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Diffstat (limited to 'gcc-4.8.1/gcc/tree-ssa-phiprop.c')
| -rw-r--r-- | gcc-4.8.1/gcc/tree-ssa-phiprop.c | 427 |
1 files changed, 0 insertions, 427 deletions
diff --git a/gcc-4.8.1/gcc/tree-ssa-phiprop.c b/gcc-4.8.1/gcc/tree-ssa-phiprop.c deleted file mode 100644 index 4da181487..000000000 --- a/gcc-4.8.1/gcc/tree-ssa-phiprop.c +++ /dev/null @@ -1,427 +0,0 @@ -/* Backward propagation of indirect loads through PHIs. - Copyright (C) 2007-2013 Free Software Foundation, Inc. - Contributed by Richard Guenther <rguenther@suse.de> - -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 3, 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 COPYING3. If not see -<http://www.gnu.org/licenses/>. */ - -#include "config.h" -#include "system.h" -#include "coretypes.h" -#include "tm.h" -#include "tree.h" -#include "tm_p.h" -#include "basic-block.h" -#include "gimple-pretty-print.h" -#include "tree-flow.h" -#include "tree-pass.h" -#include "langhooks.h" -#include "flags.h" - -/* This pass propagates indirect loads through the PHI node for its - address to make the load source possibly non-addressable and to - allow for PHI optimization to trigger. - - For example the pass changes - - # addr_1 = PHI <&a, &b> - tmp_1 = *addr_1; - - to - - # tmp_1 = PHI <a, b> - - but also handles more complex scenarios like - - D.2077_2 = &this_1(D)->a1; - ... - - # b_12 = PHI <&c(2), D.2077_2(3)> - D.2114_13 = *b_12; - ... - - # b_15 = PHI <b_12(4), &b(5)> - D.2080_5 = &this_1(D)->a0; - ... - - # b_18 = PHI <D.2080_5(6), &c(7)> - ... - - # b_21 = PHI <b_15(8), b_18(9)> - D.2076_8 = *b_21; - - where the addresses loaded are defined by PHIs itself. - The above happens for - - std::max(std::min(a0, c), std::min(std::max(a1, c), b)) - - where this pass transforms it to a form later PHI optimization - recognizes and transforms it to the simple - - D.2109_10 = this_1(D)->a1; - D.2110_11 = c; - D.2114_31 = MAX_EXPR <D.2109_10, D.2110_11>; - D.2115_14 = b; - D.2125_17 = MIN_EXPR <D.2115_14, D.2114_31>; - D.2119_16 = this_1(D)->a0; - D.2124_32 = MIN_EXPR <D.2110_11, D.2119_16>; - D.2076_33 = MAX_EXPR <D.2125_17, D.2124_32>; - - The pass does a dominator walk processing loads using a basic-block - local analysis and stores the result for use by transformations on - dominated basic-blocks. */ - - -/* Structure to keep track of the value of a dereferenced PHI result - and the virtual operand used for that dereference. */ - -struct phiprop_d -{ - tree value; - tree vuse; -}; - -/* Verify if the value recorded for NAME in PHIVN is still valid at - the start of basic block BB. */ - -static bool -phivn_valid_p (struct phiprop_d *phivn, tree name, basic_block bb) -{ - tree vuse = phivn[SSA_NAME_VERSION (name)].vuse; - gimple use_stmt; - imm_use_iterator ui2; - bool ok = true; - - /* The def stmts of the virtual uses need to be dominated by bb. */ - gcc_assert (vuse != NULL_TREE); - - FOR_EACH_IMM_USE_STMT (use_stmt, ui2, vuse) - { - /* If BB does not dominate a VDEF, the value is invalid. */ - if ((gimple_vdef (use_stmt) != NULL_TREE - || gimple_code (use_stmt) == GIMPLE_PHI) - && !dominated_by_p (CDI_DOMINATORS, gimple_bb (use_stmt), bb)) - { - ok = false; - BREAK_FROM_IMM_USE_STMT (ui2); - } - } - - return ok; -} - -/* Insert a new phi node for the dereference of PHI at basic_block - BB with the virtual operands from USE_STMT. */ - -static tree -phiprop_insert_phi (basic_block bb, gimple phi, gimple use_stmt, - struct phiprop_d *phivn, size_t n) -{ - tree res; - gimple new_phi; - edge_iterator ei; - edge e; - - gcc_assert (is_gimple_assign (use_stmt) - && gimple_assign_rhs_code (use_stmt) == MEM_REF); - - /* Build a new PHI node to replace the definition of - the indirect reference lhs. */ - res = gimple_assign_lhs (use_stmt); - new_phi = create_phi_node (res, bb); - - if (dump_file && (dump_flags & TDF_DETAILS)) - { - fprintf (dump_file, "Inserting PHI for result of load "); - print_gimple_stmt (dump_file, use_stmt, 0, 0); - } - - /* Add PHI arguments for each edge inserting loads of the - addressable operands. */ - FOR_EACH_EDGE (e, ei, bb->preds) - { - tree old_arg, new_var; - gimple tmp; - source_location locus; - - old_arg = PHI_ARG_DEF_FROM_EDGE (phi, e); - locus = gimple_phi_arg_location_from_edge (phi, e); - while (TREE_CODE (old_arg) == SSA_NAME - && (SSA_NAME_VERSION (old_arg) >= n - || phivn[SSA_NAME_VERSION (old_arg)].value == NULL_TREE)) - { - gimple def_stmt = SSA_NAME_DEF_STMT (old_arg); - old_arg = gimple_assign_rhs1 (def_stmt); - locus = gimple_location (def_stmt); - } - - if (TREE_CODE (old_arg) == SSA_NAME) - { - if (dump_file && (dump_flags & TDF_DETAILS)) - { - fprintf (dump_file, " for edge defining "); - print_generic_expr (dump_file, PHI_ARG_DEF_FROM_EDGE (phi, e), 0); - fprintf (dump_file, " reusing PHI result "); - print_generic_expr (dump_file, - phivn[SSA_NAME_VERSION (old_arg)].value, 0); - fprintf (dump_file, "\n"); - } - /* Reuse a formerly created dereference. */ - new_var = phivn[SSA_NAME_VERSION (old_arg)].value; - } - else - { - tree rhs = gimple_assign_rhs1 (use_stmt); - gcc_assert (TREE_CODE (old_arg) == ADDR_EXPR); - new_var = make_ssa_name (TREE_TYPE (rhs), NULL); - if (!is_gimple_min_invariant (old_arg)) - old_arg = PHI_ARG_DEF_FROM_EDGE (phi, e); - else - old_arg = unshare_expr (old_arg); - tmp = gimple_build_assign (new_var, - fold_build2 (MEM_REF, TREE_TYPE (rhs), - old_arg, - TREE_OPERAND (rhs, 1))); - gimple_set_location (tmp, locus); - - gsi_insert_on_edge (e, tmp); - update_stmt (tmp); - - if (dump_file && (dump_flags & TDF_DETAILS)) - { - fprintf (dump_file, " for edge defining "); - print_generic_expr (dump_file, PHI_ARG_DEF_FROM_EDGE (phi, e), 0); - fprintf (dump_file, " inserting load "); - print_gimple_stmt (dump_file, tmp, 0, 0); - } - } - - add_phi_arg (new_phi, new_var, e, locus); - } - - update_stmt (new_phi); - - if (dump_file && (dump_flags & TDF_DETAILS)) - print_gimple_stmt (dump_file, new_phi, 0, 0); - - return res; -} - -/* Propagate between the phi node arguments of PHI in BB and phi result - users. For now this matches - # p_2 = PHI <&x, &y> - <Lx>:; - p_3 = p_2; - z_2 = *p_3; - and converts it to - # z_2 = PHI <x, y> - <Lx>:; - Returns true if a transformation was done and edge insertions - need to be committed. Global data PHIVN and N is used to track - past transformation results. We need to be especially careful here - with aliasing issues as we are moving memory reads. */ - -static bool -propagate_with_phi (basic_block bb, gimple phi, struct phiprop_d *phivn, - size_t n) -{ - tree ptr = PHI_RESULT (phi); - gimple use_stmt; - tree res = NULL_TREE; - gimple_stmt_iterator gsi; - imm_use_iterator ui; - use_operand_p arg_p, use; - ssa_op_iter i; - bool phi_inserted; - tree type = NULL_TREE; - bool one_invariant = false; - - if (!POINTER_TYPE_P (TREE_TYPE (ptr)) - || !is_gimple_reg_type (TREE_TYPE (TREE_TYPE (ptr)))) - return false; - - /* Check if we can "cheaply" dereference all phi arguments. */ - FOR_EACH_PHI_ARG (arg_p, phi, i, SSA_OP_USE) - { - tree arg = USE_FROM_PTR (arg_p); - /* Walk the ssa chain until we reach a ssa name we already - created a value for or we reach a definition of the form - ssa_name_n = &var; */ - while (TREE_CODE (arg) == SSA_NAME - && !SSA_NAME_IS_DEFAULT_DEF (arg) - && (SSA_NAME_VERSION (arg) >= n - || phivn[SSA_NAME_VERSION (arg)].value == NULL_TREE)) - { - gimple def_stmt = SSA_NAME_DEF_STMT (arg); - if (!gimple_assign_single_p (def_stmt)) - return false; - arg = gimple_assign_rhs1 (def_stmt); - } - if (TREE_CODE (arg) != ADDR_EXPR - && !