diff options
Diffstat (limited to 'gcc-4.2.1-5666.3/gcc/tree-ssa-phiopt.c')
| -rw-r--r-- | gcc-4.2.1-5666.3/gcc/tree-ssa-phiopt.c | 1022 |
1 files changed, 0 insertions, 1022 deletions
diff --git a/gcc-4.2.1-5666.3/gcc/tree-ssa-phiopt.c b/gcc-4.2.1-5666.3/gcc/tree-ssa-phiopt.c deleted file mode 100644 index edad768d8..000000000 --- a/gcc-4.2.1-5666.3/gcc/tree-ssa-phiopt.c +++ /dev/null @@ -1,1022 +0,0 @@ -/* Optimization of PHI nodes by converting them into straightline code. - Copyright (C) 2004, 2005 Free Software Foundation, Inc. - -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 version. - -GCC is distributed in the hope that it will be useful, but WITHOUT -ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or -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. */ - -#include "config.h" -#include "system.h" -#include "coretypes.h" -#include "tm.h" -#include "ggc.h" -#include "tree.h" -#include "rtl.h" -#include "flags.h" -#include "tm_p.h" -#include "basic-block.h" -#include "timevar.h" -#include "diagnostic.h" -#include "tree-flow.h" -#include "tree-pass.h" -#include "tree-dump.h" -#include "langhooks.h" - -static unsigned int tree_ssa_phiopt (void); -static bool conditional_replacement (basic_block, basic_block, - edge, edge, tree, tree, tree); -static bool value_replacement (basic_block, basic_block, - edge, edge, tree, tree, tree); -static bool minmax_replacement (basic_block, basic_block, - edge, edge, tree, tree, tree); -static bool abs_replacement (basic_block, basic_block, - edge, edge, tree, tree, tree); -static void replace_phi_edge_with_variable (basic_block, edge, tree, tree); -static basic_block *blocks_in_phiopt_order (void); - -/* This pass tries to replaces an if-then-else block with an - assignment. We have four kinds of transformations. Some of these - transformations are also performed by the ifcvt RTL optimizer. - - Conditional Replacement - ----------------------- - - This transformation, implemented in conditional_replacement, - replaces - - bb0: - if (cond) goto bb2; else goto bb1; - bb1: - bb2: - x = PHI <0 (bb1), 1 (bb0), ...>; - - with - - bb0: - x' = cond; - goto bb2; - bb2: - x = PHI <x' (bb0), ...>; - - We remove bb1 as it becomes unreachable. This occurs often due to - gimplification of conditionals. - - Value Replacement - ----------------- - - This transformation, implemented in value_replacement, replaces - - bb0: - if (a != b) goto bb2; else goto bb1; - bb1: - bb2: - x = PHI <a (bb1), b (bb0), ...>; - - with - - bb0: - bb2: - x = PHI <b (bb0), ...>; - - This opportunity can sometimes occur as a result of other - optimizations. - - ABS Replacement - --------------- - - This transformation, implemented in abs_replacement, replaces - - bb0: - if (a >= 0) goto bb2; else goto bb1; - bb1: - x = -a; - bb2: - x = PHI <x (bb1), a (bb0), ...>; - - with - - bb0: - x' = ABS_EXPR< a >; - bb2: - x = PHI <x' (bb0), ...>; - - MIN/MAX Replacement - ------------------- - - This transformation, minmax_replacement replaces - - bb0: - if (a <= b) goto bb2; else goto bb1; - bb1: - bb2: - x = PHI <b (bb1), a (bb0), ...>; - - with - - bb0: - x' = MIN_EXPR (a, b) - bb2: - x = PHI <x' (bb0), ...