| /* Loop invariant motion. |
| Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008 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 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 "rtl.h" |
| #include "tm_p.h" |
| #include "hard-reg-set.h" |
| #include "basic-block.h" |
| #include "output.h" |
| #include "diagnostic.h" |
| #include "tree-flow.h" |
| #include "tree-dump.h" |
| #include "timevar.h" |
| #include "cfgloop.h" |
| #include "domwalk.h" |
| #include "params.h" |
| #include "tree-pass.h" |
| #include "flags.h" |
| #include "real.h" |
| #include "hashtab.h" |
| #include "tree-affine.h" |
| #include "pointer-set.h" |
| #include "tree-ssa-propagate.h" |
| |
| /* TODO: Support for predicated code motion. I.e. |
| |
| while (1) |
| { |
| if (cond) |
| { |
| a = inv; |
| something; |
| } |
| } |
| |
| Where COND and INV are is invariants, but evaluating INV may trap or be |
| invalid from some other reason if !COND. This may be transformed to |
| |
| if (cond) |
| a = inv; |
| while (1) |
| { |
| if (cond) |
| something; |
| } */ |
| |
| /* A type for the list of statements that have to be moved in order to be able |
| to hoist an invariant computation. */ |
| |
| struct depend |
| { |
| gimple stmt; |
| struct depend *next; |
| }; |
| |
| /* The auxiliary data kept for each statement. */ |
| |
| struct lim_aux_data |
| { |
| struct loop *max_loop; /* The outermost loop in that the statement |
| is invariant. */ |
| |
| struct loop *tgt_loop; /* The loop out of that we want to move the |
| invariant. */ |
| |
| struct loop *always_executed_in; |
| /* The outermost loop for that we are sure |
| the statement is executed if the loop |
| is entered. */ |
| |
| unsigned cost; /* Cost of the computation performed by the |
| statement. */ |
| |
| struct depend *depends; /* List of statements that must be also hoisted |
| out of the loop when this statement is |
| hoisted; i.e. those that define the operands |
| of the statement and are inside of the |
| MAX_LOOP loop. */ |
| }; |
| |
| /* Maps statements to their lim_aux_data. */ |
| |
| static struct pointer_map_t *lim_aux_data_map; |
| |
| /* Description of a memory reference location. */ |
| |
| typedef struct mem_ref_loc |
| { |
| tree *ref; /* The reference itself. */ |
| gimple stmt; /* The statement in that it occurs. */ |
| } *mem_ref_loc_p; |
| |
| DEF_VEC_P(mem_ref_loc_p); |
| DEF_VEC_ALLOC_P(mem_ref_loc_p, heap); |
| |
| /* The list of memory reference locations in a loop. */ |
| |
| typedef struct mem_ref_locs |
| { |
| VEC (mem_ref_loc_p, heap) *locs; |
| } *mem_ref_locs_p; |
| |
| DEF_VEC_P(mem_ref_locs_p); |
| DEF_VEC_ALLOC_P(mem_ref_locs_p, heap); |
| |
| /* Description of a memory reference. */ |
| |
| typedef struct mem_ref |
| { |
| tree mem; /* The memory itself. */ |
| unsigned id; /* ID assigned to the memory reference |
| (its index in memory_accesses.refs_list) */ |
| hashval_t hash; /* Its hash value. */ |
| bitmap stored; /* The set of loops in that this memory location |
| is stored to. */ |
| VEC (mem_ref_locs_p, heap) *accesses_in_loop; |
| /* The locations of the accesses. Vector |
| indexed by the loop number. */ |
| bitmap vops; /* Vops corresponding to this memory |
| location. */ |
| |
| /* The following sets are computed on demand. We keep both set and |
| its complement, so that we know whether the information was |
| already computed or not. */ |
| bitmap indep_loop; /* The set of loops in that the memory |
| reference is independent, meaning: |
| If it is stored in the loop, this store |
| is independent on all other loads and |
| stores. |
| If it is only loaded, then it is independent |
| on all stores in the loop. */ |
| bitmap dep_loop; /* The complement of INDEP_LOOP. */ |
| |
| bitmap indep_ref; /* The set of memory references on that |
| this reference is independent. */ |
| bitmap dep_ref; /* The complement of DEP_REF. */ |
| } *mem_ref_p; |
| |
| DEF_VEC_P(mem_ref_p); |
| DEF_VEC_ALLOC_P(mem_ref_p, heap); |
| |
| DEF_VEC_P(bitmap); |
| DEF_VEC_ALLOC_P(bitmap, heap); |
| |
| DEF_VEC_P(htab_t); |
| DEF_VEC_ALLOC_P(htab_t, heap); |
| |
| /* Description of memory accesses in loops. */ |
| |
| static struct |
| { |
| /* The hash table of memory references accessed in loops. */ |
| htab_t refs; |
| |
| /* The list of memory references. */ |
| VEC (mem_ref_p, heap) *refs_list; |
| |
| /* The set of memory references accessed in each loop. */ |
| VEC (bitmap, heap) *refs_in_loop; |
| |
| /* The set of memory references accessed in each loop, including |
| subloops. */ |
| VEC (bitmap, heap) *all_refs_in_loop; |
| |
| /* The set of virtual operands clobbered in a given loop. */ |
| VEC (bitmap, heap) *clobbered_vops; |
| |
| /* Map from the pair (loop, virtual operand) to the set of refs that |
| touch the virtual operand in the loop. */ |
| VEC (htab_t, heap) *vop_ref_map; |
| |
| /* Cache for expanding memory addresses. */ |
| struct pointer_map_t *ttae_cache; |
| } memory_accesses; |
| |
| static bool ref_indep_loop_p (struct loop *, mem_ref_p); |
| |
| /* Minimum cost of an expensive expression. */ |
| #define LIM_EXPENSIVE ((unsigned) PARAM_VALUE (PARAM_LIM_EXPENSIVE)) |
| |
| /* The outermost loop for that execution of the header guarantees that the |
| block will be executed. */ |
| #define ALWAYS_EXECUTED_IN(BB) ((struct loop *) (BB)->aux) |
| |
| static struct lim_aux_data * |
| init_lim_data (gimple stmt) |
| { |
| void **p = pointer_map_insert (lim_aux_data_map, stmt); |
| |
| *p = XCNEW (struct lim_aux_data); |
| return (struct lim_aux_data *) *p; |
| } |
| |
| static struct lim_aux_data * |
| get_lim_data (gimple stmt) |
| { |
| void **p = pointer_map_contains (lim_aux_data_map, stmt); |
| if (!p) |
| return NULL; |
| |
| return (struct lim_aux_data *) *p; |
| } |
| |
| /* Releases the memory occupied by DATA. */ |
| |
| static void |
| free_lim_aux_data (struct lim_aux_data *data) |
| { |
| struct depend *dep, *next; |
| |
| for (dep = data->depends; dep; dep = next) |
| { |
| next = dep->next; |
| free (dep); |
| } |
| free (data); |
| } |
| |
| static void |
| clear_lim_data (gimple stmt) |
| { |
| void **p = pointer_map_contains (lim_aux_data_map, stmt); |
| if (!p) |
| return; |
| |
| free_lim_aux_data ((struct lim_aux_data *) *p); |
| *p = NULL; |
| } |
| |
| /* Calls CBCK for each index in memory reference ADDR_P. There are two |
| kinds situations handled; in each of these cases, the memory reference |
| and DATA are passed to the callback: |
| |
| Access to an array: ARRAY_{RANGE_}REF (base, index). In this case we also |
| pass the pointer to the index to the callback. |
| |
| Pointer dereference: INDIRECT_REF (addr). In this case we also pass the |
| pointer to addr to the callback. |
| |
| If the callback returns false, the whole search stops and false is returned. |
| Otherwise the function returns true after traversing through the whole |
| reference *ADDR_P. */ |
| |
| bool |
| for_each_index (tree *addr_p, bool (*cbck) (tree, tree *, void *), void *data) |
| { |
| tree *nxt, *idx; |
| |
| for (; ; addr_p = nxt) |
| { |
| switch (TREE_CODE (*addr_p)) |
| { |
| case SSA_NAME: |
| return cbck (*addr_p, addr_p, data); |
| |
| case MISALIGNED_INDIRECT_REF: |
| case ALIGN_INDIRECT_REF: |
| case INDIRECT_REF: |
| nxt = &TREE_OPERAND (*addr_p, 0); |
| return cbck (*addr_p, nxt, data); |
| |
| case BIT_FIELD_REF: |
| case VIEW_CONVERT_EXPR: |
| case REALPART_EXPR: |
| case IMAGPART_EXPR: |
| nxt = &TREE_OPERAND (*addr_p, 0); |
| break; |
| |
| case COMPONENT_REF: |
| /* If the component has varying offset, it behaves like index |
| as well. */ |
| idx = &TREE_OPERAND (*addr_p, 2); |
| if (*idx |
| && !cbck (*addr_p, idx, data)) |
| return false; |
| |
| nxt = &TREE_OPERAND (*addr_p, 0); |
| break; |
| |
| case ARRAY_REF: |
| case ARRAY_RANGE_REF: |
| nxt = &TREE_OPERAND (*addr_p, 0); |
| if (!cbck (*addr_p, &TREE_OPERAND (*addr_p, 1), data)) |
| return false; |
| break; |
| |
| case VAR_DECL: |
| case PARM_DECL: |
| case STRING_CST: |
| case RESULT_DECL: |
| case VECTOR_CST: |
| case COMPLEX_CST: |
| case INTEGER_CST: |