(TREE_CODE (arg) == SSA_NAME - && SSA_NAME_VERSION (arg) < n - && phivn[SSA_NAME_VERSION (arg)].value != NULL_TREE - && (!type - || types_compatible_p - (type, TREE_TYPE (phivn[SSA_NAME_VERSION (arg)].value))) - && phivn_valid_p (phivn, arg, bb))) - return false; - if (!type - && TREE_CODE (arg) == SSA_NAME) - type = TREE_TYPE (phivn[SSA_NAME_VERSION (arg)].value); - if (TREE_CODE (arg) == ADDR_EXPR - && is_gimple_min_invariant (arg)) - one_invariant = true; - } - - /* If we neither have an address of a decl nor can reuse a previously - inserted load, do not hoist anything. */ - if (!one_invariant - && !type) - return false; - - /* Find a dereferencing use. First follow (single use) ssa - copy chains for ptr. */ - while (single_imm_use (ptr, &use, &use_stmt) - && gimple_assign_ssa_name_copy_p (use_stmt)) - ptr = gimple_assign_lhs (use_stmt); - - /* Replace the first dereference of *ptr if there is one and if we - can move the loads to the place of the ptr phi node. */ - phi_inserted = false; - FOR_EACH_IMM_USE_STMT (use_stmt, ui, ptr) - { - gimple def_stmt; - tree vuse; - - /* Check whether this is a load of *ptr. */ - if (!(is_gimple_assign (use_stmt) - && TREE_CODE (gimple_assign_lhs (use_stmt)) == SSA_NAME - && gimple_assign_rhs_code (use_stmt) == MEM_REF - && TREE_OPERAND (gimple_assign_rhs1 (use_stmt), 0) == ptr - && integer_zerop (TREE_OPERAND (gimple_assign_rhs1 (use_stmt), 1)) - && (!type - || types_compatible_p - (TREE_TYPE (gimple_assign_lhs (use_stmt)), type)) - /* We cannot replace a load that may throw or is volatile. */ - && !stmt_can_throw_internal (use_stmt))) - continue; - - /* Check if we can move the loads. The def stmt of the virtual use - needs to be in a different basic block dominating bb. */ - vuse = gimple_vuse (use_stmt); - def_stmt = SSA_NAME_DEF_STMT (vuse); - if (!SSA_NAME_IS_DEFAULT_DEF (vuse) - && (gimple_bb (def_stmt) == bb - || !dominated_by_p (CDI_DOMINATORS, - bb, gimple_bb (def_stmt)))) - goto next; - - /* Found a proper dereference. Insert a phi node if this - is the first load transformation. */ - if (!phi_inserted) - { - res = phiprop_insert_phi (bb, phi, use_stmt, phivn, n); - type = TREE_TYPE (res); - - /* Remember the value we created for *ptr. */ - phivn[SSA_NAME_VERSION (ptr)].value = res; - phivn[SSA_NAME_VERSION (ptr)].vuse = vuse; - - /* Remove old stmt. The phi is taken care of by DCE, if we - want to delete it here we also have to delete all intermediate - copies. */ - gsi = gsi_for_stmt (use_stmt); - gsi_remove (&gsi, true); - - phi_inserted = true; - } - else - { - /* Further replacements are easy, just make a copy out of the - load. */ - gimple_assign_set_rhs1 (use_stmt, res); - update_stmt (use_stmt); - } - -next:; - /* Continue searching for a proper dereference. */ - } - - return phi_inserted; -} - -/* Main entry for phiprop pass. */ - -static unsigned int -tree_ssa_phiprop (void) -{ - vec<basic_block> bbs; - struct phiprop_d *phivn; - bool did_something = false; - basic_block bb; - gimple_stmt_iterator gsi; - unsigned i; - size_t n; - - calculate_dominance_info (CDI_DOMINATORS); - - n = num_ssa_names; - phivn = XCNEWVEC (struct phiprop_d, n); - - /* Walk the dominator tree in preorder. */ - bbs = get_all_dominated_blocks (CDI_DOMINATORS, - single_succ (ENTRY_BLOCK_PTR)); - FOR_EACH_VEC_ELT (bbs, i, bb) - for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi)) - did_something |= propagate_with_phi (bb, gsi_stmt (gsi), phivn, n); - - if (did_something) - gsi_commit_edge_inserts (); - - bbs.release (); - free (phivn); - - return 0; -} - -static bool -gate_phiprop (void) -{ - return flag_tree_phiprop; -} - -struct gimple_opt_pass pass_phiprop = -{ - { - GIMPLE_PASS, - "phiprop", /* name */ - OPTGROUP_NONE, /* optinfo_flags */ - gate_phiprop, /* gate */ - tree_ssa_phiprop, /* execute */ - NULL, /* sub */ - NULL, /* next */ - 0, /* static_pass_number */ - TV_TREE_PHIPROP, /* tv_id */ - PROP_cfg | PROP_ssa, /* properties_required */ - 0, /* properties_provided */ - 0, /* properties_destroyed */ - 0, /* todo_flags_start */ - TODO_ggc_collect - | TODO_update_ssa - | TODO_verify_ssa /* todo_flags_finish */ - } -}; |