>; - - A similar transformation is done for MAX_EXPR. */ - -static unsigned int -tree_ssa_phiopt (void) -{ - basic_block bb; - basic_block *bb_order; - unsigned n, i; - bool cfgchanged = false; - - /* Search every basic block for COND_EXPR we may be able to optimize. - - We walk the blocks in order that guarantees that a block with - a single predecessor is processed before the predecessor. - This ensures that we collapse inner ifs before visiting the - outer ones, and also that we do not try to visit a removed - block. */ - bb_order = blocks_in_phiopt_order (); - n = n_basic_blocks - NUM_FIXED_BLOCKS; - - for (i = 0; i < n; i++) - { - tree cond_expr; - tree phi; - basic_block bb1, bb2; - edge e1, e2; - tree arg0, arg1; - - bb = bb_order[i]; - - cond_expr = last_stmt (bb); - /* Check to see if the last statement is a COND_EXPR. */ - if (!cond_expr - || TREE_CODE (cond_expr) != COND_EXPR) - continue; - - e1 = EDGE_SUCC (bb, 0); - bb1 = e1->dest; - e2 = EDGE_SUCC (bb, 1); - bb2 = e2->dest; - - /* We cannot do the optimization on abnormal edges. */ - if ((e1->flags & EDGE_ABNORMAL) != 0 - || (e2->flags & EDGE_ABNORMAL) != 0) - continue; - - /* If either bb1's succ or bb2 or bb2's succ is non NULL. */ - if (EDGE_COUNT (bb1->succs) == 0 - || bb2 == NULL - || EDGE_COUNT (bb2->succs) == 0) - continue; - - /* Find the bb which is the fall through to the other. */ - if (EDGE_SUCC (bb1, 0)->dest == bb2) - ; - else if (EDGE_SUCC (bb2, 0)->dest == bb1) - { - basic_block bb_tmp = bb1; - edge e_tmp = e1; - bb1 = bb2; - bb2 = bb_tmp; - e1 = e2; - e2 = e_tmp; - } - else - continue; - - e1 = EDGE_SUCC (bb1, 0); - - /* Make sure that bb1 is just a fall through. */ - if (!single_succ_p (bb1) - || (e1->flags & EDGE_FALLTHRU) == 0) - continue; - - /* Also make sure that bb1 only have one predecessor and that it - is bb. */ - if (!single_pred_p (bb1) - || single_pred (bb1) != bb) - continue; - - phi = phi_nodes (bb2); - - /* Check to make sure that there is only one PHI node. - TODO: we could do it with more than one iff the other PHI nodes - have the same elements for these two edges. */ - if (!phi || PHI_CHAIN (phi) != NULL) - continue; - - arg0 = PHI_ARG_DEF_TREE (phi, e1->dest_idx); - arg1 = PHI_ARG_DEF_TREE (phi, e2->dest_idx); - - /* Something is wrong if we cannot find the arguments in the PHI - node. */ - gcc_assert (arg0 != NULL && arg1 != NULL); - - /* Do the replacement of conditional if it can be done. */ - if (conditional_replacement (bb, bb1, e1, e2, phi, arg0, arg1)) - cfgchanged = true; - else if (value_replacement (bb, bb1, e1, e2, phi, arg0, arg1)) - cfgchanged = true; - else if (abs_replacement (bb, bb1, e1, e2, phi, arg0, arg1)) - cfgchanged = true; - else if (minmax_replacement (bb, bb1, e1, e2, phi, arg0, arg1)) - cfgchanged = true; - } - - free (bb_order); - - /* If the CFG has changed, we should cleanup the CFG. */ - return cfgchanged ? TODO_cleanup_cfg : 0; -} - -/* Returns the list of basic blocks in the function in an order that guarantees - that if a block X has just a single predecessor Y, then Y is after X in the - ordering. */ - -static basic_block * -blocks_in_phiopt_order (void) -{ - basic_block x, y; - basic_block *order = XNEWVEC (basic_block, n_basic_blocks); - unsigned n = n_basic_blocks - NUM_FIXED_BLOCKS; - unsigned np, i; - sbitmap visited = sbitmap_alloc (last_basic_block); - -#define MARK_VISITED(BB) (SET_BIT (visited, (BB)->index)) -#define VISITED_P(BB) (TEST_BIT (visited, (BB)->index)) - - sbitmap_zero (visited); - - MARK_VISITED (ENTRY_BLOCK_PTR); - FOR_EACH_BB (x) - { - if (VISITED_P (x)) - continue; - - /* Walk the predecessors of x as long as they have precisely one - predecessor and add them to the list, so that they get stored - after x. */ - for (y = x, np = 1; - single_pred_p (y) && !VISITED_P (single_pred (y)); - y = single_pred (y)) - np++; - for (y = x, i = n - np; - single_pred_p (y) && !VISITED_P (single_pred (y)); - y = single_pred (y), i++) - { - order[i] = y; - MARK_VISITED (y); - } - order[i] = y; - MARK_VISITED (y); - - gcc_assert (i == n - 1); - n -= np; - } - - sbitmap_free (visited); - gcc_assert (n == 0); - return order; - -#undef MARK_VISITED -#undef VISITED_P -} - -/* Return TRUE if block BB has no executable statements, otherwise return - FALSE. */ -bool -empty_block_p (basic_block bb) -{ - block_stmt_iterator bsi; - - /* BB must have no executable statements. */ - bsi = bsi_start (bb); - while (!bsi_end_p (bsi) - && (TREE_CODE (bsi_stmt (bsi)) == LABEL_EXPR - || IS_EMPTY_STMT (bsi_stmt (bsi)))) - bsi_next (&bsi); - - if (!bsi_end_p (bsi)) - return false; - - return true; -} - -/* Replace PHI node element whose edge is E in block BB with variable NEW. - Remove the edge from COND_BLOCK which does not lead to BB (COND_BLOCK - is known to have two edges, one of which must reach BB). */ - -static void -replace_phi_edge_with_variable (basic_block cond_block, - edge e, tree phi, tree new) -{ - basic_block bb = bb_for_stmt (phi); - basic_block block_to_remove; - block_stmt_iterator bsi; - - /* Change the PHI argument to new. */ - SET_USE (PHI_ARG_DEF_PTR (phi, e->dest_idx), new); - - /* Remove the empty basic block. */ - if (EDGE_SUCC (cond_block, 0)->dest == bb) - { - EDGE_SUCC (cond_block, 0)->flags |= EDGE_FALLTHRU; - EDGE_SUCC (cond_block, 0)->flags &= ~(EDGE_TRUE_VALUE | EDGE_FALSE_VALUE); - EDGE_SUCC (cond_block, 0)->probability = REG_BR_PROB_BASE; - EDGE_SUCC (cond_block, 0)->count += EDGE_SUCC (cond_block, 1)->count; - - block_to_remove = EDGE_SUCC (cond_block, 1)->dest; - } - else - { - EDGE_SUCC (cond_block, 1)->flags |= EDGE_FALLTHRU; - EDGE_SUCC (cond_block, 1)->flags - &= ~(EDGE_TRUE_VALUE | EDGE_FALSE_VALUE); - EDGE_SUCC (cond_block, 1)->probability = REG_BR_PROB_BASE; - EDGE_SUCC (cond_block, 1)->count += EDGE_SUCC (cond_block, 0)->count; - - block_to_remove = EDGE_SUCC (cond_block, 0)->dest; - } - delete_basic_block (block_to_remove); - - /* Eliminate the COND_EXPR at the end of COND_BLOCK. */ - bsi = bsi_last (cond_block); - bsi_remove (&bsi, true); - - if (dump_file && (dump_flags & TDF_DETAILS)) - fprintf (dump_file, - "COND_EXPR in block %d and PHI in block %d converted to straightline code.\n", - cond_block->index, - bb->index); -} - -/* The function conditional_replacement does the main work of doing the - conditional replacement. Return true if the replacement is done. - Otherwise return false. - BB is the basic block where the replacement is going to be done on. ARG0 - is argument 0 from PHI. Likewise for ARG1. */ - -static bool -conditional_replacement (basic_block cond_bb, basic_block middle_bb, - edge e0, edge e1, tree phi, - tree arg0, tree arg1) -{ - tree result; - tree old_result = NULL; - tree new, cond; - block_stmt_iterator bsi; - edge true_edge, false_edge; - tree new_var = NULL; - tree new_var1; - - /* The PHI arguments have the constants 0 and 1, then convert - it to the conditional. */ - if ((integer_zerop (arg0) && integer_onep (arg1)) - || (integer_zerop (arg1) && integer_onep (arg0))) - ; - else - return false; - - if (!empty_block_p (middle_bb)) - return false; - - /* If the condition is not a naked SSA_NAME and its type does not - match the type of the result, then we have to create a new - variable