| case REAL_CST: |
| case FIXED_CST: |
| case CONSTRUCTOR: |
| return true; |
| |
| case ADDR_EXPR: |
| gcc_assert (is_gimple_min_invariant (*addr_p)); |
| return true; |
| |
| case TARGET_MEM_REF: |
| idx = &TMR_BASE (*addr_p); |
| if (*idx |
| && !cbck (*addr_p, idx, data)) |
| return false; |
| idx = &TMR_INDEX (*addr_p); |
| if (*idx |
| && !cbck (*addr_p, idx, data)) |
| return false; |
| return true; |
| |
| default: |
| gcc_unreachable (); |
| } |
| } |
| } |
| |
| /* If it is possible to hoist the statement STMT unconditionally, |
| returns MOVE_POSSIBLE. |
| If it is possible to hoist the statement STMT, but we must avoid making |
| it executed if it would not be executed in the original program (e.g. |
| because it may trap), return MOVE_PRESERVE_EXECUTION. |
| Otherwise return MOVE_IMPOSSIBLE. */ |
| |
| enum move_pos |
| movement_possibility (gimple stmt) |
| { |
| tree lhs; |
| enum move_pos ret = MOVE_POSSIBLE; |
| |
| if (flag_unswitch_loops |
| && gimple_code (stmt) == GIMPLE_COND) |
| { |
| /* If we perform unswitching, force the operands of the invariant |
| condition to be moved out of the loop. */ |
| return MOVE_POSSIBLE; |
| } |
| |
| if (gimple_get_lhs (stmt) == NULL_TREE) |
| return MOVE_IMPOSSIBLE; |
| |
| if (!ZERO_SSA_OPERANDS (stmt, SSA_OP_VIRTUAL_DEFS)) |
| return MOVE_IMPOSSIBLE; |
| |
| if (stmt_ends_bb_p (stmt) |
| || gimple_has_volatile_ops (stmt) |
| || gimple_has_side_effects (stmt) |
| || stmt_could_throw_p (stmt)) |
| return MOVE_IMPOSSIBLE; |
| |
| if (is_gimple_call (stmt)) |
| { |
| /* While pure or const call is guaranteed to have no side effects, we |
| cannot move it arbitrarily. Consider code like |
| |
| char *s = something (); |
| |
| while (1) |
| { |
| if (s) |
| t = strlen (s); |
| else |
| t = 0; |
| } |
| |
| Here the strlen call cannot be moved out of the loop, even though |
| s is invariant. In addition to possibly creating a call with |
| invalid arguments, moving out a function call that is not executed |
| may cause performance regressions in case the call is costly and |
| not executed at all. */ |
| ret = MOVE_PRESERVE_EXECUTION; |
| lhs = gimple_call_lhs (stmt); |
| } |
| else if (is_gimple_assign (stmt)) |
| lhs = gimple_assign_lhs (stmt); |
| else |
| return MOVE_IMPOSSIBLE; |
| |
| if (TREE_CODE (lhs) == SSA_NAME |
| && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (lhs)) |
| return MOVE_IMPOSSIBLE; |
| |
| if (TREE_CODE (lhs) != SSA_NAME |
| || gimple_could_trap_p (stmt)) |
| return MOVE_PRESERVE_EXECUTION; |
| |
| return ret; |
| } |
| |
| /* Suppose that operand DEF is used inside the LOOP. Returns the outermost |
| loop to that we could move the expression using DEF if it did not have |
| other operands, i.e. the outermost loop enclosing LOOP in that the value |
| of DEF is invariant. */ |
| |
| static struct loop * |
| outermost_invariant_loop (tree def, struct loop *loop) |
| { |
| gimple def_stmt; |
| basic_block def_bb; |
| struct loop *max_loop; |
| struct lim_aux_data *lim_data; |
| |
| if (!def) |
| return superloop_at_depth (loop, 1); |
| |
| if (TREE_CODE (def) != SSA_NAME) |
| { |
| gcc_assert (is_gimple_min_invariant (def)); |
| return superloop_at_depth (loop, 1); |
| } |
| |
| def_stmt = SSA_NAME_DEF_STMT (def); |
| def_bb = gimple_bb (def_stmt); |
| if (!def_bb) |
| return superloop_at_depth (loop, 1); |
| |
| max_loop = find_common_loop (loop, def_bb->loop_father); |
| |
| lim_data = get_lim_data (def_stmt); |
| if (lim_data != NULL && lim_data->max_loop != NULL) |
| max_loop = find_common_loop (max_loop, |
| loop_outer (lim_data->max_loop)); |
| if (max_loop == loop) |
| return NULL; |
| max_loop = superloop_at_depth (loop, loop_depth (max_loop) + 1); |
| |
| return max_loop; |
| } |
| |
| /* DATA is a structure containing information associated with a statement |
| inside LOOP. DEF is one of the operands of this statement. |
| |
| Find the outermost loop enclosing LOOP in that value of DEF is invariant |
| and record this in DATA->max_loop field. If DEF itself is defined inside |
| this loop as well (i.e. we need to hoist it out of the loop if we want |
| to hoist the statement represented by DATA), record the statement in that |
| DEF is defined to the DATA->depends list. Additionally if ADD_COST is true, |
| add the cost of the computation of DEF to the DATA->cost. |
| |
| If DEF is not invariant in LOOP, return false. Otherwise return TRUE. */ |
| |
| static bool |
| add_dependency (tree def, struct lim_aux_data *data, struct loop *loop, |
| bool add_cost) |
| { |
| gimple def_stmt = SSA_NAME_DEF_STMT (def); |
| basic_block def_bb = gimple_bb (def_stmt); |
| struct loop *max_loop; |
| struct depend *dep; |
| struct lim_aux_data *def_data; |
| |
| if (!def_bb) |
| return true; |
| |
| max_loop = outermost_invariant_loop (def, loop); |
| if (!max_loop) |
| return false; |
| |
| if (flow_loop_nested_p (data->max_loop, max_loop)) |
| data->max_loop = max_loop; |
| |
| def_data = get_lim_data (def_stmt); |
| if (!def_data) |
| return true; |
| |
| if (add_cost |
| /* Only add the cost if the statement defining DEF is inside LOOP, |
| i.e. if it is likely that by moving the invariants dependent |
| on it, we will be able to avoid creating a new register for |
| it (since it will be only used in these dependent invariants). */ |
| && def_bb->loop_father == loop) |
| data->cost += def_data->cost; |
| |
| dep = XNEW (struct depend); |
| dep->stmt = def_stmt; |
| dep->next = data->depends; |
| data->depends = dep; |
| |
| return true; |
| } |
| |
| /* Returns an estimate for a cost of statement STMT. TODO -- the values here |
| are just ad-hoc constants. The estimates should be based on target-specific |
| values. */ |
| |
| static unsigned |
| stmt_cost (gimple stmt) |
| { |
| tree fndecl; |
| unsigned cost = 1; |
| |
| /* Always try to create possibilities for unswitching. */ |
| if (gimple_code (stmt) == GIMPLE_COND) |
| return LIM_EXPENSIVE; |
| |
| /* Hoisting memory references out should almost surely be a win. */ |
| if (gimple_references_memory_p (stmt)) |
| cost += 20; |
| |
| if (is_gimple_call (stmt)) |
| { |
| /* We should be hoisting calls if possible. */ |
| |
| /* Unless the call is a builtin_constant_p; this always folds to a |
| constant, so moving it is useless. */ |
| fndecl = gimple_call_fndecl (stmt); |
| if (fndecl |
| && DECL_BUILT_IN_CLASS (fndecl) == BUILT_IN_NORMAL |
| && DECL_FUNCTION_CODE (fndecl) == BUILT_IN_CONSTANT_P) |
| return 0; |
| |
| return cost + 20; |
| } |
| |
| if (gimple_code (stmt) != GIMPLE_ASSIGN) |
| return cost; |
| |
| switch (gimple_assign_rhs_code (stmt)) |
| { |
| case MULT_EXPR: |
| case TRUNC_DIV_EXPR: |
| case CEIL_DIV_EXPR: |
| case FLOOR_DIV_EXPR: |
| case ROUND_DIV_EXPR: |
| case EXACT_DIV_EXPR: |
| case CEIL_MOD_EXPR: |
| case FLOOR_MOD_EXPR: |
| case ROUND_MOD_EXPR: |
| case TRUNC_MOD_EXPR: |
| case RDIV_EXPR: |
| /* Division and multiplication are usually expensive. */ |
| cost += 20; |
| break; |
| |
| case LSHIFT_EXPR: |
| case RSHIFT_EXPR: |
| cost += 20; |
| break; |
| |
| default: |
| break; |
| } |
| |
| return cost; |
| } |
| |
| /* Finds the outermost loop between OUTER and LOOP in that the memory reference |
| REF is independent. If REF is not independent in LOOP, NULL is returned |
| instead. */ |
| |
| static struct loop * |
| outermost_indep_loop (struct loop *outer, struct loop *loop, mem_ref_p ref) |
| { |
| struct loop *aloop; |
| |
| if (bitmap_bit_p (ref->stored, loop->num)) |
| return NULL; |
| |
| for (aloop = outer; |
| aloop != loop; |
| aloop = superloop_at_depth (loop, loop_depth (aloop) + 1)) |
| if (!bitmap_bit_p (ref->stored, aloop->num) |
| && ref_indep_loop_p (aloop, ref)) |
| return aloop; |
| |
| if (ref_indep_loop_p (loop, ref)) |
| return loop; |
| else |
| return NULL; |
| } |
| |
| /* If there is a simple load or store to a memory reference in STMT, returns |
| the location of the memory reference, and sets IS_STORE according to whether |
| it is a store or load. Otherwise, returns NULL. */ |
| |
| static tree * |
| simple_mem_ref_in_stmt (gimple stmt, bool *is_store) |
