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of the above pattern. */
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if (TREE_CODE (expr) != PLUS_EXPR)
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return NULL;
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if (STMT_VINFO_IN_PATTERN_P (stmt_vinfo))
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{
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/* Has been detected as widening-summation? */
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stmt = STMT_VINFO_RELATED_STMT (stmt_vinfo);
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expr = TREE_OPERAND (stmt, 1);
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type = TREE_TYPE (expr);
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if (TREE_CODE (expr) != WIDEN_SUM_EXPR)
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return NULL;
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oprnd0 = TREE_OPERAND (expr, 0);
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oprnd1 = TREE_OPERAND (expr, 1);
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half_type = TREE_TYPE (oprnd0);
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}
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else
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{
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tree def_stmt;
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if (STMT_VINFO_DEF_TYPE (stmt_vinfo) != vect_reduction_def)
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return NULL;
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oprnd0 = TREE_OPERAND (expr, 0);
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oprnd1 = TREE_OPERAND (expr, 1);
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if (TYPE_MAIN_VARIANT (TREE_TYPE (oprnd0)) != TYPE_MAIN_VARIANT (type)
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|| TYPE_MAIN_VARIANT (TREE_TYPE (oprnd1)) != TYPE_MAIN_VARIANT (type))
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return NULL;
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stmt = last_stmt;
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if (widened_name_p (oprnd0, stmt, &half_type, &def_stmt))
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{
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stmt = def_stmt;
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expr = TREE_OPERAND (stmt, 1);
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oprnd0 = TREE_OPERAND (expr, 0);
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}
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else
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half_type = type;
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}
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/* So far so good. Since last_stmt was detected as a (summation) reduction,
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we know that oprnd1 is the reduction variable (defined by a loop-header
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phi), and oprnd0 is an ssa-name defined by a stmt in the loop body.
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Left to check that oprnd0 is defined by a (widen_)mult_expr */
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prod_type = half_type;
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stmt = SSA_NAME_DEF_STMT (oprnd0);
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gcc_assert (stmt);
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stmt_vinfo = vinfo_for_stmt (stmt);
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gcc_assert (stmt_vinfo);
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if (STMT_VINFO_DEF_TYPE (stmt_vinfo) != vect_loop_def)
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return NULL;
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expr = TREE_OPERAND (stmt, 1);
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if (TREE_CODE (expr) != MULT_EXPR)
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return NULL;
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if (STMT_VINFO_IN_PATTERN_P (stmt_vinfo))
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{
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/* Has been detected as a widening multiplication? */
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stmt = STMT_VINFO_RELATED_STMT (stmt_vinfo);
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expr = TREE_OPERAND (stmt, 1);
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if (TREE_CODE (expr) != WIDEN_MULT_EXPR)
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return NULL;
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stmt_vinfo = vinfo_for_stmt (stmt);
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gcc_assert (stmt_vinfo);
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gcc_assert (STMT_VINFO_DEF_TYPE (stmt_vinfo) == vect_loop_def);
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oprnd00 = TREE_OPERAND (expr, 0);
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oprnd01 = TREE_OPERAND (expr, 1);
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}
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else
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{
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tree half_type0, half_type1;
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tree def_stmt;
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tree oprnd0, oprnd1;
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oprnd0 = TREE_OPERAND (expr, 0);
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oprnd1 = TREE_OPERAND (expr, 1);
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if (TYPE_MAIN_VARIANT (TREE_TYPE (oprnd0))
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!= TYPE_MAIN_VARIANT (prod_type)
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|| TYPE_MAIN_VARIANT (TREE_TYPE (oprnd1))
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!= TYPE_MAIN_VARIANT (prod_type))
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return NULL;
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if (!widened_name_p (oprnd0, stmt, &half_type0, &def_stmt))
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return NULL;
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oprnd00 = TREE_OPERAND (TREE_OPERAND (def_stmt, 1), 0);
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if (!widened_name_p (oprnd1, stmt, &half_type1, &def_stmt))
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return NULL;
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oprnd01 = TREE_OPERAND (TREE_OPERAND (def_stmt, 1), 0);
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if (TYPE_MAIN_VARIANT (half_type0) != TYPE_MAIN_VARIANT (half_type1))
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return NULL;
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if (TYPE_PRECISION (prod_type) != TYPE_PRECISION (half_type0) * 2)
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return NULL;
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}
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half_type = TREE_TYPE (oprnd00);
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*type_in = half_type;
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*type_out = type;
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/* Pattern detected. Create a stmt to be used to replace the pattern: */
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pattern_expr = build3 (DOT_PROD_EXPR, type, oprnd00, oprnd01, oprnd1);
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if (vect_print_dump_info (REPORT_DETAILS))
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{
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fprintf (vect_dump, "vect_recog_dot_prod_pattern: detected: ");
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print_generic_expr (vect_dump, pattern_expr, TDF_SLIM);
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}
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return pattern_expr;
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}
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/* Function vect_recog_widen_mult_pattern
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Try to find the following pattern:
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type a_t, b_t;
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TYPE a_T, b_T, prod_T;
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S1 a_t = ;
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S2 b_t = ;
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S3 a_T = (TYPE) a_t;
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S4 b_T = (TYPE) b_t;
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S5 prod_T = a_T * b_T;
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where type 'TYPE' is at least double the size of type 'type'.
