X-Git-Url: http://git.sourceforge.jp/view?p=pf3gnuchains%2Fgcc-fork.git;a=blobdiff_plain;f=gcc%2Ftree-if-conv.c;h=efbe509e7994f99589367e3d4d1b684f752b4799;hp=044c2b9598c1849e895445f44bb58f861b75ba5d;hb=de2bc49318bb75a38a6fa668fd5553cd8d92f19d;hpb=5e13091d5313c768a47371c450fabde2cc2dc3a7 diff --git a/gcc/tree-if-conv.c b/gcc/tree-if-conv.c index 044c2b9598c..efbe509e799 100644 --- a/gcc/tree-if-conv.c +++ b/gcc/tree-if-conv.c @@ -1,12 +1,13 @@ /* If-conversion for vectorizer. - Copyright (C) 2004, 2005, 2006, 2007 Free Software Foundation, Inc. + Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009 + Free Software Foundation, Inc. Contributed by Devang Patel This file is part of GCC. GCC is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free -Software Foundation; either version 2, or (at your option) any later +Software Foundation; either version 3, or (at your option) any later version. GCC is distributed in the hope that it will be useful, but WITHOUT ANY @@ -15,12 +16,12 @@ FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License -along with GCC; see the file COPYING. If not, write to the Free -Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA -02110-1301, USA. */ +along with GCC; see the file COPYING3. If not see +. */ -/* This pass implements tree level if-conversion transformation of loops. - Initial goal is to help vectorizer vectorize loops with conditions. +/* This pass implements a tree level if-conversion of loops. Its + initial goal is to help the vectorizer to vectorize loops with + conditions. A short description of if-conversion: @@ -85,10 +86,8 @@ Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA #include "coretypes.h" #include "tm.h" #include "tree.h" -#include "c-common.h" #include "flags.h" #include "timevar.h" -#include "varray.h" #include "rtl.h" #include "basic-block.h" #include "diagnostic.h" @@ -101,149 +100,197 @@ Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA #include "tree-pass.h" #include "target.h" -/* local function prototypes */ -static unsigned int main_tree_if_conversion (void); -static tree tree_if_convert_stmt (struct loop *loop, tree, tree, - block_stmt_iterator *); -static void tree_if_convert_cond_expr (struct loop *, tree, tree, - block_stmt_iterator *); -static bool if_convertible_phi_p (struct loop *, basic_block, tree); -static bool if_convertible_gimple_modify_stmt_p (struct loop *, basic_block, - tree); -static bool if_convertible_stmt_p (struct loop *, basic_block, tree); -static bool if_convertible_bb_p (struct loop *, basic_block, basic_block); -static bool if_convertible_loop_p (struct loop *, bool); -static void add_to_predicate_list (basic_block, tree); -static tree add_to_dst_predicate_list (struct loop * loop, edge, - tree, tree, - block_stmt_iterator *); -static void clean_predicate_lists (struct loop *loop); -static basic_block find_phi_replacement_condition (struct loop *loop, - basic_block, tree *, - block_stmt_iterator *); -static void replace_phi_with_cond_gimple_modify_stmt (tree, tree, basic_block, - block_stmt_iterator *); -static void process_phi_nodes (struct loop *); -static void combine_blocks (struct loop *); -static tree ifc_temp_var (tree, tree); -static bool pred_blocks_visited_p (basic_block, bitmap *); -static basic_block * get_loop_body_in_if_conv_order (const struct loop *loop); -static bool bb_with_exit_edge_p (struct loop *, basic_block); - /* List of basic blocks in if-conversion-suitable order. */ static basic_block *ifc_bbs; -/* Main entry point. - Apply if-conversion to the LOOP. Return true if successful otherwise return - false. If false is returned then loop remains unchanged. - FOR_VECTORIZER is a boolean flag. It indicates whether if-conversion is used - for vectorizer or not. If it is used for vectorizer, additional checks are - used. (Vectorization checks are not yet implemented). */ +/* Make a new temp variable of type TYPE. Add GIMPLE_ASSIGN to assign EXP + to the new variable. */ -static bool -tree_if_conversion (struct loop *loop, bool for_vectorizer) +static gimple +ifc_temp_var (tree type, tree exp) { - basic_block bb; - block_stmt_iterator itr; - unsigned int i; + const char *name = "_ifc_"; + tree var, new_name; + gimple stmt; - ifc_bbs = NULL; + /* Create new temporary variable. */ + var = create_tmp_var (type, name); + add_referenced_var (var); - /* if-conversion is not appropriate for all loops. First, check if loop is - if-convertible or not. */ - if (!if_convertible_loop_p (loop, for_vectorizer)) - { - if (dump_file && (dump_flags & TDF_DETAILS)) - fprintf (dump_file,"-------------------------\n"); - if (ifc_bbs) - { - free (ifc_bbs); - ifc_bbs = NULL; - } - free_dominance_info (CDI_POST_DOMINATORS); - return false; - } + /* Build new statement to assign EXP to new variable. */ + stmt = gimple_build_assign (var, exp); - /* Do actual work now. */ - for (i = 0; i < loop->num_nodes; i++) + /* Get SSA name for the new variable and set make new statement + its definition statement. */ + new_name = make_ssa_name (var, stmt); + gimple_assign_set_lhs (stmt, new_name); + SSA_NAME_DEF_STMT (new_name) = stmt; + update_stmt (stmt); + + return stmt; +} + +/* Add condition COND into predicate list of basic block BB. */ + +static void +add_to_predicate_list (basic_block bb, tree new_cond) +{ + tree cond = (tree) bb->aux; + + if (cond) + cond = fold_build2_loc (EXPR_LOCATION (cond), + TRUTH_OR_EXPR, boolean_type_node, + unshare_expr (cond), new_cond); + else + cond = new_cond; + + bb->aux = cond; +} + +/* Add condition COND into BB's predicate list. PREV_COND is + existing condition. */ + +static tree +add_to_dst_predicate_list (struct loop *loop, edge e, + tree prev_cond, tree cond, + gimple_stmt_iterator *gsi) +{ + tree new_cond = NULL_TREE; + + if (!flow_bb_inside_loop_p (loop, e->dest)) + return NULL_TREE; + + if (prev_cond == boolean_true_node || !prev_cond) + new_cond = unshare_expr (cond); + else { - tree cond; + tree tmp; + gimple tmp_stmt = NULL; - bb = ifc_bbs [i]; + prev_cond = force_gimple_operand_gsi (gsi, unshare_expr (prev_cond), + true, NULL, true, GSI_SAME_STMT); - /* Update condition using predicate list. */ - cond = bb->aux; + cond = force_gimple_operand_gsi (gsi, unshare_expr (cond), + true, NULL, true, GSI_SAME_STMT); - /* Process all statements in this basic block. - Remove conditional expression, if any, and annotate - destination basic block(s) appropriately. */ - for (itr = bsi_start (bb); !bsi_end_p (itr); /* empty */) - { - tree t = bsi_stmt (itr); - cond = tree_if_convert_stmt (loop, t, cond, &itr); - if (!bsi_end_p (itr)) - bsi_next (&itr); - } + /* Add the condition to aux field of the edge. In case edge + destination is a PHI node, this condition will be ANDed with + block predicate to construct complete condition. */ + e->aux = cond; - /* If current bb has only one successor, then consider it as an - unconditional goto. */ - if (single_succ_p (bb)) - { - basic_block bb_n = single_succ (bb); - if (cond != NULL_TREE) - add_to_predicate_list (bb_n, cond); - } + tmp = build2 (TRUTH_AND_EXPR, boolean_type_node, + unshare_expr (prev_cond), cond); + tmp_stmt = ifc_temp_var (boolean_type_node, tmp); + gsi_insert_before (gsi, tmp_stmt, GSI_SAME_STMT); + new_cond = gimple_assign_lhs (tmp_stmt); } - /* Now, all statements are if-converted and basic blocks are - annotated appropriately. Combine all basic block into one huge - basic block. */ - combine_blocks (loop); + add_to_predicate_list (e->dest, new_cond); + return new_cond; +} - /* clean up */ - clean_predicate_lists (loop); - free (ifc_bbs); - ifc_bbs = NULL; +/* Return true if one of the basic block BB edge is exit of LOOP. */ - return true; +static bool +bb_with_exit_edge_p (struct loop *loop, basic_block bb) +{ + edge e; + edge_iterator ei; + bool exit_edge_found = false; + + FOR_EACH_EDGE (e, ei, bb->succs) + if (loop_exit_edge_p (loop, e)) + { + exit_edge_found = true; + break; + } + + return exit_edge_found; } -/* if-convert stmt T which is part of LOOP. - If T is a GIMPLE_MODIFY_STMT than it is converted into conditional modify +/* STMT is a GIMPLE_COND. Update two destination's predicate list. + Remove COND_EXPR, if it is not the loop exit condition. Otherwise + update loop exit condition appropriately. GSI is the iterator + used to traverse statement list. STMT is part of loop LOOP. */ + +static void +tree_if_convert_cond_stmt (struct loop *loop, gimple stmt, tree cond, + gimple_stmt_iterator *gsi) +{ + tree c2; + edge true_edge, false_edge; + location_t loc = gimple_location (stmt); + tree c = fold_build2_loc (loc, gimple_cond_code (stmt), boolean_type_node, + gimple_cond_lhs (stmt), gimple_cond_rhs (stmt)); + + extract_true_false_edges_from_block (gimple_bb (stmt), + &true_edge, &false_edge); + + /* Add new condition into destination's predicate list. */ + + /* If C is true, then TRUE_EDGE is taken. */ + add_to_dst_predicate_list (loop, true_edge, cond, c, gsi); + + /* If C is false, then FALSE_EDGE is taken. */ + c2 = invert_truthvalue_loc (loc, unshare_expr (c)); + add_to_dst_predicate_list (loop, false_edge, cond, c2, gsi); + + /* Now this conditional statement is redundant. Remove it. + But, do not remove exit condition! Update exit condition + using new condition. */ + if (!bb_with_exit_edge_p (loop, gimple_bb (stmt))) + { + gsi_remove (gsi, true); + cond = NULL_TREE; + } + return; +} + +/* If-convert stmt T which is part of LOOP. + If T is a GIMPLE_ASSIGN then it is converted into conditional modify expression using COND. For conditional expressions, add condition in the destination basic block's predicate list and remove conditional - expression itself. BSI is the iterator used to traverse statements of - loop. It is used here when it is required to delete current statement. */ + expression itself. BSI is the iterator used to traverse statements of + loop. It is used here when it is required to delete current statement. */ static tree -tree_if_convert_stmt (struct loop * loop, tree t, tree cond, - block_stmt_iterator *bsi) +tree_if_convert_stmt (struct loop *loop, gimple t, tree cond, + gimple_stmt_iterator *gsi) { if (dump_file && (dump_flags & TDF_DETAILS)) { fprintf (dump_file, "------if-convert stmt\n"); - print_generic_stmt (dump_file, t, TDF_SLIM); + print_gimple_stmt (dump_file, t, 0, TDF_SLIM); print_generic_stmt (dump_file, cond, TDF_SLIM); } - switch (TREE_CODE (t)) + switch (gimple_code (t)) { /* Labels are harmless here. */ - case LABEL_EXPR: + case GIMPLE_LABEL: + break; + + case GIMPLE_DEBUG: + /* ??? Should there be conditional GIMPLE_DEBUG_BINDs? */ + if (gimple_debug_bind_p (gsi_stmt (*gsi))) + { + gimple_debug_bind_reset_value (gsi_stmt (*gsi)); + update_stmt (gsi_stmt (*gsi)); + } break; - case GIMPLE_MODIFY_STMT: - /* This GIMPLE_MODIFY_STMT is killing previous value of LHS. Appropriate - value will be selected by PHI node based on condition. It is possible + case GIMPLE_ASSIGN: + /* This GIMPLE_ASSIGN is killing previous value of LHS. Appropriate + value will be selected by PHI node based on condition. It is possible that before this transformation, PHI nodes was selecting default - value and now it will use this new value. This is OK because it does - not change validity the program. */ + value and now it will use this new value. This is OK because it does + not change the validity of the program. */ break; - case COND_EXPR: + case GIMPLE_COND: /* Update destination blocks' predicate list and remove this condition expression. */ - tree_if_convert_cond_expr (loop, t, cond, bsi); + tree_if_convert_cond_stmt (loop, t, cond, gsi); cond = NULL_TREE; break; @@ -253,75 +300,43 @@ tree_if_convert_stmt (struct loop * loop, tree t, tree cond, return cond; } -/* STMT is COND_EXPR. Update two destination's predicate list. - Remove COND_EXPR, if it is not the loop exit condition. Otherwise - update loop exit condition appropriately. BSI is the iterator - used to traverse statement list. STMT is part of loop LOOP. */ - -static void -tree_if_convert_cond_expr (struct loop *loop, tree stmt, tree cond, - block_stmt_iterator *bsi) -{ - tree c, c2; - edge true_edge, false_edge; - - gcc_assert (TREE_CODE (stmt) == COND_EXPR); - - c = COND_EXPR_COND (stmt); - - extract_true_false_edges_from_block (bb_for_stmt (stmt), - &true_edge, &false_edge); - - /* Add new condition into destination's predicate list. */ - - /* If 'c' is true then TRUE_EDGE is taken. */ - add_to_dst_predicate_list (loop, true_edge, cond, - unshare_expr (c), bsi); - - /* If 'c' is false then FALSE_EDGE is taken. */ - c2 = invert_truthvalue (unshare_expr (c)); - add_to_dst_predicate_list (loop, false_edge, cond, c2, bsi); - - /* Now this conditional statement is redundant. Remove it. - But, do not remove exit condition! Update exit condition - using new condition. */ - if (!bb_with_exit_edge_p (loop, bb_for_stmt (stmt))) - { - bsi_remove (bsi, true); - cond = NULL_TREE; - } - return; -} - -/* Return true, iff PHI is if-convertible. PHI is part of loop LOOP +/* Return true, iff PHI is if-convertible. PHI is part of loop LOOP and it belongs to basic block BB. PHI is not if-convertible - - if it has more than 2 arguments. - - Virtual PHI is immediately used in another PHI node. */ + - if it has more than 2 arguments, + - virtual PHI is immediately used in another PHI node, + - virtual PHI on BB other than header. */ static bool -if_convertible_phi_p (struct loop *loop, basic_block bb, tree phi) +if_convertible_phi_p (struct loop *loop, basic_block bb, gimple phi) { if (dump_file && (dump_flags & TDF_DETAILS)) { fprintf (dump_file, "-------------------------\n"); - print_generic_stmt (dump_file, phi, TDF_SLIM); + print_gimple_stmt (dump_file, phi, 0, TDF_SLIM); } - if (bb != loop->header && PHI_NUM_ARGS (phi) != 2) + if (bb != loop->header && gimple_phi_num_args (phi) != 2) { if (dump_file && (dump_flags & TDF_DETAILS)) fprintf (dump_file, "More than two phi node args.\n"); return false; } - if (!is_gimple_reg (SSA_NAME_VAR (PHI_RESULT (phi)))) + if (!is_gimple_reg (SSA_NAME_VAR (gimple_phi_result (phi)))) { imm_use_iterator imm_iter; use_operand_p use_p; - FOR_EACH_IMM_USE_FAST (use_p, imm_iter, PHI_RESULT (phi)) + + if (bb != loop->header) + { + if (dump_file && (dump_flags & TDF_DETAILS)) + fprintf (dump_file, "Virtual phi not on loop header.\n"); + return false; + } + FOR_EACH_IMM_USE_FAST (use_p, imm_iter, gimple_phi_result (phi)) { - if (TREE_CODE (USE_STMT (use_p)) == PHI_NODE) + if (gimple_code (USE_STMT (use_p)) == GIMPLE_PHI) { if (dump_file && (dump_flags & TDF_DETAILS)) fprintf (dump_file, "Difficult to handle this virtual phi.\n"); @@ -333,37 +348,32 @@ if_convertible_phi_p (struct loop *loop, basic_block bb, tree phi) return true; } -/* Return true, if M_EXPR is if-convertible. - GIMPLE_MODIFY_STMT is not if-convertible if, - - It is not movable. - - It could trap. +/* Return true when STMT is if-convertible. + + GIMPLE_ASSIGN statement is not if-convertible if, + - it is not movable, + - it could trap, - LHS is not var decl. - GIMPLE_MODIFY_STMT is part of block BB, which is inside loop LOOP. -*/ + GIMPLE_ASSIGN is part of block BB, which is inside loop LOOP. */ static bool -if_convertible_gimple_modify_stmt_p (struct loop *loop, basic_block bb, - tree m_expr) +if_convertible_gimple_assign_stmt_p (struct loop *loop, basic_block bb, + gimple stmt) { - tree lhs, rhs; - - if (TREE_CODE (m_expr) != GIMPLE_MODIFY_STMT) - return false; + tree lhs = gimple_assign_lhs (stmt); if (dump_file && (dump_flags & TDF_DETAILS)) { fprintf (dump_file, "-------------------------\n"); - print_generic_stmt (dump_file, m_expr, TDF_SLIM); + print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM); } - lhs = GIMPLE_STMT_OPERAND (m_expr, 0); - rhs = GIMPLE_STMT_OPERAND (m_expr, 1); - /* Some of these constrains might be too conservative. */ - if (stmt_ends_bb_p (m_expr) || stmt_ann (m_expr)->has_volatile_ops + if (stmt_ends_bb_p (stmt) + || gimple_has_volatile_ops (stmt) || (TREE_CODE (lhs) == SSA_NAME && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (lhs)) - || TREE_SIDE_EFFECTS (rhs)) + || gimple_has_side_effects (stmt)) { if (dump_file && (dump_flags & TDF_DETAILS)) fprintf (dump_file, "stmt not suitable for ifcvt\n"); @@ -372,65 +382,53 @@ if_convertible_gimple_modify_stmt_p (struct loop *loop, basic_block bb, /* See if it needs speculative loading or not. */ if (bb != loop->header - && tree_could_trap_p (GIMPLE_STMT_OPERAND (m_expr, 1))) + && gimple_assign_rhs_could_trap_p (stmt)) { if (dump_file && (dump_flags & TDF_DETAILS)) fprintf (dump_file, "tree could trap...