| { |
| tree *lhs; |
| enum tree_code code; |
| |
| /* Recognize MEM = (SSA_NAME | invariant) and SSA_NAME = MEM patterns. */ |
| if (gimple_code (stmt) != GIMPLE_ASSIGN) |
| return NULL; |
| |
| code = gimple_assign_rhs_code (stmt); |
| |
| lhs = gimple_assign_lhs_ptr (stmt); |
| |
| if (TREE_CODE (*lhs) == SSA_NAME) |
| { |
| if (get_gimple_rhs_class (code) != GIMPLE_SINGLE_RHS |
| || !is_gimple_addressable (gimple_assign_rhs1 (stmt))) |
| return NULL; |
| |
| *is_store = false; |
| return gimple_assign_rhs1_ptr (stmt); |
| } |
| else if (code == SSA_NAME |
| || (get_gimple_rhs_class (code) == GIMPLE_SINGLE_RHS |
| && is_gimple_min_invariant (gimple_assign_rhs1 (stmt)))) |
| { |
| *is_store = true; |
| return lhs; |
| } |
| else |
| return NULL; |
| } |
| |
| /* Returns the memory reference contained in STMT. */ |
| |
| static mem_ref_p |
| mem_ref_in_stmt (gimple stmt) |
| { |
| bool store; |
| tree *mem = simple_mem_ref_in_stmt (stmt, &store); |
| hashval_t hash; |
| mem_ref_p ref; |
| |
| if (!mem) |
| return NULL; |
| gcc_assert (!store); |
| |
| hash = iterative_hash_expr (*mem, 0); |
| ref = (mem_ref_p) htab_find_with_hash (memory_accesses.refs, *mem, hash); |
| |
| gcc_assert (ref != NULL); |
| return ref; |
| } |
| |
| /* Determine the outermost loop to that it is possible to hoist a statement |
| STMT and store it to LIM_DATA (STMT)->max_loop. To do this we determine |
| the outermost loop in that the value computed by STMT is invariant. |
| If MUST_PRESERVE_EXEC is true, additionally choose such a loop that |
| we preserve the fact whether STMT is executed. It also fills other related |
| information to LIM_DATA (STMT). |
| |
| The function returns false if STMT cannot be hoisted outside of the loop it |
| is defined in, and true otherwise. */ |
| |
| static bool |
| determine_max_movement (gimple stmt, bool must_preserve_exec) |
| { |
| basic_block bb = gimple_bb (stmt); |
| struct loop *loop = bb->loop_father; |
| struct loop *level; |
| struct lim_aux_data *lim_data = get_lim_data (stmt); |
| tree val; |
| ssa_op_iter iter; |
| |
| if (must_preserve_exec) |
| level = ALWAYS_EXECUTED_IN (bb); |
| else |
| level = superloop_at_depth (loop, 1); |
| lim_data->max_loop = level; |
| |
| FOR_EACH_SSA_TREE_OPERAND (val, stmt, iter, SSA_OP_USE) |
| if (!add_dependency (val, lim_data, loop, true)) |
| return false; |
| |
| if (!ZERO_SSA_OPERANDS (stmt, SSA_OP_VIRTUAL_USES)) |
| { |
| mem_ref_p ref = mem_ref_in_stmt (stmt); |
| |
| if (ref) |
| { |
| lim_data->max_loop |
| = outermost_indep_loop (lim_data->max_loop, loop, ref); |
| if (!lim_data->max_loop) |
| return false; |
| } |
| else |
| { |
| FOR_EACH_SSA_TREE_OPERAND (val, stmt, iter, SSA_OP_VIRTUAL_USES) |
| { |
| if (!add_dependency (val, lim_data, loop, false)) |
| return false; |
| } |
| } |
| } |
| |
| lim_data->cost += stmt_cost (stmt); |
| |
| return true; |
| } |
| |
| /* Suppose that some statement in ORIG_LOOP is hoisted to the loop LEVEL, |
| and that one of the operands of this statement is computed by STMT. |
| Ensure that STMT (together with all the statements that define its |
| operands) is hoisted at least out of the loop LEVEL. */ |
| |
| static void |
| set_level (gimple stmt, struct loop *orig_loop, struct loop *level) |
| { |
| struct loop *stmt_loop = gimple_bb (stmt)->loop_father; |
| struct depend *dep; |
| struct lim_aux_data *lim_data; |
| |
| stmt_loop = find_common_loop (orig_loop, stmt_loop); |
| lim_data = get_lim_data (stmt); |
| if (lim_data != NULL && lim_data->tgt_loop != NULL) |
| stmt_loop = find_common_loop (stmt_loop, |
| loop_outer (lim_data->tgt_loop)); |
| if (flow_loop_nested_p (stmt_loop, level)) |
| return; |
| |
| gcc_assert (level == lim_data->max_loop |
| || flow_loop_nested_p (lim_data->max_loop, level)); |
| |
| lim_data->tgt_loop = level; |
| for (dep = lim_data->depends; dep; dep = dep->next) |
| set_level (dep->stmt, orig_loop, level); |
| } |
| |
| /* Determines an outermost loop from that we want to hoist the statement STMT. |
| For now we chose the outermost possible loop. TODO -- use profiling |
| information to set it more sanely. */ |
| |
| static void |
| set_profitable_level (gimple stmt) |
| { |
| set_level (stmt, gimple_bb (stmt)->loop_father, get_lim_data (stmt)->max_loop); |
| } |
| |
| /* Returns true if STMT is a call that has side effects. */ |
| |
| static bool |
| nonpure_call_p (gimple stmt) |
| { |
| if (gimple_code (stmt) != GIMPLE_CALL) |
| return false; |
| |
| return gimple_has_side_effects (stmt); |
| } |
| |
| /* Rewrite a/b to a*(1/b). Return the invariant stmt to process. */ |
| |
| static gimple |
| rewrite_reciprocal (gimple_stmt_iterator *bsi) |
| { |
| gimple stmt, stmt1, stmt2; |
| tree var, name, lhs, type; |
| tree real_one; |
| |
| stmt = gsi_stmt (*bsi); |
| lhs = gimple_assign_lhs (stmt); |
| type = TREE_TYPE (lhs); |
| |
| var = create_tmp_var (type, "reciptmp"); |
| add_referenced_var (var); |
| DECL_GIMPLE_REG_P (var) = 1; |
| |
| /* For vectors, create a VECTOR_CST full of 1's. */ |
| if (TREE_CODE (type) == VECTOR_TYPE) |
| { |
| int i, len; |
| tree list = NULL_TREE; |
| real_one = build_real (TREE_TYPE (type), dconst1); |
| len = TYPE_VECTOR_SUBPARTS (type); |
| for (i = 0; i < len; i++) |
| list = tree_cons (NULL, real_one, list); |
| real_one = build_vector (type, list); |
| } |
| else |
| real_one = build_real (type, dconst1); |
| |
| stmt1 = gimple_build_assign_with_ops (RDIV_EXPR, |
| var, real_one, gimple_assign_rhs2 (stmt)); |
| name = make_ssa_name (var, stmt1); |
| gimple_assign_set_lhs (stmt1, name); |
| |
| stmt2 = gimple_build_assign_with_ops (MULT_EXPR, lhs, name, |
| gimple_assign_rhs1 (stmt)); |
| |
| /* Replace division stmt with reciprocal and multiply stmts. |
| The multiply stmt is not invariant, so update iterator |
| and avoid rescanning. */ |
| gsi_replace (bsi, stmt1, true); |
| gsi_insert_after (bsi, stmt2, GSI_NEW_STMT); |
| |
| /* Continue processing with invariant reciprocal statement. */ |
| return stmt1; |
| } |
| |
| /* Check if the pattern at *BSI is a bittest of the form |
| (A >> B) & 1 != 0 and in this case rewrite it to A & (1 << B) != 0. */ |
| |
| static gimple |
| rewrite_bittest (gimple_stmt_iterator *bsi) |
| { |
| gimple stmt, use_stmt, stmt1, stmt2; |
| tree lhs, var, name, t, a, b; |
| use_operand_p use; |
| |
| stmt = gsi_stmt (*bsi); |
| lhs = gimple_assign_lhs (stmt); |
| |
| /* Verify that the single use of lhs is a comparison against zero. */ |
| if (TREE_CODE (lhs) != SSA_NAME |
| || !single_imm_use (lhs, &use, &use_stmt) |
| || gimple_code (use_stmt) != GIMPLE_COND) |
| return stmt; |
| if (gimple_cond_lhs (use_stmt) != lhs |
| || (gimple_cond_code (use_stmt) != NE_EXPR |
| && gimple_cond_code (use_stmt) != EQ_EXPR) |
| || !integer_zerop (gimple_cond_rhs (use_stmt))) |
| return stmt; |
| |
| /* Get at the operands of the shift. The rhs is TMP1 & 1. */ |
| stmt1 = SSA_NAME_DEF_STMT (gimple_assign_rhs1 (stmt)); |
| if (gimple_code (stmt1) != GIMPLE_ASSIGN) |
| return stmt; |
| |
| /* There is a conversion in between possibly inserted by fold. */ |
| if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (stmt1))) |
| { |
| t = gimple_assign_rhs1 (stmt1); |
| if (TREE_CODE (t) != SSA_NAME |
| || !has_single_use (t)) |
| return stmt; |
| stmt1 = SSA_NAME_DEF_STMT (t); |
| if (gimple_code (stmt1) != GIMPLE_ASSIGN) |
| return stmt; |
| } |
| |
| /* Verify that B is loop invariant but A is not. Verify that with |
| all the stmt walking we are still in the same loop. */ |
| if (gimple_assign_rhs_code (stmt1) != RSHIFT_EXPR |
| || loop_containing_stmt (stmt1) != loop_containing_stmt (stmt)) |
| return stmt; |
| |
| a = gimple_assign_rhs1 (stmt1); |
| b = gimple_assign_rhs2 (stmt1); |
| |
| if (outermost_invariant_loop (b, loop_containing_stmt (stmt1)) != NULL |
| && outermost_invariant_loop (a, loop_containing_stmt (stmt1)) == NULL) |
| { |
| /* 1 << B */ |
| var = create_tmp_var (TREE_TYPE (a), "shifttmp"); |
| add_referenced_var (var); |
| t = fold_build2 (LSHIFT_EXPR, TREE_TYPE (a), |
| build_int_cst (TREE_TYPE (a), 1), b); |