to optimize this case as it would likely create - non-gimple code when the condition was converted to the - result's type. */ - cond = COND_EXPR_COND (last_stmt (cond_bb)); - result = PHI_RESULT (phi); - if (TREE_CODE (cond) != SSA_NAME - && !lang_hooks.types_compatible_p (TREE_TYPE (cond), TREE_TYPE (result))) - { - tree tmp; - - if (!COMPARISON_CLASS_P (cond)) - return false; - - tmp = create_tmp_var (TREE_TYPE (cond), NULL); - add_referenced_var (tmp); - new_var = make_ssa_name (tmp, NULL); - old_result = cond; - cond = new_var; - } - - /* If the condition was a naked SSA_NAME and the type is not the - same as the type of the result, then convert the type of the - condition. */ - if (!lang_hooks.types_compatible_p (TREE_TYPE (cond), TREE_TYPE (result))) - cond = fold_convert (TREE_TYPE (result), cond); - - /* We need to know which is the true edge and which is the false - edge so that we know when to invert the condition below. */ - extract_true_false_edges_from_block (cond_bb, &true_edge, &false_edge); - - /* Insert our new statement at the end of conditional block before the - COND_EXPR. */ - bsi = bsi_last (cond_bb); - bsi_insert_before (&bsi, build_empty_stmt (), BSI_NEW_STMT); - - if (old_result) - { - tree new1; - - new1 = build2 (TREE_CODE (old_result), TREE_TYPE (old_result), - TREE_OPERAND (old_result, 0), - TREE_OPERAND (old_result, 1)); - - new1 = build2 (MODIFY_EXPR, TREE_TYPE (old_result), new_var, new1); - SSA_NAME_DEF_STMT (new_var) = new1; - - bsi_insert_after (&bsi, new1, BSI_NEW_STMT); - } - - new_var1 = duplicate_ssa_name (PHI_RESULT (phi), NULL); - - - /* At this point we know we have a COND_EXPR with two successors. - One successor is BB, the other successor is an empty block which - falls through into BB. - - There is a single PHI node at the join point (BB) and its arguments - are constants (0, 1). - - So, given the condition COND, and the two PHI arguments, we can - rewrite this PHI into non-branching code: - - dest = (COND) or dest = COND' - - We use the condition as-is if the argument associated with the - true edge has the value one or the argument associated with the - false edge as the value zero. Note that those conditions are not - the same since only one of the outgoing edges from the COND_EXPR - will directly reach BB and thus be associated with an argument. */ - if ((e0 == true_edge && integer_onep (arg0)) - || (e0 == false_edge && integer_zerop (arg0)) - || (e1 == true_edge && integer_onep (arg1)) - || (e1 == false_edge && integer_zerop (arg1))) - { - new = build2 (MODIFY_EXPR, TREE_TYPE (new_var1), new_var1, cond); - } - else - { - tree cond1 = invert_truthvalue (cond); - - cond = cond1; - - /* If what we get back is a conditional expression, there is no - way that it can be gimple. */ - if (TREE_CODE (cond) == COND_EXPR) - { - release_ssa_name (new_var1); - return false; - } - - /* If COND is not something we can expect to be reducible to a GIMPLE - condition, return early. */ - if (is_gimple_cast (cond)) - cond1 = TREE_OPERAND (cond, 0); - if (TREE_CODE (cond1) == TRUTH_NOT_EXPR - && !is_gimple_val (TREE_OPERAND (cond1, 0))) - { - release_ssa_name (new_var1); - return false; - } - - /* If what we get back is not gimple try to create it as gimple by - using a temporary variable. */ - if (is_gimple_cast (cond) - && !is_gimple_val (TREE_OPERAND (cond, 0))) - { - tree op0, tmp, cond_tmp; - - /* Only "real" casts are OK here, not everything that is - acceptable to