\n"); return false; } - if (TREE_CODE (GIMPLE_STMT_OPERAND (m_expr, 1)) == CALL_EXPR) - { - if (dump_file && (dump_flags & TDF_DETAILS)) - fprintf (dump_file, "CALL_EXPR \n"); - return false; - } - - if (TREE_CODE (GIMPLE_STMT_OPERAND (m_expr, 0)) != SSA_NAME + if (TREE_CODE (lhs) != SSA_NAME && bb != loop->header && !bb_with_exit_edge_p (loop, bb)) { if (dump_file && (dump_flags & TDF_DETAILS)) { fprintf (dump_file, "LHS is not var\n"); - print_generic_stmt (dump_file, m_expr, TDF_SLIM); + print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM); } return false; } - return true; } /* Return true, iff STMT is if-convertible. Statement is if-convertible if, - - It is if-convertible GIMPLE_MODIFY_STMT - - IT is LABEL_EXPR or COND_EXPR. + - it is if-convertible GIMPLE_ASSGIN, + - it is GIMPLE_LABEL or GIMPLE_COND. STMT is inside block BB, which is inside loop LOOP. */ static bool -if_convertible_stmt_p (struct loop *loop, basic_block bb, tree stmt) +if_convertible_stmt_p (struct loop *loop, basic_block bb, gimple stmt) { - switch (TREE_CODE (stmt)) + switch (gimple_code (stmt)) { - case LABEL_EXPR: - break; + case GIMPLE_LABEL: + case GIMPLE_DEBUG: + case GIMPLE_COND: + return true; - case GIMPLE_MODIFY_STMT: - - if (!if_convertible_gimple_modify_stmt_p (loop, bb, stmt)) - return false; - break; - - case COND_EXPR: - break; + case GIMPLE_ASSIGN: + return if_convertible_gimple_assign_stmt_p (loop, bb, stmt); default: /* Don't know what to do with 'em so don't do anything. */ if (dump_file && (dump_flags & TDF_DETAILS)) { fprintf (dump_file, "don't know what to do\n"); - print_generic_stmt (dump_file, stmt, TDF_SLIM); + print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM); } return false; break; @@ -441,10 +439,10 @@ if_convertible_stmt_p (struct loop *loop, basic_block bb, tree stmt) /* Return true, iff BB is if-convertible. Note: This routine does _not_ check basic block statements and phis. - Basic block is not if-convertible if, - - Basic block is non-empty and it is after exit block (in BFS order). - - Basic block is after exit block but before latch. - - Basic block edge(s) is not normal. + Basic block is not if-convertible if: + - basic block is non-empty and it is after exit block (in BFS order), + - basic block is after exit block but before latch, + - basic block edge(s) is not normal. EXIT_BB_SEEN is true if basic block with exit edge is already seen. BB is inside loop LOOP. */ @@ -471,7 +469,7 @@ if_convertible_bb_p (struct loop *loop, basic_block bb, basic_block exit_bb) fprintf (dump_file, "non empty basic block after exit bb\n"); return false; } - else if (bb == loop->latch + else if (bb == loop->latch && bb != exit_bb && !dominated_by_p (CDI_DOMINATORS, bb, exit_bb)) { @@ -494,23 +492,176 @@ if_convertible_bb_p (struct loop *loop, basic_block bb, basic_block exit_bb) return true; } +/* Return TRUE iff, all pred blocks of BB are visited. + Bitmap VISITED keeps history of visited blocks. */ + +static bool +pred_blocks_visited_p (basic_block bb, bitmap *visited) +{ + edge e; + edge_iterator ei; + FOR_EACH_EDGE (e, ei, bb->preds) + if (!bitmap_bit_p (*visited, e->src->index)) + return false; + + return true; +} + +/* Get body of a LOOP in suitable order for if-conversion. It is + caller's responsibility to deallocate basic block list. + If-conversion suitable order is, breadth first sort (BFS) order + with an additional constraint: select a block only if all its + predecessors are already selected. */ + +static basic_block * +get_loop_body_in_if_conv_order (const struct loop *loop) +{ + basic_block *blocks, *blocks_in_bfs_order; + basic_block bb; + bitmap visited; + unsigned int index = 0; + unsigned int visited_count = 0; + + gcc_assert (loop->num_nodes); + gcc_assert (loop->latch != EXIT_BLOCK_PTR); + + blocks = XCNEWVEC (basic_block, loop->num_nodes); + visited = BITMAP_ALLOC (NULL); + + blocks_in_bfs_order = get_loop_body_in_bfs_order (loop); + + index = 0; + while (index < loop->num_nodes) + { + bb = blocks_in_bfs_order [index]; + + if (bb->flags & BB_IRREDUCIBLE_LOOP) + { + free (blocks_in_bfs_order); + BITMAP_FREE (visited); + free (blocks); + return NULL; + } + + if (!bitmap_bit_p (visited, bb->index)) + { + if (pred_blocks_visited_p (bb, &visited) + || bb == loop->header) + { + /* This block is now visited. */ + bitmap_set_bit (visited, bb->index); + blocks[visited_count++] = bb; + } + } + + index++; + + if (index == loop->num_nodes + && visited_count != loop->num_nodes) + /* Not done yet. */ + index = 0; + } + free (blocks_in_bfs_order); + BITMAP_FREE (visited); + return blocks; +} + /* Return true, iff LOOP is if-convertible. - LOOP is if-convertible if, - - It is innermost. - - It has two or more basic blocks. - - It has only one exit. - - Loop header is not the exit edge. - - If its basic blocks and phi nodes are if convertible. See above for + LOOP is if-convertible if: + - it is innermost, + - it has