| stmt1 = gimple_build_assign (var, t); |
| name = make_ssa_name (var, stmt1); |
| gimple_assign_set_lhs (stmt1, name); |
| |
| /* A & (1 << B) */ |
| t = fold_build2 (BIT_AND_EXPR, TREE_TYPE (a), a, name); |
| stmt2 = gimple_build_assign (var, t); |
| name = make_ssa_name (var, stmt2); |
| gimple_assign_set_lhs (stmt2, name); |
| |
| /* Replace the SSA_NAME we compare against zero. Adjust |
| the type of zero accordingly. */ |
| SET_USE (use, name); |
| gimple_cond_set_rhs (use_stmt, build_int_cst_type (TREE_TYPE (name), 0)); |
| |
| gsi_insert_before (bsi, stmt1, GSI_SAME_STMT); |
| gsi_replace (bsi, stmt2, true); |
| |
| return stmt1; |
| } |
| |
| return stmt; |
| } |
| |
| |
| /* Determine the outermost loops in that statements in basic block BB are |
| invariant, and record them to the LIM_DATA associated with the statements. |
| Callback for walk_dominator_tree. */ |
| |
| static void |
| determine_invariantness_stmt (struct dom_walk_data *dw_data ATTRIBUTE_UNUSED, |
| basic_block bb) |
| { |
| enum move_pos pos; |
| gimple_stmt_iterator bsi; |
| gimple stmt; |
| bool maybe_never = ALWAYS_EXECUTED_IN (bb) == NULL; |
| struct loop *outermost = ALWAYS_EXECUTED_IN (bb); |
| struct lim_aux_data *lim_data; |
| |
| if (!loop_outer (bb->loop_father)) |
| return; |
| |
| if (dump_file && (dump_flags & TDF_DETAILS)) |
| fprintf (dump_file, "Basic block %d (loop %d -- depth %d):\n\n", |
| bb->index, bb->loop_father->num, loop_depth (bb->loop_father)); |
| |
| for (bsi = gsi_start_bb (bb); !gsi_end_p (bsi); gsi_next (&bsi)) |
| { |
| stmt = gsi_stmt (bsi); |
| |
| pos = movement_possibility (stmt); |
| if (pos == MOVE_IMPOSSIBLE) |
| { |
| if (nonpure_call_p (stmt)) |
| { |
| maybe_never = true; |
| outermost = NULL; |
| } |
| /* Make sure to note always_executed_in for stores to make |
| store-motion work. */ |
| else if (stmt_makes_single_store (stmt)) |
| { |
| struct lim_aux_data *lim_data = init_lim_data (stmt); |
| lim_data->always_executed_in = outermost; |
| } |
| continue; |
| } |
| |
| if (is_gimple_assign (stmt) |
| && (get_gimple_rhs_class (gimple_assign_rhs_code (stmt)) |
| == GIMPLE_BINARY_RHS)) |
| { |
| tree op0 = gimple_assign_rhs1 (stmt); |
| tree op1 = gimple_assign_rhs2 (stmt); |
| struct loop *ol1 = outermost_invariant_loop (op1, |
| loop_containing_stmt (stmt)); |
| |
| /* If divisor is invariant, convert a/b to a*(1/b), allowing reciprocal |
| to be hoisted out of loop, saving expensive divide. */ |
| if (pos == MOVE_POSSIBLE |
| && gimple_assign_rhs_code (stmt) == RDIV_EXPR |
| && flag_unsafe_math_optimizations |
| && !flag_trapping_math |
| && ol1 != NULL |
| && outermost_invariant_loop (op0, ol1) == NULL) |
| stmt = rewrite_reciprocal (&bsi); |
| |
| /* If the shift count is invariant, convert (A >> B) & 1 to |
| A & (1 << B) allowing the bit mask to be hoisted out of the loop |
| saving an expensive shift. */ |
| if (pos == MOVE_POSSIBLE |
| && gimple_assign_rhs_code (stmt) == BIT_AND_EXPR |
| && integer_onep (op1) |
| && TREE_CODE (op0) == SSA_NAME |
| && has_single_use (op0)) |
| stmt = rewrite_bittest (&bsi); |
| } |
| |
| lim_data = init_lim_data (stmt); |
| lim_data->always_executed_in = outermost; |
| |
| if (maybe_never && pos == MOVE_PRESERVE_EXECUTION) |
| continue; |
| |
| if (!determine_max_movement (stmt, pos == MOVE_PRESERVE_EXECUTION)) |
| { |
| lim_data->max_loop = NULL; |
| continue; |
| } |
| |
| if (dump_file && (dump_flags & TDF_DETAILS)) |
| { |
| print_gimple_stmt (dump_file, stmt, 2, 0); |
| fprintf (dump_file, " invariant up to level %d, cost %d.\n\n", |
| loop_depth (lim_data->max_loop), |
| lim_data->cost); |
| } |
| |
| if (lim_data->cost >= LIM_EXPENSIVE) |
| set_profitable_level (stmt); |
| } |
| } |
| |
| /* For each statement determines the outermost loop in that it is invariant, |
| statements on whose motion it depends and the cost of the computation. |
| This information is stored to the LIM_DATA structure associated with |
| each statement. */ |
| |
| static void |
| determine_invariantness (void) |
| { |
| struct dom_walk_data walk_data; |
| |
| memset (&walk_data, 0, sizeof (struct dom_walk_data)); |
| walk_data.dom_direction = CDI_DOMINATORS; |
| walk_data.before_dom_children_before_stmts = determine_invariantness_stmt; |
| |
| init_walk_dominator_tree (&walk_data); |
| walk_dominator_tree (&walk_data, ENTRY_BLOCK_PTR); |
| fini_walk_dominator_tree (&walk_data); |
| } |
| |
| /* Hoist the statements in basic block BB out of the loops prescribed by |
| data stored in LIM_DATA structures associated with each statement. Callback |
| for walk_dominator_tree. */ |
| |
| static void |
| move_computations_stmt (struct dom_walk_data *dw_data ATTRIBUTE_UNUSED, |
| basic_block bb) |
| { |
| struct loop *level; |
| gimple_stmt_iterator bsi; |
| gimple stmt; |
| unsigned cost = 0; |
| struct lim_aux_data *lim_data; |
| |
| if (!loop_outer (bb->loop_father)) |
| return; |
| |
| for (bsi = gsi_start_bb (bb); !gsi_end_p (bsi); ) |
| { |
| stmt = gsi_stmt (bsi); |
| |
| lim_data = get_lim_data (stmt); |
| if (lim_data == NULL) |
| { |
| gsi_next (&bsi); |
| continue; |
| } |
| |
| cost = lim_data->cost; |
| level = lim_data->tgt_loop; |
| clear_lim_data (stmt); |
| |
| if (!level) |
| { |
| gsi_next (&bsi); |
| continue; |
| } |
| |
| /* We do not really want to move conditionals out of the loop; we just |
| placed it here to force its operands to be moved if necessary. */ |
| if (gimple_code (stmt) == GIMPLE_COND) |
| continue; |
| |
| if (dump_file && (dump_flags & TDF_DETAILS)) |
| { |
| fprintf (dump_file, "Moving statement\n"); |
| print_gimple_stmt (dump_file, stmt, 0, 0); |
| fprintf (dump_file, "(cost %u) out of loop %d.\n\n", |
| cost, level->num); |
| } |
| |
| mark_virtual_ops_for_renaming (stmt); |
| gsi_insert_on_edge (loop_preheader_edge (level), stmt); |
| gsi_remove (&bsi, false); |
| } |
| } |
| |
| /* Hoist the statements out of the loops prescribed by data stored in |
| LIM_DATA structures associated with each statement.*/ |
| |
| static void |
| move_computations (void) |
| { |
| struct dom_walk_data walk_data; |
| |
| memset (&walk_data, 0, sizeof (struct dom_walk_data)); |
| walk_data.dom_direction = CDI_DOMINATORS; |
| walk_data.before_dom_children_before_stmts = move_computations_stmt; |
| |
| init_walk_dominator_tree (&walk_data); |
| walk_dominator_tree (&walk_data, ENTRY_BLOCK_PTR); |
| fini_walk_dominator_tree (&walk_data); |
| |
| gsi_commit_edge_inserts (); |
| if (need_ssa_update_p ()) |
| rewrite_into_loop_closed_ssa (NULL, TODO_update_ssa); |
| } |
| |
| /* Checks whether the statement defining variable *INDEX can be hoisted |
| out of the loop passed in DATA. Callback for for_each_index. */ |
| |
| static bool |
| may_move_till (tree ref, tree *index, void *data) |
| { |
| struct loop *loop = (struct loop *) data, *max_loop; |
| |
| /* If REF is an array reference, check also that the step and the lower |
| bound is invariant in LOOP. */ |
| if (TREE_CODE (ref) == ARRAY_REF) |
| { |
| tree step = TREE_OPERAND (ref, 3); |
| tree lbound = TREE_OPERAND (ref, 2); |
| |
| max_loop = outermost_invariant_loop (step, loop); |
| if (!max_loop) |
| return false; |
| |
| max_loop = outermost_invariant_loop (lbound, loop); |
| if (!max_loop) |
| return false; |
| } |
| |
| max_loop = outermost_invariant_loop (*index, loop); |
| if (!max_loop) |
| return false; |
| |
| return true; |
| } |
| |
| /* If OP is SSA NAME, force the statement that defines it to be |
| moved out of the LOOP. ORIG_LOOP is the loop in that EXPR is used. */ |
| |
| static void |
| force_move_till_op (tree op, struct loop *orig_loop, struct loop *loop) |
| { |
| gimple stmt; |
| |
| if (!op |
| || is_gimple_min_invariant (op)) |
| return; |
| |
| gcc_assert (TREE_CODE (op) == SSA_NAME); |
| |
| stmt = SSA_NAME_DEF_STMT (op); |
| if (gimple_nop_p (stmt)) |
| return; |
| |
| set_level (stmt, orig_loop, loop); |
| } |
| |
| /* Forces statement defining invariants in REF (and *INDEX) to be moved out of |
| the LOOP. The reference REF is used in the loop ORIG_LOOP. Callback for |