is_gimple_cast. Make sure we don't do - anything stupid here. */ - gcc_assert (TREE_CODE (cond) == NOP_EXPR - || TREE_CODE (cond) == CONVERT_EXPR); - - op0 = TREE_OPERAND (cond, 0); - tmp = create_tmp_var (TREE_TYPE (op0), NULL); - add_referenced_var (tmp); - cond_tmp = make_ssa_name (tmp, NULL); - new = build2 (MODIFY_EXPR, TREE_TYPE (cond_tmp), cond_tmp, op0); - SSA_NAME_DEF_STMT (cond_tmp) = new; - - bsi_insert_after (&bsi, new, BSI_NEW_STMT); - cond = fold_convert (TREE_TYPE (result), cond_tmp); - } - - new = build2 (MODIFY_EXPR, TREE_TYPE (new_var1), new_var1, cond); - } - - bsi_insert_after (&bsi, new, BSI_NEW_STMT); - - SSA_NAME_DEF_STMT (new_var1) = new; - - replace_phi_edge_with_variable (cond_bb, e1, phi, new_var1); - - /* Note that we optimized this PHI. */ - return true; -} - -/* The function value_replacement does the main work of doing the value - replacement. Return true if the replacement is done. Otherwise return - false. - BB is the basic block where the replacement is going to be done on. ARG0 - is argument 0 from the PHI. Likewise for ARG1. */ - -static bool -value_replacement (basic_block cond_bb, basic_block middle_bb, - edge e0, edge e1, tree phi, - tree arg0, tree arg1) -{ - tree cond; - edge true_edge, false_edge; - - /* If the type says honor signed zeros we cannot do this - optimization. */ - if (HONOR_SIGNED_ZEROS (TYPE_MODE (TREE_TYPE (arg1)))) - return false; - - if (!empty_block_p (middle_bb)) - return false; - - cond = COND_EXPR_COND (last_stmt (cond_bb)); - - /* This transformation is only valid for equality comparisons. */ - if (TREE_CODE (cond) != NE_EXPR && TREE_CODE (cond) != EQ_EXPR) - return false; - - /* We need to know which is the true edge and which is the false - edge so that we know if have abs or negative abs. */ - extract_true_false_edges_from_block (cond_bb, &true_edge, &false_edge); - - /* At this point we know we have a COND_EXPR with two successors. - One successor is BB, the other successor is an empty block which - falls through into BB. - - The condition for the COND_EXPR is known to be NE_EXPR or EQ_EXPR. - - There is a single PHI node at the join point (BB) with two arguments. - - We now need to verify that the two arguments in the PHI node match - the two arguments to the equality comparison. */ - - if ((operand_equal_for_phi_arg_p (arg0, TREE_OPERAND (cond, 0)) - && operand_equal_for_phi_arg_p (arg1, TREE_OPERAND (cond, 1))) - || (operand_equal_for_phi_arg_p (arg1, TREE_OPERAND (cond, 0)) - && operand_equal_for_phi_arg_p (arg0, TREE_OPERAND (cond, 1)))) - { - edge e; - tree arg; - - /* For NE_EXPR, we want to build an assignment result = arg where - arg is the PHI argument associated with the true edge. For - EQ_EXPR we want the PHI argument associated with the false edge. */ - e = (TREE_CODE (cond) == NE_EXPR ? true_edge : false_edge); - - /* Unfortunately, E may not reach BB (it may instead have gone to - OTHER_BLOCK). If that is the case, then we want the single outgoing - edge from OTHER_BLOCK which reaches BB and represents the desired - path from COND_BLOCK. */ - if (e->dest == middle_bb) - e = single_succ_edge (e->dest); - - /* Now we know the incoming edge to BB that has the argument for the - RHS of our new assignment statement. */ - if (e0 == e) - arg = arg0; - else - arg = arg1; - - replace_phi_edge_with_variable (cond_bb, e1, phi, arg); - - /* Note that we optimized this PHI. */ - return true; - } - return false; -} - -/* The function