two or more basic blocks, + - it has only one exit, + - loop header is not the exit edge, + - if its basic blocks and phi nodes are if convertible. See above for more info. - FOR_VECTORIZER enables vectorizer specific checks. For example, support - for vector conditions, data dependency checks etc.. (Not implemented yet). */ + FOR_VECTORIZER enables vectorizer specific checks, for example, support + for vector conditions, data dependency checks, etc. + (Not implemented yet). */ + +static bool +pred_blocks_visited_p (basic_block bb, bitmap *visited) +{ + edge e; + edge_iterator ei; + FOR_EACH_EDGE (e, ei, bb->preds) + if (!bitmap_bit_p (*visited, e->src->index)) + return false; + + return true; +} + +/* Get body of a LOOP in suitable order for if-conversion. It is + caller's responsibility to deallocate basic block list. + If-conversion suitable order is, breadth first sort (BFS) order + with an additional constraint: select a block only if all its + predecessors are already selected. */ + +static basic_block * +get_loop_body_in_if_conv_order (const struct loop *loop) +{ + basic_block *blocks, *blocks_in_bfs_order; + basic_block bb; + bitmap visited; + unsigned int index = 0; + unsigned int visited_count = 0; + + gcc_assert (loop->num_nodes); + gcc_assert (loop->latch != EXIT_BLOCK_PTR); + + blocks = XCNEWVEC (basic_block, loop->num_nodes); + visited = BITMAP_ALLOC (NULL); + + blocks_in_bfs_order = get_loop_body_in_bfs_order (loop); + + index = 0; + while (index < loop->num_nodes) + { + bb = blocks_in_bfs_order [index]; + + if (bb->flags & BB_IRREDUCIBLE_LOOP) + { + free (blocks_in_bfs_order); + BITMAP_FREE (visited); + free (blocks); + return NULL; + } + + if (!bitmap_bit_p (visited, bb->index)) + { + if (pred_blocks_visited_p (bb, &visited) + || bb == loop->header) + { + /* This block is now visited. */ + bitmap_set_bit (visited, bb->index); + blocks[visited_count++] = bb; + } + } + + index++; + + if (index == loop->num_nodes + && visited_count != loop->num_nodes) + /* Not done yet. */ + index = 0; + } + free (blocks_in_bfs_order); + BITMAP_FREE (visited); + return blocks; +} + +/* Return true when LOOP is if-convertible. + LOOP is if-convertible if: + - it is innermost, + - it has two or more basic blocks, + - it has only one exit, + - loop header is not the exit edge, + - if its basic blocks and phi nodes are if convertible. */ static bool -if_convertible_loop_p (struct loop *loop, bool for_vectorizer ATTRIBUTE_UNUSED) +if_convertible_loop_p (struct loop *loop) { - tree phi; basic_block bb; - block_stmt_iterator itr; + gimple_stmt_iterator itr; unsigned int i; edge e; edge_iterator ei; @@ -570,31 +721,24 @@ if_convertible_loop_p (struct loop *loop, bool for_vectorizer ATTRIBUTE_UNUSED) if (!if_convertible_bb_p (loop, bb, exit_bb)) return false; - /* Check statements. */ - for (itr = bsi_start (bb); !bsi_end_p (itr); bsi_next (&itr)) - if (!if_convertible_stmt_p (loop, bb, bsi_stmt (itr))) + for (itr = gsi_start_bb (bb); !gsi_end_p (itr); gsi_next (&itr)) + if (!if_convertible_stmt_p (loop, bb, gsi_stmt (itr))) return false; - /* ??? Check data dependency for vectorizer. */ - /* What about phi nodes ? */ - phi = phi_nodes (bb); + itr = gsi_start_phis (bb); - /* Clear aux field of incoming edges to a bb with a phi node. */ - if (phi) + if (!gsi_end_p (itr)) FOR_EACH_EDGE (e, ei, bb->preds) e->aux = NULL; - /* Check statements. */ - for (; phi; phi = PHI_CHAIN (phi)) - if (!if_convertible_phi_p (loop, bb, phi)) + for (; !gsi_end_p (itr); gsi_next (&itr)) + if (!if_convertible_phi_p (loop, bb, gsi_stmt (itr))) return false; if (bb_with_exit_edge_p (loop, bb)) exit_bb = bb; } - /* OK. Did not find any potential issues so go ahead in if-convert - this loop. Now there is no looking back. */ if (dump_file) fprintf (dump_file,"Applying if-conversion\n"); @@ -602,66 +746,8 @@ if_convertible_loop_p (struct loop *loop, bool for_vectorizer ATTRIBUTE_UNUSED) return true; } -/* Add condition COND into predicate list of basic block BB. */ - -static void -add_to_predicate_list (basic_block bb, tree new_cond) -{ - tree cond = bb->aux; - - if (cond) - cond = fold_build2 (TRUTH_OR_EXPR, boolean_type_node, - unshare_expr (cond), new_cond); - else - cond = new_cond; - - bb->aux = cond; -} - -/* Add condition COND into BB's predicate list. PREV_COND is - existing condition. */ - -static tree -add_to_dst_predicate_list (struct loop * loop, edge e, - tree prev_cond, tree cond, - block_stmt_iterator *bsi) -{ - tree new_cond = NULL_TREE; - - if (!flow_bb_inside_loop_p (loop, e->dest)) - return NULL_TREE; - - if (prev_cond == boolean_true_node || !prev_cond) - new_cond = unshare_expr (cond); - else - { - tree tmp; - tree tmp_stmt = NULL_TREE; - - prev_cond = force_gimple_operand_bsi (bsi, unshare_expr (prev_cond), - true, NULL, true, BSI_SAME_STMT); - - cond = force_gimple_operand_bsi (bsi, unshare_expr (cond), - true, NULL, true, BSI_SAME_STMT); - - /* Add the condition to aux field of the edge. In case edge - destination is a PHI node, this condition will be ANDed with - block predicate to construct complete condition. */ - e->aux = cond; - - /* new_cond == prev_cond AND cond */ - tmp = build2 (TRUTH_AND_EXPR, boolean_type_node, - unshare_expr (prev_cond), cond); - tmp_stmt = ifc_temp_var (boolean_type_node, tmp); - bsi_insert_before (bsi, tmp_stmt, BSI_SAME_STMT); - new_cond = GIMPLE_STMT_OPERAND (tmp_stmt, 0); - } - add_to_predicate_list (e->dest, new_cond); - return new_cond; -} - /* During if-conversion aux field from basic block structure is used to hold - predicate list. Clean each basic block's predicate list for the given LOOP. + predicate list. Clean each basic block's predicate list for the given LOOP. Also clean aux field of successor edges, used to hold true and false condition from conditional expression. */ @@ -684,13 +770,13 @@ clean_predicate_lists (struct loop *loop) } /* Basic block BB has two predecessors. Using predecessor's aux field, set - appropriate condition COND for the PHI node replacement. Return true block + appropriate condition COND for the PHI node replacement. Return true block whose phi arguments are selected when cond is true. */ static basic_block -find_phi_replacement_condition (struct loop *loop, +find_phi_replacement_condition (struct loop *loop, basic_block bb, tree *cond, - block_stmt_iterator *bsi) + gimple_stmt_iterator *gsi) { edge first_edge, second_edge; tree tmp_cond; @@ -706,7 +792,7 @@ find_phi_replacement_condition (struct loop *loop, S2: x = c ? b : a; S2 is preferred over S1. Make 'b' first_bb and use its condition. - + 2) Do not make loop header first_bb. 3) @@ -717,14 +803,16 @@ find_phi_replacement_condition (struct loop *loop, S3: x = (c == d) ? b : a; - S3 is preferred over S1 and S2*, Make 'b' first_bb and use + S3 is preferred over S1 and S2*, Make 'b' first_bb and use its condition. 4) If pred B is dominated by pred A then use pred B's condition. See PR23115. */ /* Select condition that is not TRUTH_NOT_EXPR. */ - tmp_cond = (first_edge->src)->aux; + tmp_cond = (tree) (first_edge->src)->aux; + gcc_assert (tmp_cond); + if (TREE_CODE (tmp_cond) == TRUTH_NOT_EXPR) { edge tmp_edge; @@ -740,17 +828,15 @@ find_phi_replacement_condition (struct loop *loop, || dominated_by_p (CDI_DOMINATORS, second_edge->src, first_edge->src)) { - *cond = (second_edge->src)->aux; + *cond = (tree) (second_edge->src)->aux; - /* If there is a condition on an incoming edge, - AND it with the incoming bb predicate. */ + /* If there is a condition on an incoming edge, add it to the + incoming bb predicate. */ if (second_edge->aux) *cond = build2 (TRUTH_AND_EXPR, boolean_type_node, - *cond, second_edge->aux); + *cond, (tree) second_edge->aux); if (TREE_CODE (*cond) == TRUTH_NOT_EXPR) - /* We can be smart here and choose inverted - condition without switching bbs. */ *cond = invert_truthvalue (*cond); else /* Select non loop header bb. */ @@ -758,31 +844,30 @@ find_phi_replacement_condition (struct loop *loop, } else { - /* FIRST_BB is not loop header */ - *cond = (first_edge->src)->aux; + *cond = (tree) (first_edge->src)->aux; - /* If there is a condition on an incoming edge, - AND it with the incoming bb predicate. */ + /* If there is a condition on an incoming edge, add it to the + incoming bb predicate. */ if (first_edge->aux) *cond = build2 (TRUTH_AND_EXPR, boolean_type_node, - *cond, first_edge->aux); + *cond, (tree) first_edge->aux); } - /* Create temp. for the condition. Vectorizer prefers to have gimple - value as condition. Various targets use different means to communicate - condition in vector compare operation. Using gimple value allows - compiler to emit vector compare and select RTL without exposing - compare's result. */ - *cond = force_gimple_operand_bsi (bsi, unshare_expr (*cond), + /* Gimplify the condition: the vectorizer prefers to have gimple + values as conditions. Various targets use different means to + communicate conditions in vector compare operations. Using a + gimple value allows the compiler to emit vector compare and + select RTL without exposing compare's result. */ + *cond = force_gimple_operand_gsi (gsi, unshare_expr (*cond), false, NULL_TREE, - true, BSI_SAME_STMT); + true, GSI_SAME_STMT); if (!is_gimple_reg (*cond) && !is_gimple_condexpr (*cond)) { - tree new_stmt; + gimple new_stmt; new_stmt = ifc_temp_var (TREE_TYPE (*cond), unshare_expr (*cond)); - bsi_insert_before (bsi, new_stmt, BSI_SAME_STMT); - *cond = GIMPLE_STMT_OPERAND (new_stmt, 0); + gsi_insert_before (gsi, new_stmt, GSI_SAME_STMT); + *cond = gimple_assign_lhs (new_stmt); } gcc_assert (*cond); @@ -790,45 +875,43 @@ find_phi_replacement_condition (struct loop *loop, return first_edge->src; } +/* Replace PHI node with conditional modify expr using COND. This + routine does not handle PHI nodes with more than two arguments. -/* Replace PHI node with conditional modify expr using COND. - This routine does not handle PHI nodes with more than two arguments. For example, S1: A = PHI src == true_bb) { - arg_0 = PHI_ARG_DEF (phi, 1); - arg_1 = PHI_ARG_DEF (phi, 0); + arg_0 = gimple_phi_arg_def (phi, 1); + arg_1 = gimple_phi_arg_def (phi, 0); } else { - arg_0 = PHI_ARG_DEF (phi, 0); - arg_1 = PHI_ARG_DEF (phi, 1); + arg_0 = gimple_phi_arg_def (phi, 0); + arg_1 = gimple_phi_arg_def (phi, 1); } /* Build new RHS using selected condition and arguments. */ @@ -836,25 +919,20 @@ replace_phi_with_cond_gimple_modify_stmt (tree phi, tree cond, unshare_expr (cond), unshare_expr (arg_0), unshare_expr (arg_1)); - /* Create new MODIFY expression using RHS. */ - new_stmt = build_gimple_modify_stmt (unshare_expr (PHI_RESULT (phi)), rhs); - - /* Make new statement definition of the original phi result. */ - SSA_NAME_DEF_STMT (PHI_RESULT (phi)) = new_stmt; - - /* Insert