| for_each_index. */ |
| |
| struct fmt_data |
| { |
| struct loop *loop; |
| struct loop *orig_loop; |
| }; |
| |
| static bool |
| force_move_till (tree ref, tree *index, void *data) |
| { |
| struct fmt_data *fmt_data = (struct fmt_data *) data; |
| |
| if (TREE_CODE (ref) == ARRAY_REF) |
| { |
| tree step = TREE_OPERAND (ref, 3); |
| tree lbound = TREE_OPERAND (ref, 2); |
| |
| force_move_till_op (step, fmt_data->orig_loop, fmt_data->loop); |
| force_move_till_op (lbound, fmt_data->orig_loop, fmt_data->loop); |
| } |
| |
| force_move_till_op (*index, fmt_data->orig_loop, fmt_data->loop); |
| |
| return true; |
| } |
| |
| /* A hash function for struct mem_ref object OBJ. */ |
| |
| static hashval_t |
| memref_hash (const void *obj) |
| { |
| const struct mem_ref *const mem = (const struct mem_ref *) obj; |
| |
| return mem->hash; |
| } |
| |
| /* An equality function for struct mem_ref object OBJ1 with |
| memory reference OBJ2. */ |
| |
| static int |
| memref_eq (const void *obj1, const void *obj2) |
| { |
| const struct mem_ref *const mem1 = (const struct mem_ref *) obj1; |
| |
| return operand_equal_p (mem1->mem, (const_tree) obj2, 0); |
| } |
| |
| /* Releases list of memory reference locations ACCS. */ |
| |
| static void |
| free_mem_ref_locs (mem_ref_locs_p accs) |
| { |
| unsigned i; |
| mem_ref_loc_p loc; |
| |
| if (!accs) |
| return; |
| |
| for (i = 0; VEC_iterate (mem_ref_loc_p, accs->locs, i, loc); i++) |
| free (loc); |
| VEC_free (mem_ref_loc_p, heap, accs->locs); |
| free (accs); |
| } |
| |
| /* A function to free the mem_ref object OBJ. */ |
| |
| static void |
| memref_free (void *obj) |
| { |
| struct mem_ref *const mem = (struct mem_ref *) obj; |
| unsigned i; |
| mem_ref_locs_p accs; |
| |
| BITMAP_FREE (mem->stored); |
| BITMAP_FREE (mem->indep_loop); |
| BITMAP_FREE (mem->dep_loop); |
| BITMAP_FREE (mem->indep_ref); |
| BITMAP_FREE (mem->dep_ref); |
| |
| for (i = 0; VEC_iterate (mem_ref_locs_p, mem->accesses_in_loop, i, accs); i++) |
| free_mem_ref_locs (accs); |
| VEC_free (mem_ref_locs_p, heap, mem->accesses_in_loop); |
| |
| BITMAP_FREE (mem->vops); |
| free (mem); |
| } |
| |
| /* Allocates and returns a memory reference description for MEM whose hash |
| value is HASH and id is ID. */ |
| |
| static mem_ref_p |
| mem_ref_alloc (tree mem, unsigned hash, unsigned id) |
| { |
| mem_ref_p ref = XNEW (struct mem_ref); |
| ref->mem = mem; |
| ref->id = id; |
| ref->hash = hash; |
| ref->stored = BITMAP_ALLOC (NULL); |
| ref->indep_loop = BITMAP_ALLOC (NULL); |
| ref->dep_loop = BITMAP_ALLOC (NULL); |
| ref->indep_ref = BITMAP_ALLOC (NULL); |
| ref->dep_ref = BITMAP_ALLOC (NULL); |
| ref->accesses_in_loop = NULL; |
| ref->vops = BITMAP_ALLOC (NULL); |
| |
| return ref; |
| } |
| |
| /* Allocates and returns the new list of locations. */ |
| |
| static mem_ref_locs_p |
| mem_ref_locs_alloc (void) |
| { |
| mem_ref_locs_p accs = XNEW (struct mem_ref_locs); |
| accs->locs = NULL; |
| return accs; |
| } |
| |
| /* Records memory reference location *LOC in LOOP to the memory reference |
| description REF. The reference occurs in statement STMT. */ |
| |
| static void |
| record_mem_ref_loc (mem_ref_p ref, struct loop *loop, gimple stmt, tree *loc) |
| { |
| mem_ref_loc_p aref = XNEW (struct mem_ref_loc); |
| mem_ref_locs_p accs; |
| bitmap ril = VEC_index (bitmap, memory_accesses.refs_in_loop, loop->num); |
| |
| if (VEC_length (mem_ref_locs_p, ref->accesses_in_loop) |
| <= (unsigned) loop->num) |
| VEC_safe_grow_cleared (mem_ref_locs_p, heap, ref->accesses_in_loop, |
| loop->num + 1); |
| accs = VEC_index (mem_ref_locs_p, ref->accesses_in_loop, loop->num); |
| if (!accs) |
| { |
| accs = mem_ref_locs_alloc (); |
| VEC_replace (mem_ref_locs_p, ref->accesses_in_loop, loop->num, accs); |
| } |
| |
| aref->stmt = stmt; |
| aref->ref = loc; |
| |
| VEC_safe_push (mem_ref_loc_p, heap, accs->locs, aref); |
| bitmap_set_bit (ril, ref->id); |
| } |
| |
| /* Marks reference REF as stored in LOOP. */ |
| |
| static void |
| mark_ref_stored (mem_ref_p ref, struct loop *loop) |
| { |
| for (; |
| loop != current_loops->tree_root |
| && !bitmap_bit_p (ref->stored, loop->num); |
| loop = loop_outer (loop)) |
| bitmap_set_bit (ref->stored, loop->num); |
| } |
| |
| /* Gathers memory references in statement STMT in LOOP, storing the |
| information about them in the memory_accesses structure. Marks |
| the vops accessed through unrecognized statements there as |
| well. */ |
| |
| static void |
| gather_mem_refs_stmt (struct loop *loop, gimple stmt) |
| { |
| tree *mem = NULL; |
| hashval_t hash; |
| PTR *slot; |
| mem_ref_p ref; |
| ssa_op_iter oi; |
| tree vname; |
| bool is_stored; |
| bitmap clvops; |
| unsigned id; |
| |
| if (ZERO_SSA_OPERANDS (stmt, SSA_OP_ALL_VIRTUALS)) |
| return; |
| |
| mem = simple_mem_ref_in_stmt (stmt, &is_stored); |
| if (!mem) |
| goto fail; |
| |
| hash = iterative_hash_expr (*mem, 0); |
| slot = htab_find_slot_with_hash (memory_accesses.refs, *mem, hash, INSERT); |
| |
| if (*slot) |
| { |
| ref = (mem_ref_p) *slot; |
| id = ref->id; |
| } |
| else |
| { |
| id = VEC_length (mem_ref_p, memory_accesses.refs_list); |
| ref = mem_ref_alloc (*mem, hash, id); |
| VEC_safe_push (mem_ref_p, heap, memory_accesses.refs_list, ref); |
| *slot = ref; |
| |
| if (dump_file && (dump_flags & TDF_DETAILS)) |
| { |
| fprintf (dump_file, "Memory reference %u: ", id); |
| print_generic_expr (dump_file, ref->mem, TDF_SLIM); |
| fprintf (dump_file, "\n"); |
| } |
| } |
| if (is_stored) |
| mark_ref_stored (ref, loop); |
| |
| FOR_EACH_SSA_TREE_OPERAND (vname, stmt, oi, SSA_OP_VIRTUAL_USES) |
| bitmap_set_bit (ref->vops, DECL_UID (SSA_NAME_VAR (vname))); |
| record_mem_ref_loc (ref, loop, stmt, mem); |
| return; |
| |
| fail: |
| clvops = VEC_index (bitmap, memory_accesses.clobbered_vops, loop->num); |
| FOR_EACH_SSA_TREE_OPERAND (vname, stmt, oi, SSA_OP_VIRTUAL_USES) |
| bitmap_set_bit (clvops, DECL_UID (SSA_NAME_VAR (vname))); |
| } |
| |
| /* Gathers memory references in loops. */ |
| |
| static void |
| gather_mem_refs_in_loops (void) |
| { |
| gimple_stmt_iterator bsi; |
| basic_block bb; |
| struct loop *loop; |
| loop_iterator li; |
| bitmap clvo, clvi; |
| bitmap lrefs, alrefs, alrefso; |
| |
| FOR_EACH_BB (bb) |
| { |
| loop = bb->loop_father; |
| if (loop == current_loops->tree_root) |
| continue; |
| |
| for (bsi = gsi_start_bb (bb); !gsi_end_p (bsi); gsi_next (&bsi)) |
| gather_mem_refs_stmt (loop, gsi_stmt (bsi)); |
| } |
| |
| /* Propagate the information about clobbered vops and accessed memory |
| references up the loop hierarchy. */ |
| FOR_EACH_LOOP (li, loop, LI_FROM_INNERMOST) |
| { |
| lrefs = VEC_index (bitmap, memory_accesses.refs_in_loop, loop->num); |
| alrefs = VEC_index (bitmap, memory_accesses.all_refs_in_loop, loop->num); |
| bitmap_ior_into (alrefs, lrefs); |
| |
| if (loop_outer (loop) == current_loops->tree_root) |
| continue; |
| |
| clvi = VEC_index (bitmap, memory_accesses.clobbered_vops, loop->num); |
| clvo = VEC_index (bitmap, memory_accesses.clobbered_vops, |
| loop_outer (loop)->num); |
| bitmap_ior_into (clvo, clvi); |
| |
| alrefso = VEC_index (bitmap, memory_accesses.all_refs_in_loop, |
| loop_outer (loop)->num); |
| bitmap_ior_into (alrefso, alrefs); |
| } |
| } |
| |
| /* Element of the hash table that maps vops to memory references. */ |
| |
| struct vop_to_refs_elt |
| { |
| /* DECL_UID of the vop. */ |
| unsigned uid; |
| |
| /* List of the all references. */ |
| bitmap refs_all; |
| |
| /* List of stored references. */ |
| bitmap refs_stored; |
| }; |
| |
| /* A hash function for struct vop_to_refs_elt object OBJ. */ |
| |
| static hashval_t |
| vtoe_hash (const void *obj) |
| { |
| const struct vop_to_refs_elt *const vtoe = |
| (const struct vop_to_refs_elt *) obj; |
| |
| return vtoe->uid; |
| } |
| |
| /* An equality function for struct vop_to_refs_elt object OBJ1 with |
| uid of a vop OBJ2. */ |
| |
| static int |
| vtoe_eq (const void *obj1, const void *obj2) |
| { |
| const struct vop_to_refs_elt *const vtoe = |
| (const struct vop_to_refs_elt *) obj1; |