minmax_replacement does the main work of doing the minmax - replacement. Return true if the replacement is done. Otherwise return - false. - BB is the basic block where the replacement is going to be done on. ARG0 - is argument 0 from the PHI. Likewise for ARG1. */ - -static bool -minmax_replacement (basic_block cond_bb, basic_block middle_bb, - edge e0, edge e1, tree phi, - tree arg0, tree arg1) -{ - tree result, type; - tree cond, new; - edge true_edge, false_edge; - enum tree_code cmp, minmax, ass_code; - tree smaller, larger, arg_true, arg_false; - block_stmt_iterator bsi, bsi_from; - - type = TREE_TYPE (PHI_RESULT (phi)); - - /* The optimization may be unsafe due to NaNs. */ - if (HONOR_NANS (TYPE_MODE (type))) - return false; - - cond = COND_EXPR_COND (last_stmt (cond_bb)); - cmp = TREE_CODE (cond); - result = PHI_RESULT (phi); - - /* This transformation is only valid for order comparisons. Record which - operand is smaller/larger if the result of the comparison is true. */ - if (cmp == LT_EXPR || cmp == LE_EXPR) - { - smaller = TREE_OPERAND (cond, 0); - larger = TREE_OPERAND (cond, 1); - } - else if (cmp == GT_EXPR || cmp == GE_EXPR) - { - smaller = TREE_OPERAND (cond, 1); - larger = TREE_OPERAND (cond, 0); - } - else - return false; - - /* We need to know which is the true edge and which is the false - edge so that we know if have abs or negative abs. */ - extract_true_false_edges_from_block (cond_bb, &true_edge, &false_edge); - - /* Forward the edges over the middle basic block. */ - if (true_edge->dest == middle_bb) - true_edge = EDGE_SUCC (true_edge->dest, 0); - if (false_edge->dest == middle_bb) - false_edge = EDGE_SUCC (false_edge->dest, 0); - - if (true_edge == e0) - { - gcc_assert (false_edge == e1); - arg_true = arg0; - arg_false = arg1; - } - else - { - gcc_assert (false_edge == e0); - gcc_assert (true_edge == e1); - arg_true = arg1; - arg_false = arg0; - } - - if (empty_block_p (middle_bb)) - { - if (operand_equal_for_phi_arg_p (arg_true, smaller) - && operand_equal_for_phi_arg_p (arg_false, larger)) - { - /* Case - - if (smaller < larger) - rslt = smaller; - else - rslt = larger; */ - minmax = MIN_EXPR; - } - else if (operand_equal_for_phi_arg_p (arg_false, smaller) - && operand_equal_for_phi_arg_p (arg_true, larger)) - minmax = MAX_EXPR; - else - return false; - } - else - { - /* Recognize the following case, assuming d <= u: - - if (a <= u) - b = MAX (a, d); - x = PHI <b, u> - - This is equivalent to - - b = MAX (a, d); - x = MIN (b, u); */ - - tree assign = last_and_only_stmt (middle_bb); - tree lhs, rhs, op0, op1, bound; - - if (!assign - || TREE_CODE (assign) != MODIFY_EXPR) - return false; - - lhs = TREE_OPERAND (assign, 0); - rhs = TREE_OPERAND (assign, 1); - ass_code = TREE_CODE (rhs); - if (ass_code != MAX_EXPR && ass_code != MIN_EXPR) - return false; - op0 = TREE_OPERAND (rhs, 0); - op1 = TREE_OPERAND (rhs, 1); - - if (true_edge->src == middle_bb) - { - /* We got here if the condition is true, i.e., SMALLER < LARGER. */ - if (!operand_equal_for_phi_arg_p (lhs, arg_true)) - return false; - - if (operand_equal_for_phi_arg_p (arg_false, larger)) - { - /* Case - - if (smaller < larger) - { - r' = MAX_EXPR (smaller, bound) - } - r = PHI <r', larger> --> to be turned to MIN_EXPR. */ - if (ass_code != MAX_EXPR) - return false; - - minmax = MIN_EXPR; - if (operand_equal_for_phi_arg_p (op0, smaller)) - bound = op1; - else if (operand_equal_for_phi_arg_p (op1, smaller)) - bound = op0; - else - return false; - - /* We need BOUND <= LARGER. */ - if (!integer_nonzerop (fold_build2 (LE_EXPR, boolean_type_node, - bound, larger))) - return false; - } - else if (operand_equal_for_phi_arg_p (arg_false, smaller)) - { - /* Case - - if (smaller < larger) - { - r' = MIN_EXPR (larger, bound) - } - r = PHI <r', smaller> --> to be turned to MAX_EXPR. */ - if (ass_code != MIN_EXPR) - return false; - - minmax = MAX_EXPR; - if (operand_equal_for_phi_arg_p (op0, larger)) - bound = op1; - else if (operand_equal_for_phi_arg_p (op1, larger)) - bound = op0; - else - return false; - - /* We need BOUND >= SMALLER. */ - if (!integer_nonzerop (fold_build2 (GE_EXPR, boolean_type_node, - bound, smaller))) - return false; - } - else - return false; - } - else - { - /* We got here if the condition is false, i.e., SMALLER > LARGER. */ - if (!operand_equal_for_phi_arg_p (lhs, arg_false)) - return false; - - if (operand_equal_for_phi_arg_p (arg_true, larger)) - { - /* Case - - if (smaller > larger) - { - r' = MIN_EXPR (smaller, bound) - } - r = PHI <r', larger> --> to be turned to MAX_EXPR. */ - if (ass_code != MIN_EXPR) - return false; - - minmax = MAX_EXPR; - if (operand_equal_for_phi_arg_p (op0, smaller)) - bound = op1; - else if (operand_equal_for_phi_arg_p (op1, smaller)) - bound = op0; - else - return false; - - /* We need BOUND >= LARGER. */ - if (!integer_nonzerop (fold_build2 (GE_EXPR, boolean_type_node, - bound, larger))) - return false; - } - else if (operand_equal_for_phi_arg_p (arg_true, smaller)) - { - /* Case - - if (smaller > larger) - { - r' = MAX_EXPR (larger, bound) - } - r = PHI <r', smaller> --> to be turned to MIN_EXPR. */ - if (ass_code != MAX_EXPR) - return false; - - minmax = MIN_EXPR; - if (operand_equal_for_phi_arg_p (op0, larger)) - bound = op1; - else if (operand_equal_for_phi_arg_p (op1, larger)) - bound = op0; - else - return false; - - /* We need BOUND <= SMALLER. */ - if (!integer_nonzerop (fold_build2 (LE_EXPR, boolean_type_node, - bound, smaller))) - return false; - } - else - return false; - } - - /* Move the statement from the middle block. */ - bsi = bsi_last (cond_bb); - bsi_from = bsi_last (middle_bb); - bsi_move_before (&bsi_from, &bsi); - } - - /* Emit the statement to compute min/max. */ - result = duplicate_ssa_name (PHI_RESULT (phi), NULL); - new = build2 (MODIFY_EXPR, type, result, - build2 (minmax, type, arg0, arg1)); - SSA_NAME_DEF_STMT (result) = new; - bsi = bsi_last (cond_bb); - bsi_insert_before (&bsi, new, BSI_NEW_STMT); - - replace_phi_edge_with_variable (cond_bb, e1, phi, result); - return true; -} - -/* The function absolute_replacement does the main work of doing the absolute - replacement. Return true if the replacement is done. Otherwise return - false. - bb is the basic block where the replacement is going to be done on. arg0 - is argument 0 from the phi. Likewise for arg1. */ - -static bool -abs_replacement (basic_block cond_bb, basic_block middle_bb, - edge e0 ATTRIBUTE_UNUSED, edge e1, - tree phi, tree arg0, tree arg1) -{ - tree result; - tree new, cond; - block_stmt_iterator bsi; - edge true_edge, false_edge; - tree assign; - edge e; - tree rhs, lhs; - bool negate; - enum tree_code cond_code; - - /* If the type says honor signed zeros we cannot do this - optimization. */ - if (HONOR_SIGNED_ZEROS (TYPE_MODE (TREE_TYPE (arg1)))) - return false; - - /* OTHER_BLOCK must have only one executable statement which must have the - form arg0 = -arg1 or