using iterator. */ - bsi_insert_before (bsi, new_stmt, BSI_SAME_STMT); + new_stmt = gimple_build_assign (unshare_expr (PHI_RESULT (phi)), rhs); + SSA_NAME_DEF_STMT (gimple_phi_result (phi)) = new_stmt; + gsi_insert_before (gsi, new_stmt, GSI_SAME_STMT); update_stmt (new_stmt); if (dump_file && (dump_flags & TDF_DETAILS)) { fprintf (dump_file, "new phi replacement stmt\n"); - print_generic_stmt (dump_file, new_stmt, TDF_SLIM); + print_gimple_stmt (dump_file, new_stmt, 0, TDF_SLIM); } } -/* Process phi nodes for the given LOOP. Replace phi nodes with cond - modify expr. */ +/* Process phi nodes for the given LOOP. Replace phi nodes with + conditional modify expressions. */ static void process_phi_nodes (struct loop *loop) @@ -863,39 +941,38 @@ process_phi_nodes (struct loop *loop) unsigned int orig_loop_num_nodes = loop->num_nodes; unsigned int i; - /* Replace phi nodes with cond. modify expr. */ for (i = 1; i < orig_loop_num_nodes; i++) { - tree phi, cond; - block_stmt_iterator bsi; + gimple phi; + tree cond = NULL_TREE; + gimple_stmt_iterator gsi, phi_gsi; basic_block true_bb = NULL; bb = ifc_bbs[i]; if (bb == loop->header) continue; - phi = phi_nodes (bb); - bsi = bsi_after_labels (bb); + phi_gsi = gsi_start_phis (bb); + gsi = gsi_after_labels (bb); - /* BB has two predecessors. Using predecessor's aux field, set + /* BB has two predecessors. Using predecessor's aux field, set appropriate condition for the PHI node replacement. */ - if (phi) - true_bb = find_phi_replacement_condition (loop, bb, &cond, &bsi); + if (!gsi_end_p (phi_gsi)) + true_bb = find_phi_replacement_condition (loop, bb, &cond, &gsi); - while (phi) + while (!gsi_end_p (phi_gsi)) { - tree next = PHI_CHAIN (phi); - replace_phi_with_cond_gimple_modify_stmt (phi, cond, true_bb, &bsi); + phi = gsi_stmt (phi_gsi); + replace_phi_with_cond_gimple_assign_stmt (phi, cond, true_bb, &gsi); release_phi_node (phi); - phi = next; + gsi_next (&phi_gsi); } - set_phi_nodes (bb, NULL_TREE); + set_phi_nodes (bb, NULL); } - return; } -/* Combine all basic block from the given LOOP into one or two super - basic block. Replace PHI nodes with conditional modify expression. */ +/* Combine all the basic blocks from LOOP into one or two super basic + blocks. Replace PHI nodes with conditional modify expressions. */ static void combine_blocks (struct loop *loop) @@ -909,8 +986,8 @@ combine_blocks (struct loop *loop) /* Process phi nodes to prepare blocks for merge. */ process_phi_nodes (loop); - /* Merge basic blocks. First remove all the edges in the loop, except - for those from the exit block. */ + /* Merge basic blocks: first remove all the edges in the loop, + except for those from the exit block. */ exit_bb = NULL; for (i = 0; i < orig_loop_num_nodes; i++) { @@ -940,7 +1017,7 @@ combine_blocks (struct loop *loop) { if (exit_bb != loop->header) { - /* Connect this node with loop header. */ + /* Connect this node to loop header. */ make_edge (loop->header, exit_bb, EDGE_FALLTHRU); set_immediate_dominator (CDI_DOMINATORS, exit_bb, loop->header); } @@ -955,7 +1032,7 @@ combine_blocks (struct loop *loop) } else { - /* If the loop does not have exit then reconnect header and latch. */ + /* If the loop does not have an exit, reconnect header and latch. */ make_edge (loop->header, loop->latch, EDGE_FALLTHRU); set_immediate_dominator (CDI_DOMINATORS, loop->latch, loop->header); } @@ -963,8 +1040,8 @@ combine_blocks (struct loop *loop) merge_target_bb = loop->header; for (i = 1; i < orig_loop_num_nodes; i++) { - block_stmt_iterator bsi; - tree_stmt_iterator last; + gimple_stmt_iterator gsi; + gimple_stmt_iterator last; bb = ifc_bbs[i]; @@ -972,27 +1049,27 @@ combine_blocks (struct loop *loop) continue; /* Remove labels and make stmts member of loop->header. */ - for (bsi = bsi_start (bb); !bsi_end_p (bsi); ) + for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); ) { - if (TREE_CODE (bsi_stmt (bsi)) == LABEL_EXPR) - bsi_remove (&bsi, true); + if (gimple_code (gsi_stmt (gsi)) == GIMPLE_LABEL) + gsi_remove (&gsi, true); else { - set_bb_for_stmt (bsi_stmt (bsi), merge_target_bb); - bsi_next (&bsi); + gimple_set_bb (gsi_stmt (gsi), merge_target_bb); + gsi_next (&gsi); } } /* Update stmt list. */ - last = tsi_last (bb_stmt_list (merge_target_bb)); - tsi_link_after (&last, bb_stmt_list (bb), TSI_NEW_STMT); - set_bb_stmt_list (bb, NULL); + last = gsi_last_bb (merge_target_bb); + gsi_insert_seq_after (&last, bb_seq (bb), GSI_NEW_STMT); + set_bb_seq (bb, NULL); delete_basic_block (bb); } /* Now if possible, merge loop header and block with exit edge. - This reduces number of basic blocks to 2. Auto vectorizer addresses + This reduces number of basic blocks to 2. Auto vectorizer addresses loops with two nodes only. FIXME: Use cleanup_tree_cfg(). */ if (exit_bb && exit_bb != loop->header @@ -1000,125 +1077,85 @@ combine_blocks (struct loop *loop) merge_blocks (loop->header, exit_bb); } -/* Make new temp variable of type TYPE. Add GIMPLE_MODIFY_STMT to assign EXP - to the new variable. */ - -static tree -ifc_temp_var (tree type, tree exp) -{ - const char *name = "_ifc_"; - tree var, stmt, new_name; - - if (is_gimple_reg (exp)) - return exp; - - /* Create new temporary variable. */ - var = create_tmp_var (type, name); - add_referenced_var (var); - - /* Build new statement to assign EXP to new variable. */ - stmt = build_gimple_modify_stmt (var, exp); - - /* Get SSA name for the new variable and set make new statement - its definition statement. */ - new_name = make_ssa_name (var, stmt); - GIMPLE_STMT_OPERAND (stmt, 0) = new_name; - SSA_NAME_DEF_STMT (new_name) = stmt; - - return stmt; -} - - -/* Return TRUE iff, all pred blocks of BB are visited. - Bitmap VISITED keeps history of visited blocks. */ +/* Main entry point. Apply if-conversion to the LOOP. Return true if + successful otherwise return false. If false is returned then loop + remains unchanged. FOR_VECTORIZER is a boolean flag. It indicates + whether if-conversion is used for vectorizer or not. If it is used + for vectorizer, additional checks are used. (Vectorization checks + are not yet implemented). */ static bool -pred_blocks_visited_p (basic_block bb, bitmap *visited) -{ - edge e; - edge_iterator ei; - FOR_EACH_EDGE (e, ei, bb->preds) - if (!bitmap_bit_p (*visited, e->src->index)) - return false; - - return true; -} - -/* Get body of a LOOP in suitable order for if-conversion. - It is caller's responsibility to deallocate basic block - list. If-conversion suitable order is, BFS order with one - additional constraint. Select block in BFS block, if all - pred are already selected. */ - -static basic_block * -get_loop_body_in_if_conv_order (const struct loop *loop) +tree_if_conversion (struct loop *loop, bool for_vectorizer) { - basic_block *blocks, *blocks_in_bfs_order; basic_block bb; - bitmap visited; - unsigned int index = 0; - unsigned int visited_count = 0; - - gcc_assert (loop->num_nodes); - gcc_assert (loop->latch != EXIT_BLOCK_PTR); - - blocks = XCNEWVEC (basic_block, loop->num_nodes); - visited = BITMAP_ALLOC (NULL); + gimple_stmt_iterator itr; + unsigned int i; - blocks_in_bfs_order = get_loop_body_in_bfs_order (loop); + ifc_bbs = NULL; - index = 0; - while (index < loop->num_nodes) + /* If-conversion is not appropriate for all loops. First, check if + loop is if-convertible or not. */ + if (!if_convertible_loop_p (loop, for_vectorizer)) { - bb = blocks_in_bfs_order [index]; - - if (bb->flags & BB_IRREDUCIBLE_LOOP) + if (dump_file && (dump_flags & TDF_DETAILS)) + fprintf (dump_file,"-------------------------\n"); + if (ifc_bbs) { - free (blocks_in_bfs_order); - BITMAP_FREE (visited); - free (blocks); - return NULL; + free (ifc_bbs); + ifc_bbs = NULL; } - if (!bitmap_bit_p (visited, bb->index)) + free_dominance_info (CDI_POST_DOMINATORS); + return false; + } + + /* Do actual work now. */ + for (i = 0; i < loop->num_nodes; i++) + { + tree cond; + + bb = ifc_bbs [i]; + + /* Update condition using predicate list. */ + cond = (tree) bb->aux; + + /* Process all statements in this basic block. + Remove conditional expression, if any, and annotate + destination basic block(s) appropriately. */ + for (itr = gsi_start_bb (bb); !gsi_end_p (itr); /* empty */) { - if (pred_blocks_visited_p (bb, &visited) - || bb == loop->header) - { - /* This block is now visited. */ - bitmap_set_bit (visited, bb->index); - blocks[visited_count++] = bb; - } + gimple t = gsi_stmt (itr); + cond = tree_if_convert_stmt (loop, t, cond, &itr); + if (!gsi_end_p (itr)) + gsi_next (&itr); } - index++; - if (index == loop->num_nodes - && visited_count != loop->num_nodes) + + /* If current bb has only one successor, then consider it as an + unconditional goto. */ + if (single_succ_p (bb)) { - /* Not done yet. */ - index = 0; + basic_block bb_n = single_succ (bb); + + /* Successor bb inherits predicate of its predecessor. If there + is no predicate in predecessor bb, then consider successor bb + as always executed. */ + if (cond == NULL_TREE) + cond = boolean_true_node; + + add_to_predicate_list (bb_n, cond); } } - free (blocks_in_bfs_order); - BITMAP_FREE (visited); - return blocks; -} -/* Return true if one of the basic block BB edge is exit of LOOP. */ - -static bool -bb_with_exit_edge_p (struct loop *loop, basic_block bb) -{ - edge e; - edge_iterator ei; - bool exit_edge_found = false; + /* Now, all statements are if-converted and basic blocks are + annotated appropriately. Combine all basic block into one huge + basic block. */ + combine_blocks (loop); - FOR_EACH_EDGE (e, ei, bb->succs) - if (loop_exit_edge_p (loop, e)) - { - exit_edge_found = true; - break; - } + /* clean up */ + clean_predicate_lists (loop); + free (ifc_bbs); + ifc_bbs = NULL; - return exit_edge_found; + return true; } /* Tree if-conversion pass management. */ @@ -1133,9 +1170,8 @@ main_tree_if_conversion (void) return 0; FOR_EACH_LOOP (li, loop, 0) - { - tree_if_conversion (loop, true); - } + tree_if_conversion (loop); + return 0; } @@ -1145,20 +1181,22 @@ gate_tree_if_conversion (void) return flag_tree_vectorize != 0; } -struct tree_opt_pass pass_if_conversion = +struct gimple_opt_pass pass_if_conversion = { + { + GIMPLE_PASS, "ifcvt", /* name */ gate_tree_if_conversion, /* gate */ main_tree_if_conversion, /* execute */ NULL, /* sub */ NULL, /* next */ 0, /* static_pass_number */ - 0, /* tv_id */ - PROP_cfg | PROP_ssa | PROP_alias, /* properties_required */ + TV_NONE, /* tv_id */ + PROP_cfg | PROP_ssa, /* properties_required */ 0, /* properties_provided */ 0, /* properties_destroyed */ 0, /* todo_flags_start */ - TODO_dump_func | TODO_verify_loops | TODO_verify_stmts | TODO_verify_flow, + TODO_dump_func | TODO_verify_stmts | TODO_verify_flow /* todo_flags_finish */ - 0 /* letter */ + } };