| const unsigned *const uid = (const unsigned *) obj2; |
| |
| return vtoe->uid == *uid; |
| } |
| |
| /* A function to free the struct vop_to_refs_elt object. */ |
| |
| static void |
| vtoe_free (void *obj) |
| { |
| struct vop_to_refs_elt *const vtoe = |
| (struct vop_to_refs_elt *) obj; |
| |
| BITMAP_FREE (vtoe->refs_all); |
| BITMAP_FREE (vtoe->refs_stored); |
| free (vtoe); |
| } |
| |
| /* Records REF to hashtable VOP_TO_REFS for the index VOP. STORED is true |
| if the reference REF is stored. */ |
| |
| static void |
| record_vop_access (htab_t vop_to_refs, unsigned vop, unsigned ref, bool stored) |
| { |
| void **slot = htab_find_slot_with_hash (vop_to_refs, &vop, vop, INSERT); |
| struct vop_to_refs_elt *vtoe; |
| |
| if (!*slot) |
| { |
| vtoe = XNEW (struct vop_to_refs_elt); |
| vtoe->uid = vop; |
| vtoe->refs_all = BITMAP_ALLOC (NULL); |
| vtoe->refs_stored = BITMAP_ALLOC (NULL); |
| *slot = vtoe; |
| } |
| else |
| vtoe = (struct vop_to_refs_elt *) *slot; |
| |
| bitmap_set_bit (vtoe->refs_all, ref); |
| if (stored) |
| bitmap_set_bit (vtoe->refs_stored, ref); |
| } |
| |
| /* Returns the set of references that access VOP according to the table |
| VOP_TO_REFS. */ |
| |
| static bitmap |
| get_vop_accesses (htab_t vop_to_refs, unsigned vop) |
| { |
| struct vop_to_refs_elt *const vtoe = |
| (struct vop_to_refs_elt *) htab_find_with_hash (vop_to_refs, &vop, vop); |
| return vtoe->refs_all; |
| } |
| |
| /* Returns the set of stores that access VOP according to the table |
| VOP_TO_REFS. */ |
| |
| static bitmap |
| get_vop_stores (htab_t vop_to_refs, unsigned vop) |
| { |
| struct vop_to_refs_elt *const vtoe = |
| (struct vop_to_refs_elt *) htab_find_with_hash (vop_to_refs, &vop, vop); |
| return vtoe->refs_stored; |
| } |
| |
| /* Adds REF to mapping from virtual operands to references in LOOP. */ |
| |
| static void |
| add_vop_ref_mapping (struct loop *loop, mem_ref_p ref) |
| { |
| htab_t map = VEC_index (htab_t, memory_accesses.vop_ref_map, loop->num); |
| bool stored = bitmap_bit_p (ref->stored, loop->num); |
| bitmap clobbers = VEC_index (bitmap, memory_accesses.clobbered_vops, |
| loop->num); |
| bitmap_iterator bi; |
| unsigned vop; |
| |
| EXECUTE_IF_AND_COMPL_IN_BITMAP (ref->vops, clobbers, 0, vop, bi) |
| { |
| record_vop_access (map, vop, ref->id, stored); |
| } |
| } |
| |
| /* Create a mapping from virtual operands to references that touch them |
| in LOOP. */ |
| |
| static void |
| create_vop_ref_mapping_loop (struct loop *loop) |
| { |
| bitmap refs = VEC_index (bitmap, memory_accesses.refs_in_loop, loop->num); |
| struct loop *sloop; |
| bitmap_iterator bi; |
| unsigned i; |
| mem_ref_p ref; |
| |
| EXECUTE_IF_SET_IN_BITMAP (refs, 0, i, bi) |
| { |
| ref = VEC_index (mem_ref_p, memory_accesses.refs_list, i); |
| for (sloop = loop; sloop != current_loops->tree_root; sloop = loop_outer (sloop)) |
| add_vop_ref_mapping (sloop, ref); |
| } |
| } |
| |
| /* For each non-clobbered virtual operand and each loop, record the memory |
| references in this loop that touch the operand. */ |
| |
| static void |
| create_vop_ref_mapping (void) |
| { |
| loop_iterator li; |
| struct loop *loop; |
| |
| FOR_EACH_LOOP (li, loop, 0) |
| { |
| create_vop_ref_mapping_loop (loop); |
| } |
| } |
| |
| /* Gathers information about memory accesses in the loops. */ |
| |
| static void |
| analyze_memory_references (void) |
| { |
| unsigned i; |
| bitmap empty; |
| htab_t hempty; |
| |
| memory_accesses.refs |
| = htab_create (100, memref_hash, memref_eq, memref_free); |
| memory_accesses.refs_list = NULL; |
| memory_accesses.refs_in_loop = VEC_alloc (bitmap, heap, |
| number_of_loops ()); |
| memory_accesses.all_refs_in_loop = VEC_alloc (bitmap, heap, |
| number_of_loops ()); |
| memory_accesses.clobbered_vops = VEC_alloc (bitmap, heap, |
| number_of_loops ()); |
| memory_accesses.vop_ref_map = VEC_alloc (htab_t, heap, |
| number_of_loops ()); |
| |
| for (i = 0; i < number_of_loops (); i++) |
| { |
| empty = BITMAP_ALLOC (NULL); |
| VEC_quick_push (bitmap, memory_accesses.refs_in_loop, empty); |
| empty = BITMAP_ALLOC (NULL); |
| VEC_quick_push (bitmap, memory_accesses.all_refs_in_loop, empty); |
| empty = BITMAP_ALLOC (NULL); |
| VEC_quick_push (bitmap, memory_accesses.clobbered_vops, empty); |
| hempty = htab_create (10, vtoe_hash, vtoe_eq, vtoe_free); |
| VEC_quick_push (htab_t, memory_accesses.vop_ref_map, hempty); |
| } |
| |
| memory_accesses.ttae_cache = NULL; |
| |
| gather_mem_refs_in_loops (); |
| create_vop_ref_mapping (); |
| } |
| |
| /* Returns true if a region of size SIZE1 at position 0 and a region of |
| size SIZE2 at position DIFF cannot overlap. */ |
| |
| static bool |
| cannot_overlap_p (aff_tree *diff, double_int size1, double_int size2) |
| { |
| double_int d, bound; |
| |
| /* Unless the difference is a constant, we fail. */ |
| if (diff->n != 0) |
| return false; |
| |
| d = diff->offset; |
| if (double_int_negative_p (d)) |
| { |
| /* The second object is before the first one, we succeed if the last |
| element of the second object is before the start of the first one. */ |
| bound = double_int_add (d, double_int_add (size2, double_int_minus_one)); |
| return double_int_negative_p (bound); |
| } |
| else |
| { |
| /* We succeed if the second object starts after the first one ends. */ |
| return double_int_scmp (size1, d) <= 0; |
| } |
| } |
| |
| /* Returns true if MEM1 and MEM2 may alias. TTAE_CACHE is used as a cache in |
| tree_to_aff_combination_expand. */ |
| |
| static bool |
| mem_refs_may_alias_p (tree mem1, tree mem2, struct pointer_map_t **ttae_cache) |
| { |
| /* Perform BASE + OFFSET analysis -- if MEM1 and MEM2 are based on the same |
| object and their offset differ in such a way that the locations cannot |
| overlap, then they cannot alias. */ |
| double_int size1, size2; |
| aff_tree off1, off2; |
| |
| /* Perform basic offset and type-based disambiguation. */ |
| if (!refs_may_alias_p (mem1, mem2)) |
| return false; |
| |
| /* The expansion of addresses may be a bit expensive, thus we only do |
| the check at -O2 and higher optimization levels. */ |
| if (optimize < 2) |
| return true; |
| |
| get_inner_reference_aff (mem1, &off1, &size1); |
| get_inner_reference_aff (mem2, &off2, &size2); |
| aff_combination_expand (&off1, ttae_cache); |
| aff_combination_expand (&off2, ttae_cache); |
| aff_combination_scale (&off1, double_int_minus_one); |
| aff_combination_add (&off2, &off1); |
| |
| if (cannot_overlap_p (&off2, size1, size2)) |
| return false; |
| |
| return true; |
| } |
| |
| /* Rewrites location LOC by TMP_VAR. */ |
| |
| static void |
| rewrite_mem_ref_loc (mem_ref_loc_p loc, tree tmp_var) |
| { |
| mark_virtual_ops_for_renaming (loc->stmt); |
| *loc->ref = tmp_var; |
| update_stmt (loc->stmt); |
| } |
| |
| /* Adds all locations of REF in LOOP and its subloops to LOCS. */ |
| |
| static void |
| get_all_locs_in_loop (struct loop *loop, mem_ref_p ref, |
| VEC (mem_ref_loc_p, heap) **locs) |
| { |
| mem_ref_locs_p accs; |
| unsigned i; |
| mem_ref_loc_p loc; |
| bitmap refs = VEC_index (bitmap, memory_accesses.all_refs_in_loop, |
| loop->num); |
| struct loop *subloop; |
| |
| if (!bitmap_bit_p (refs, ref->id)) |
| return; |
| |
| if (VEC_length (mem_ref_locs_p, ref->accesses_in_loop) |
| > (unsigned) loop->num) |
| { |
| accs = VEC_index (mem_ref_locs_p, ref->accesses_in_loop, loop->num); |
| if (accs) |
| { |
| for (i = 0; VEC_iterate (mem_ref_loc_p, accs->locs, i, loc); i++) |
| VEC_safe_push (mem_ref_loc_p, heap, *locs, loc); |
| } |
| } |
| |
| for (subloop = loop->inner; subloop != NULL; subloop = subloop->next) |
| get_all_locs_in_loop (subloop, ref, locs); |
| } |
| |
| /* Rewrites all references to REF in LOOP by variable TMP_VAR. */ |
| |
| static void |
| rewrite_mem_refs (struct loop *loop, mem_ref_p ref, tree tmp_var) |
| { |
| unsigned i; |
| mem_ref_loc_p loc; |
| VEC (mem_ref_loc_p, heap) *locs = NULL; |
| |
| get_all_locs_in_loop (loop, ref, &locs); |
| for (i = 0; VEC_iterate (mem_ref_loc_p, locs, i, loc); i++) |
| rewrite_mem_ref_loc (loc, tmp_var); |