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Input:
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* LAST_STMT: A stmt from which the pattern search begins. In the example,
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when this function is called with S5, the pattern {S3,S4,S5} is be detected.
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Output:
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* TYPE_IN: The type of the input arguments to the pattern.
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* TYPE_OUT: The type of the output of this pattern.
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* Return value: A new stmt that will be used to replace the sequence of
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stmts that constitute the pattern. In this case it will be:
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WIDEN_MULT <a_t, b_t>
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*/
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static tree
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vect_recog_widen_mult_pattern (tree last_stmt ATTRIBUTE_UNUSED,
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tree *type_in ATTRIBUTE_UNUSED,
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tree *type_out ATTRIBUTE_UNUSED)
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{
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/* Yet to be implemented. */
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return NULL;
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}
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/* Function vect_recog_widen_sum_pattern
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Try to find the following pattern:
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type x_t;
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TYPE x_T, sum = init;
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loop:
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sum_0 = phi <init, sum_1>
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S1 x_t = *p;
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S2 x_T = (TYPE) x_t;
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S3 sum_1 = x_T + sum_0;
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where type 'TYPE' is at least double the size of type 'type', i.e - we're
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summing elements of type 'type' into an accumulator of type 'TYPE'. This is
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a special case of a reduction computation.
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Input:
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* LAST_STMT: A stmt from which the pattern search begins. In the example,
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when this function is called with S3, the pattern {S2,S3} will be detected.
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Output:
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* TYPE_IN: The type of the input arguments to the pattern.
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* TYPE_OUT: The type of the output of this pattern.
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* Return value: A new stmt that will be used to replace the sequence of
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stmts that constitute the pattern. In this case it will be:
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WIDEN_SUM <x_t, sum_0>
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*/
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static tree
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vect_recog_widen_sum_pattern (tree last_stmt, tree *type_in, tree *type_out)
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{
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tree stmt, expr;
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tree oprnd0, oprnd1;
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stmt_vec_info stmt_vinfo = vinfo_for_stmt (last_stmt);
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tree type, half_type;
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tree pattern_expr;
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if (TREE_CODE (last_stmt) != MODIFY_EXPR)
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return NULL;
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expr = TREE_OPERAND (last_stmt, 1);
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type = TREE_TYPE (expr);
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/* Look for the following pattern
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DX = (TYPE) X;
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sum_1 = DX + sum_0;
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In which DX is at least double the size of X, and sum_1 has been
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recognized as a reduction variable.
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*/
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/* Starting from LAST_STMT, follow the defs of its uses in search
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of the above pattern. */
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if (TREE_CODE (expr) != PLUS_EXPR)
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return NULL;
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if (STMT_VINFO_DEF_TYPE (stmt_vinfo) != vect_reduction_def)
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return NULL;
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oprnd0 = TREE_OPERAND (expr, 0);
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oprnd1 = TREE_OPERAND (expr, 1);
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if (TYPE_MAIN_VARIANT (TREE_TYPE (oprnd0)) != TYPE_MAIN_VARIANT (type)
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|| TYPE_MAIN_VARIANT (TREE_TYPE (oprnd1)) != TYPE_MAIN_VARIANT (type))
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return NULL;
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/* So far so good. Since last_stmt was detected as a (summation) reduction,
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we know that oprnd1 is the reduction variable (defined by a loop-header
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phi), and oprnd0 is an ssa-name defined by a stmt in the loop body.
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Left to check that oprnd0 is defined by a cast from type 'type' to type
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'TYPE'. */
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if (!widened_name_p (oprnd0, last_stmt, &half_type, &stmt))
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return NULL;
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oprnd0 = TREE_OPERAND (TREE_OPERAND (stmt, 1), 0);
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*type_in = half_type;
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*type_out = type;
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/* Pattern detected. Create a stmt to be used to replace the pattern: */
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pattern_expr = build2 (WIDEN_SUM_EXPR, type, oprnd0, oprnd1);
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if (vect_print_dump_info (REPORT_DETAILS))
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{
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fprintf (vect_dump, "vect_recog_widen_sum_pattern: detected: ");
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print_generic_expr (vect_dump, pattern_expr, TDF_SLIM);
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}
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return pattern_expr;
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}
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/* Function vect_pattern_recog_1
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Input:
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PATTERN_RECOG_FUNC: A pointer to a function that detects a certain
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computation pattern.