arg1 = -arg0. */ - - assign = last_and_only_stmt (middle_bb); - /* If we did not find the proper negation assignment, then we can not - optimize. */ - if (assign == NULL) - return false; - - /* If we got here, then we have found the only executable statement - in OTHER_BLOCK. If it is anything other than arg = -arg1 or - arg1 = -arg0, then we can not optimize. */ - if (TREE_CODE (assign) != MODIFY_EXPR) - return false; - - lhs = TREE_OPERAND (assign, 0); - rhs = TREE_OPERAND (assign, 1); - - if (TREE_CODE (rhs) != NEGATE_EXPR) - return false; - - rhs = TREE_OPERAND (rhs, 0); - - /* The assignment has to be arg0 = -arg1 or arg1 = -arg0. */ - if (!(lhs == arg0 && rhs == arg1) - && !(lhs == arg1 && rhs == arg0)) - return false; - - cond = COND_EXPR_COND (last_stmt (cond_bb)); - result = PHI_RESULT (phi); - - /* Only relationals comparing arg[01] against zero are interesting. */ - cond_code = TREE_CODE (cond); - if (cond_code != GT_EXPR && cond_code != GE_EXPR - && cond_code != LT_EXPR && cond_code != LE_EXPR) - return false; - - /* Make sure the conditional is arg[01] OP y. */ - if (TREE_OPERAND (cond, 0) != rhs) - return false; - - if (FLOAT_TYPE_P (TREE_TYPE (TREE_OPERAND (cond, 1))) - ? real_zerop (TREE_OPERAND (cond, 1)) - : integer_zerop (TREE_OPERAND (cond, 1))) - ; - else - return false; - - /* We need to know which is the true edge and which is the false - edge so that we know if have abs or negative abs. */ - extract_true_false_edges_from_block (cond_bb, &true_edge, &false_edge); - - /* For GT_EXPR/GE_EXPR, if the true edge goes to OTHER_BLOCK, then we - will need to negate the result. Similarly for LT_EXPR/LE_EXPR if - the false edge goes to OTHER_BLOCK. */ - if (cond_code == GT_EXPR || cond_code == GE_EXPR) - e = true_edge; - else - e = false_edge; - - if (e->dest == middle_bb) - negate = true; - else - negate = false; - - result = duplicate_ssa_name (result, NULL); - - if (negate) - { - tree tmp = create_tmp_var (TREE_TYPE (result), NULL); - add_referenced_var (tmp); - lhs = make_ssa_name (tmp, NULL); - } - else - lhs = result; - - /* Build the modify expression with abs expression. */ - new = build2 (MODIFY_EXPR, TREE_TYPE (lhs), - lhs, build1 (ABS_EXPR, TREE_TYPE (lhs), rhs)); - SSA_NAME_DEF_STMT (lhs) = new; - - bsi = bsi_last (cond_bb); - bsi_insert_before (&bsi, new, BSI_NEW_STMT); - - if (negate) - { - /* Get the right BSI. We want to insert after the recently - added ABS_EXPR statement (which we know is the first statement - in the block. */ - new = build2 (MODIFY_EXPR, TREE_TYPE (result), - result, build1 (NEGATE_EXPR, TREE_TYPE (lhs), lhs)); - SSA_NAME_DEF_STMT (result) = new; - - bsi_insert_after (&bsi, new, BSI_NEW_STMT); - } - - replace_phi_edge_with_variable (cond_bb, e1, phi, result); - - /* Note that we optimized this PHI. */ - return true; -} - - -/* Always do these optimizations if we have SSA - trees to work on. */ -static bool -gate_phiopt (void) -{ - return 1; -} - -struct tree_opt_pass pass_phiopt = -{ - "phiopt", /* name */ - gate_phiopt, /* gate */ - tree_ssa_phiopt, /* execute */ - NULL, /* sub */ - NULL, /* next */ - 0, /* static_pass_number */ - TV_TREE_PHIOPT, /* tv_id */ - PROP_cfg | PROP_ssa | PROP_alias, /* properties_required */ - 0, /* properties_provided */ - 0, /* properties_destroyed */ - 0, /* todo_flags_start */ - TODO_dump_func - | TODO_ggc_collect - | TODO_verify_ssa - | TODO_verify_flow - | TODO_verify_stmts, /* todo_flags_finish */ - 0 /* letter */ -}; |