| VEC_free (mem_ref_loc_p, heap, locs); |
| } |
| |
| /* The name and the length of the currently generated variable |
| for lsm. */ |
| #define MAX_LSM_NAME_LENGTH 40 |
| static char lsm_tmp_name[MAX_LSM_NAME_LENGTH + 1]; |
| static int lsm_tmp_name_length; |
| |
| /* Adds S to lsm_tmp_name. */ |
| |
| static void |
| lsm_tmp_name_add (const char *s) |
| { |
| int l = strlen (s) + lsm_tmp_name_length; |
| if (l > MAX_LSM_NAME_LENGTH) |
| return; |
| |
| strcpy (lsm_tmp_name + lsm_tmp_name_length, s); |
| lsm_tmp_name_length = l; |
| } |
| |
| /* Stores the name for temporary variable that replaces REF to |
| lsm_tmp_name. */ |
| |
| static void |
| gen_lsm_tmp_name (tree ref) |
| { |
| const char *name; |
| |
| switch (TREE_CODE (ref)) |
| { |
| case MISALIGNED_INDIRECT_REF: |
| case ALIGN_INDIRECT_REF: |
| case INDIRECT_REF: |
| gen_lsm_tmp_name (TREE_OPERAND (ref, 0)); |
| lsm_tmp_name_add ("_"); |
| break; |
| |
| case BIT_FIELD_REF: |
| case VIEW_CONVERT_EXPR: |
| case ARRAY_RANGE_REF: |
| gen_lsm_tmp_name (TREE_OPERAND (ref, 0)); |
| break; |
| |
| case REALPART_EXPR: |
| gen_lsm_tmp_name (TREE_OPERAND (ref, 0)); |
| lsm_tmp_name_add ("_RE"); |
| break; |
| |
| case IMAGPART_EXPR: |
| gen_lsm_tmp_name (TREE_OPERAND (ref, 0)); |
| lsm_tmp_name_add ("_IM"); |
| break; |
| |
| case COMPONENT_REF: |
| gen_lsm_tmp_name (TREE_OPERAND (ref, 0)); |
| lsm_tmp_name_add ("_"); |
| name = get_name (TREE_OPERAND (ref, 1)); |
| if (!name) |
| name = "F"; |
| lsm_tmp_name_add ("_"); |
| lsm_tmp_name_add (name); |
| |
| case ARRAY_REF: |
| gen_lsm_tmp_name (TREE_OPERAND (ref, 0)); |
| lsm_tmp_name_add ("_I"); |
| break; |
| |
| case SSA_NAME: |
| ref = SSA_NAME_VAR (ref); |
| /* Fallthru. */ |
| |
| case VAR_DECL: |
| case PARM_DECL: |
| name = get_name (ref); |
| if (!name) |
| name = "D"; |
| lsm_tmp_name_add (name); |
| break; |
| |
| case STRING_CST: |
| lsm_tmp_name_add ("S"); |
| break; |
| |
| case RESULT_DECL: |
| lsm_tmp_name_add ("R"); |
| break; |
| |
| default: |
| gcc_unreachable (); |
| } |
| } |
| |
| /* Determines name for temporary variable that replaces REF. |
| The name is accumulated into the lsm_tmp_name variable. |
| N is added to the name of the temporary. */ |
| |
| char * |
| get_lsm_tmp_name (tree ref, unsigned n) |
| { |
| char ns[2]; |
| |
| lsm_tmp_name_length = 0; |
| gen_lsm_tmp_name (ref); |
| lsm_tmp_name_add ("_lsm"); |
| if (n < 10) |
| { |
| ns[0] = '0' + n; |
| ns[1] = 0; |
| lsm_tmp_name_add (ns); |
| } |
| return lsm_tmp_name; |
| } |
| |
| /* Executes store motion of memory reference REF from LOOP. |
| Exits from the LOOP are stored in EXITS. The initialization of the |
| temporary variable is put to the preheader of the loop, and assignments |
| to the reference from the temporary variable are emitted to exits. */ |
| |
| static void |
| execute_sm (struct loop *loop, VEC (edge, heap) *exits, mem_ref_p ref) |
| { |
| tree tmp_var; |
| unsigned i; |
| gimple load, store; |
| struct fmt_data fmt_data; |
| edge ex; |
| struct lim_aux_data *lim_data; |
| |
| if (dump_file && (dump_flags & TDF_DETAILS)) |
| { |
| fprintf (dump_file, "Executing store motion of "); |
| print_generic_expr (dump_file, ref->mem, 0); |
| fprintf (dump_file, " from loop %d\n", loop->num); |
| } |
| |
| tmp_var = make_rename_temp (TREE_TYPE (ref->mem), |
| get_lsm_tmp_name (ref->mem, ~0)); |
| |
| fmt_data.loop = loop; |
| fmt_data.orig_loop = loop; |
| for_each_index (&ref->mem, force_move_till, &fmt_data); |
| |
| rewrite_mem_refs (loop, ref, tmp_var); |
| |
| /* Emit the load & stores. */ |
| load = gimple_build_assign (tmp_var, unshare_expr (ref->mem)); |
| lim_data = init_lim_data (load); |
| lim_data->max_loop = loop; |
| lim_data->tgt_loop = loop; |
| |
| /* Put this into the latch, so that we are sure it will be processed after |
| all dependencies. */ |
| gsi_insert_on_edge (loop_latch_edge (loop), load); |
| |
| for (i = 0; VEC_iterate (edge, exits, i, ex); i++) |
| { |
| store = gimple_build_assign (unshare_expr (ref->mem), tmp_var); |
| gsi_insert_on_edge (ex, store); |
| } |
| } |
| |
| /* Hoists memory references MEM_REFS out of LOOP. EXITS is the list of exit |
| edges of the LOOP. */ |
| |
| static void |
| hoist_memory_references (struct loop *loop, bitmap mem_refs, |
| VEC (edge, heap) *exits) |
| { |
| mem_ref_p ref; |
| unsigned i; |
| bitmap_iterator bi; |
| |
| EXECUTE_IF_SET_IN_BITMAP (mem_refs, 0, i, bi) |
| { |
| ref = VEC_index (mem_ref_p, memory_accesses.refs_list, i); |
| execute_sm (loop, exits, ref); |
| } |
| } |
| |
| /* Returns true if REF is always accessed in LOOP. */ |
| |
| static bool |
| ref_always_accessed_p (struct loop *loop, mem_ref_p ref) |
| { |
| VEC (mem_ref_loc_p, heap) *locs = NULL; |
| unsigned i; |
| mem_ref_loc_p loc; |
| bool ret = false; |
| struct loop *must_exec; |
| |
| get_all_locs_in_loop (loop, ref, &locs); |
| for (i = 0; VEC_iterate (mem_ref_loc_p, locs, i, loc); i++) |
| { |
| if (!get_lim_data (loc->stmt)) |
| continue; |
| |
| must_exec = get_lim_data (loc->stmt)->always_executed_in; |
| if (!must_exec) |
| continue; |
| |
| if (must_exec == loop |
| || flow_loop_nested_p (must_exec, loop)) |
| { |
| ret = true; |
| break; |
| } |
| } |
| VEC_free (mem_ref_loc_p, heap, locs); |
| |
| return ret; |
| } |
| |
| /* Returns true if REF1 and REF2 are independent. */ |
| |
| static bool |
| refs_independent_p (mem_ref_p ref1, mem_ref_p ref2) |
| { |
| if (ref1 == ref2 |
| || bitmap_bit_p (ref1->indep_ref, ref2->id)) |
| return true; |
| if (bitmap_bit_p (ref1->dep_ref, ref2->id)) |
| return false; |
| |
| if (dump_file && (dump_flags & TDF_DETAILS)) |
| fprintf (dump_file, "Querying dependency of refs %u and %u: ", |
| ref1->id, ref2->id); |
| |
| if (mem_refs_may_alias_p (ref1->mem, ref2->mem, |
| &memory_accesses.ttae_cache)) |
| { |
| bitmap_set_bit (ref1->dep_ref, ref2->id); |
| bitmap_set_bit (ref2->dep_ref, ref1->id); |
| if (dump_file && (dump_flags & TDF_DETAILS)) |
| fprintf (dump_file, "dependent.\n"); |
| return false; |
| } |
| else |
| { |
| bitmap_set_bit (ref1->indep_ref, ref2->id); |
| bitmap_set_bit (ref2->indep_ref, ref1->id); |
| if (dump_file && (dump_flags & TDF_DETAILS)) |
| fprintf (dump_file, "independent.\n"); |
| return true; |
| } |
| } |
| |
| /* Records the information whether REF is independent in LOOP (according |
| to INDEP). */ |
| |
| static void |
| record_indep_loop (struct loop *loop, mem_ref_p ref, bool indep) |
| { |
| if (indep) |
| bitmap_set_bit (ref->indep_loop, loop->num); |
| else |
| bitmap_set_bit (ref->dep_loop, loop->num); |
| } |
| |
| /* Returns true if REF is independent on all other memory references in |
| LOOP. */ |
| |
| static bool |
| ref_indep_loop_p_1 (struct loop *loop, mem_ref_p ref) |
| { |
| bitmap clobbers, refs_to_check, refs; |
| unsigned i; |
| bitmap_iterator bi; |
| bool ret = true, stored = bitmap_bit_p (ref->stored, loop->num); |
| htab_t map; |
| mem_ref_p aref; |
| |
| /* If the reference is clobbered, it is not independent. */ |
| clobbers = VEC_index (bitmap, memory_accesses.clobbered_vops, loop->num); |
| if (bitmap_intersect_p (ref->vops, clobbers)) |
| return false; |
| |
| refs_to_check = BITMAP_ALLOC (NULL); |
| |
| map = VEC_index (htab_t, memory_accesses.vop_ref_map, loop->num); |
| EXECUTE_IF_AND_COMPL_IN_BITMAP (ref->vops, clobbers, 0, i, bi) |
| { |
| if (stored) |
| refs = get_vop_accesses (map, i); |
| else |
| refs = get_vop_stores (map, i); |
| |
| bitmap_ior_into (refs_to_check, refs); |
| } |
| |
| EXECUTE_IF_SET_IN_BITMAP (refs_to_check, 0, i, bi) |
| { |
| aref = VEC_index (mem_ref_p, memory_accesses.refs_list, i); |
| if (!refs_independent_p (ref, aref)) |
| { |
| ret = false; |
| record_indep_loop (loop, aref, false); |
| break; |
| } |
| } |
| |
| BITMAP_FREE (refs_to_check); |
| return ret; |
| } |
| |
| /* Returns true if REF is independent on all other memory references in |
| LOOP. Wrapper over ref_indep_loop_p_1, caching its results. */ |
| |
| static bool |
| ref_indep_loop_p (struct loop *loop, mem_ref_p ref) |
| { |
| bool ret; |
| |
| if (bitmap_bit_p (ref->indep_loop, loop->num)) |