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STMT: A stmt from which the pattern search should start.
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If PATTERN_RECOG_FUNC successfully detected the pattern, it creates an
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expression that computes the same functionality and can be used to
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replace the sequence of stmts that are involved in the pattern.
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Output:
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This function checks if the expression returned by PATTERN_RECOG_FUNC is
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supported in vector form by the target. We use 'TYPE_IN' to obtain the
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relevant vector type. If 'TYPE_IN' is already a vector type, then this
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indicates that target support had already been checked by PATTERN_RECOG_FUNC.
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If 'TYPE_OUT' is also returned by PATTERN_RECOG_FUNC, we check that it fits
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to the available target pattern.
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This function also does some bookkeeping, as explained in the documentation
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for vect_recog_pattern. */
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static void
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vect_pattern_recog_1 (
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tree (* vect_recog_func) (tree, tree *, tree *),
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block_stmt_iterator 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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stmt_vec_info pattern_stmt_info;
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loop_vec_info loop_vinfo = STMT_VINFO_LOOP_VINFO (stmt_info);
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tree pattern_expr;
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tree pattern_vectype;
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tree type_in, type_out;
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tree pattern_type;
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enum tree_code code;
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tree var, var_name;
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stmt_ann_t ann;
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pattern_expr = (* vect_recog_func) (stmt, &type_in, &type_out);
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if (!pattern_expr)
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return;
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if (VECTOR_MODE_P (TYPE_MODE (type_in)))
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{
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/* No need to check target support (already checked by the pattern
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recognition function). */
|
|
pattern_vectype = type_in;
|
|
}
|
|
else
|
|
{
|
|
enum machine_mode vec_mode;
|
|
enum insn_code icode;
|
|
optab optab;
|
|
|
|
/* Check target support */
|
|
pattern_vectype = get_vectype_for_scalar_type (type_in);
|
|
optab = optab_for_tree_code (TREE_CODE (pattern_expr), pattern_vectype);
|
|
vec_mode = TYPE_MODE (pattern_vectype);
|
|
if (!optab
|
|
|| (icode = optab->handlers[(int) vec_mode].insn_code) ==
|
|
CODE_FOR_nothing
|
|
|| (type_out
|
|
&& (!get_vectype_for_scalar_type (type_out)
|
|
|| (insn_data[icode].operand[0].mode !=
|
|
TYPE_MODE (get_vectype_for_scalar_type (type_out))))))
|
|
return;
|
|
}
|
|
|
|
/* Found a vectorizable pattern. */
|
|
if (vect_print_dump_info (REPORT_DETAILS))
|
|
{
|
|
fprintf (vect_dump, "pattern recognized: ");
|
|
print_generic_expr (vect_dump, pattern_expr, TDF_SLIM);
|
|
}
|
|
|
|
/* Mark the stmts that are involved in the pattern,
|
|
create a new stmt to express the pattern and insert it. */
|
|
code = TREE_CODE (pattern_expr);
|
|
pattern_type = TREE_TYPE (pattern_expr);
|
|
var = create_tmp_var (pattern_type, "patt");
|
|
add_referenced_var (var);
|
|
var_name = make_ssa_name (var, NULL_TREE);
|
|
pattern_expr = build2 (MODIFY_EXPR, void_type_node, var_name, pattern_expr);
|
|
SSA_NAME_DEF_STMT (var_name) = pattern_expr;
|
|
bsi_insert_before (&si, pattern_expr, BSI_SAME_STMT);
|
|
ann = stmt_ann (pattern_expr);
|
|
set_stmt_info (ann, new_stmt_vec_info (pattern_expr, loop_vinfo));
|
|
pattern_stmt_info = vinfo_for_stmt (pattern_expr);
|
|
|
|
STMT_VINFO_RELATED_STMT (pattern_stmt_info) = stmt;
|
|
STMT_VINFO_DEF_TYPE (pattern_stmt_info) = STMT_VINFO_DEF_TYPE (stmt_info);
|
|
STMT_VINFO_VECTYPE (pattern_stmt_info) = pattern_vectype;
|
|
STMT_VINFO_IN_PATTERN_P (stmt_info) = true;
|
|
STMT_VINFO_RELATED_STMT (stmt_info) = pattern_expr;
|
|
|
|
return;
|
|
}
|
|
|
|
|
|
/* Function vect_pattern_recog
|
|
|
|
Input:
|
|
LOOP_VINFO - a struct_loop_info of a loop in which we want to look for
|
|
computation idioms.
|
|
|
|
Output - for each computation idiom that is detected we insert a new stmt
|
|
that provides the same functionality and that can be vectorized. We
|
|
also record some information in the struct_stmt_info of the relevant
|
|
stmts, as explained below:
|
|
|
|
At the entry to this function we have the following stmts, with the
|
|
following initial value in the STMT_VINFO fields:
|
|
|
|
stmt in_pattern_p related_stmt vec_stmt
|
|
S1: a_i = .... - - -
|
|
S2: a_2 = ..use(a_i).. - - -
|
|
S3: a_1 = ..use(a_2).. - - -
|
|
S4: a_0 = ..use(a_1).. - - -
|
|
S5: ... = ..use(a_0).. - - -
|
|
|
|
Say the sequence {S1,S2,S3,S4} was detected as a pattern that can be
|
|
represented by a single stmt. We then:
|
|
- create a new stmt S6 that will replace the pattern.
|
|
- insert the new stmt S6 before the last stmt in the pattern
|
|
- fill in the STMT_VINFO fields as follows:
|
|
|
|
in_pattern_p related_stmt vec_stmt
|
|
S1: a_i = .... - - -
|
|
S2: a_2 = ..use(a_i).. - - -
|
|
S3: a_1 = ..use(a_2).. - - -
|
|
> S6: a_new = .... - S4 -
|
|
S4: a_0 = ..use(a_1).. true S6 -
|
|
S5: ... = ..use(a_0).. - - -
|
|
|
|
(the last stmt in the pattern (S4) and the new pattern stmt (S6) point
|
|
to each other through the RELATED_STMT field).
|
|
|
|
S6 will be marked as relevant in vect_mark_stmts_to_be_vectorized instead
|
|
of S4 because it will replace all its uses. Stmts {S1,S2,S3} will
|
|
remain irrelevant unless used by stmts other than S4.
|
|
|
|
If vectorization succeeds, vect_transform_stmt will skip over {S1,S2,S3}
|
|
(because they are marked as irrelevant). It will vectorize S6, and record
|
|
a pointer to the new vector stmt VS6 both from S6 (as usual), and also
|
|
from S4. We do that so that when we get to vectorizing stmts that use the
|
|
def of S4 (like S5 that uses a_0), we'll know where to take the relevant
|
|
vector-def from. S4 will be skipped, and S5 will be vectorized as usual:
|
|
|
|
in_pattern_p related_stmt vec_stmt
|
|
S1: a_i = .... - - -
|
|
S2: a_2 = ..use(a_i).. - - -
|
|
S3: a_1 = ..use(a_2).. - - -
|
|
> VS6: va_new = .... - - -
|
|
S6: a_new = .... - S4 VS6
|
|
S4: a_0 = ..use(a_1).. true S6 VS6
|
|
> VS5: ... = ..vuse(va_new).. - - -
|
|
S5: ... = ..use(a_0).. - - -
|
|
|
|
DCE could then get rid of {S1,S2,S3,S4,S5,S6} (if their defs are not used
|
|
elsewhere), and we'll end up with:
|
|
|
|
VS6: va_new = ....
|
|
VS5: ... = ..vuse(va_new)..
|
|
|
|
If vectorization does not succeed, DCE will clean S6 away (its def is
|
|
not used), and we'll end up with the original sequence.
|
|
*/
|
|
|
|
void
|
|
vect_pattern_recog (loop_vec_info loop_vinfo)
|
|
{
|
|
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;
|
|
unsigned int i, j;
|
|
tree (* vect_recog_func_ptr) (tree, tree *, tree *);
|
|
|
|
if (vect_print_dump_info (REPORT_DETAILS))
|
|
fprintf (vect_dump, "=== vect_pattern_recog ===");
|
|
|
|
/* Scan through the loop stmts, applying the pattern recognition
|
|
functions starting at each stmt visited: */
|
|
for (i = 0; i < nbbs; i++)
|
|
{
|
|
basic_block bb = bbs[i];
|
|
for (si = bsi_start (bb); !bsi_end_p (si); bsi_next (&si))
|
|
{
|
|
stmt = bsi_stmt (si);
|
|
|
|
/* Scan over all generic vect_recog_xxx_pattern functions. */
|
|
for (j = 0; j < NUM_PATTERNS; j++)
|
|
{
|
|
vect_recog_func_ptr = vect_vect_recog_func_ptrs[j];
|
|
vect_pattern_recog_1 (vect_recog_func_ptr, si);
|
|
}
|
|
}
|
|
}
|
|
}
|