| return true; |
| if (bitmap_bit_p (ref->dep_loop, loop->num)) |
| return false; |
| |
| ret = ref_indep_loop_p_1 (loop, ref); |
| |
| if (dump_file && (dump_flags & TDF_DETAILS)) |
| fprintf (dump_file, "Querying dependencies of ref %u in loop %d: %s\n", |
| ref->id, loop->num, ret ? "independent" : "dependent"); |
| |
| record_indep_loop (loop, ref, ret); |
| |
| return ret; |
| } |
| |
| /* Returns true if we can perform store motion of REF from LOOP. */ |
| |
| static bool |
| can_sm_ref_p (struct loop *loop, mem_ref_p ref) |
| { |
| /* Unless the reference is stored in the loop, there is nothing to do. */ |
| if (!bitmap_bit_p (ref->stored, loop->num)) |
| return false; |
| |
| /* It should be movable. */ |
| if (!is_gimple_reg_type (TREE_TYPE (ref->mem)) |
| || TREE_THIS_VOLATILE (ref->mem) |
| || !for_each_index (&ref->mem, may_move_till, loop)) |
| return false; |
| |
| /* If it can trap, it must be always executed in LOOP. */ |
| if (tree_could_trap_p (ref->mem) |
| && !ref_always_accessed_p (loop, ref)) |
| return false; |
| |
| /* And it must be independent on all other memory references |
| in LOOP. */ |
| if (!ref_indep_loop_p (loop, ref)) |
| return false; |
| |
| return true; |
| } |
| |
| /* Marks the references in LOOP for that store motion should be performed |
| in REFS_TO_SM. SM_EXECUTED is the set of references for that store |
| motion was performed in one of the outer loops. */ |
| |
| static void |
| find_refs_for_sm (struct loop *loop, bitmap sm_executed, bitmap refs_to_sm) |
| { |
| bitmap refs = VEC_index (bitmap, memory_accesses.all_refs_in_loop, |
| loop->num); |
| unsigned i; |
| bitmap_iterator bi; |
| mem_ref_p ref; |
| |
| EXECUTE_IF_AND_COMPL_IN_BITMAP (refs, sm_executed, 0, i, bi) |
| { |
| ref = VEC_index (mem_ref_p, memory_accesses.refs_list, i); |
| if (can_sm_ref_p (loop, ref)) |
| bitmap_set_bit (refs_to_sm, i); |
| } |
| } |
| |
| /* Checks whether LOOP (with exits stored in EXITS array) is suitable |
| for a store motion optimization (i.e. whether we can insert statement |
| on its exits). */ |
| |
| static bool |
| loop_suitable_for_sm (struct loop *loop ATTRIBUTE_UNUSED, |
| VEC (edge, heap) *exits) |
| { |
| unsigned i; |
| edge ex; |
| |
| for (i = 0; VEC_iterate (edge, exits, i, ex); i++) |
| if (ex->flags & EDGE_ABNORMAL) |
| return false; |
| |
| return true; |
| } |
| |
| /* Try to perform store motion for all memory references modified inside |
| LOOP. SM_EXECUTED is the bitmap of the memory references for that |
| store motion was executed in one of the outer loops. */ |
| |
| static void |
| store_motion_loop (struct loop *loop, bitmap sm_executed) |
| { |
| VEC (edge, heap) *exits = get_loop_exit_edges (loop); |
| struct loop *subloop; |
| bitmap sm_in_loop = BITMAP_ALLOC (NULL); |
| |
| if (loop_suitable_for_sm (loop, exits)) |
| { |
| find_refs_for_sm (loop, sm_executed, sm_in_loop); |
| hoist_memory_references (loop, sm_in_loop, exits); |
| } |
| VEC_free (edge, heap, exits); |
| |
| bitmap_ior_into (sm_executed, sm_in_loop); |
| for (subloop = loop->inner; subloop != NULL; subloop = subloop->next) |
| store_motion_loop (subloop, sm_executed); |
| bitmap_and_compl_into (sm_executed, sm_in_loop); |
| BITMAP_FREE (sm_in_loop); |
| } |
| |
| /* Try to perform store motion for all memory references modified inside |
| loops. */ |
| |
| static void |
| store_motion (void) |
| { |
| struct loop *loop; |
| bitmap sm_executed = BITMAP_ALLOC (NULL); |
| |
| for (loop = current_loops->tree_root->inner; loop != NULL; loop = loop->next) |
| store_motion_loop (loop, sm_executed); |
| |
| BITMAP_FREE (sm_executed); |
| gsi_commit_edge_inserts (); |
| } |
| |
| /* Fills ALWAYS_EXECUTED_IN information for basic blocks of LOOP, i.e. |
| for each such basic block bb records the outermost loop for that execution |
| of its header implies execution of bb. CONTAINS_CALL is the bitmap of |
| blocks that contain a nonpure call. */ |
| |
| static void |
| fill_always_executed_in (struct loop *loop, sbitmap contains_call) |
| { |
| basic_block bb = NULL, *bbs, last = NULL; |
| unsigned i; |
| edge e; |
| struct loop *inn_loop = loop; |
| |
| if (!loop->header->aux) |
| { |
| bbs = get_loop_body_in_dom_order (loop); |
| |
| for (i = 0; i < loop->num_nodes; i++) |
| { |
| edge_iterator ei; |
| bb = bbs[i]; |
| |
| if (dominated_by_p (CDI_DOMINATORS, loop->latch, bb)) |
| last = bb; |
| |
| if (TEST_BIT (contains_call, bb->index)) |
| break; |
| |
| FOR_EACH_EDGE (e, ei, bb->succs) |
| if (!flow_bb_inside_loop_p (loop, e->dest)) |
| break; |
| if (e) |
| break; |
| |
| /* A loop might be infinite (TODO use simple loop analysis |
| to disprove this if possible). */ |
| if (bb->flags & BB_IRREDUCIBLE_LOOP) |
| break; |
| |
| if (!flow_bb_inside_loop_p (inn_loop, bb)) |
| break; |
| |
| if (bb->loop_father->header == bb) |
| { |
| if (!dominated_by_p (CDI_DOMINATORS, loop->latch, bb)) |
| break; |
| |
| /* In a loop that is always entered we may proceed anyway. |
| But record that we entered it and stop once we leave it. */ |
| inn_loop = bb->loop_father; |
| } |
| } |
| |
| while (1) |
| { |
| last->aux = loop; |
| if (last == loop->header) |
| break; |
| last = get_immediate_dominator (CDI_DOMINATORS, last); |
| } |
| |
| free (bbs); |
| } |
| |
| for (loop = loop->inner; loop; loop = loop->next) |
| fill_always_executed_in (loop, contains_call); |
| } |
| |
| /* Compute the global information needed by the loop invariant motion pass. */ |
| |
| static void |
| tree_ssa_lim_initialize (void) |
| { |
| sbitmap contains_call = sbitmap_alloc (last_basic_block); |
| gimple_stmt_iterator bsi; |
| struct loop *loop; |
| basic_block bb; |
| |
| sbitmap_zero (contains_call); |
| FOR_EACH_BB (bb) |
| { |
| for (bsi = gsi_start_bb (bb); !gsi_end_p (bsi); gsi_next (&bsi)) |
| { |
| if (nonpure_call_p (gsi_stmt (bsi))) |
| break; |
| } |
| |
| if (!gsi_end_p (bsi)) |
| SET_BIT (contains_call, bb->index); |
| } |
| |
| for (loop = current_loops->tree_root->inner; loop; loop = loop->next) |
| fill_always_executed_in (loop, contains_call); |
| |
| sbitmap_free (contains_call); |
| |
| lim_aux_data_map = pointer_map_create (); |
| } |
| |
| /* Cleans up after the invariant motion pass. */ |
| |
| static void |
| tree_ssa_lim_finalize (void) |
| { |
| basic_block bb; |
| unsigned i; |
| bitmap b; |
| htab_t h; |
| |
| FOR_EACH_BB (bb) |
| { |
| bb->aux = NULL; |
| } |
| |
| pointer_map_destroy (lim_aux_data_map); |
| |
| VEC_free (mem_ref_p, heap, memory_accesses.refs_list); |
| htab_delete (memory_accesses.refs); |
| |
| for (i = 0; VEC_iterate (bitmap, memory_accesses.refs_in_loop, i, b); i++) |
| BITMAP_FREE (b); |
| VEC_free (bitmap, heap, memory_accesses.refs_in_loop); |
| |
| for (i = 0; VEC_iterate (bitmap, memory_accesses.all_refs_in_loop, i, b); i++) |
| BITMAP_FREE (b); |
| VEC_free (bitmap, heap, memory_accesses.all_refs_in_loop); |
| |
| for (i = 0; VEC_iterate (bitmap, memory_accesses.clobbered_vops, i, b); i++) |
| BITMAP_FREE (b); |
| VEC_free (bitmap, heap, memory_accesses.clobbered_vops); |
| |
| for (i = 0; VEC_iterate (htab_t, memory_accesses.vop_ref_map, i, h); i++) |
| htab_delete (h); |
| VEC_free (htab_t, heap, memory_accesses.vop_ref_map); |
| |
| if (memory_accesses.ttae_cache) |
| pointer_map_destroy (memory_accesses.ttae_cache); |
| } |
| |
| /* Moves invariants from loops. Only "expensive" invariants are moved out -- |
| i.e. those that are likely to be win regardless of the register pressure. */ |
| |
| void |
| tree_ssa_lim (void) |
| { |
| tree_ssa_lim_initialize (); |
| |
| /* Gathers information about memory accesses in the loops. */ |
| analyze_memory_references (); |
| |
| /* For each statement determine the outermost loop in that it is |
| invariant and cost for computing the invariant. */ |
| determine_invariantness (); |
| |
| /* Execute store motion. Force the necessary invariants to be moved |
| out of the loops as well. */ |
| store_motion (); |
| |
| /* Move the expressions that are expensive enough. */ |
| move_computations (); |
| |
| tree_ssa_lim_finalize (); |
| } |