| /* Induction variable optimizations. |
| Copyright (C) 2003, 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, 59 Temple Place - Suite 330, Boston, MA |
| 02111-1307, USA. */ |
| |
| /* This pass tries to find the optimal set of induction variables for the loop. |
| It optimizes just the basic linear induction variables (although adding |
| support for other types should not be too hard). It includes the |
| optimizations commonly known as strength reduction, induction variable |
| coalescing and induction variable elimination. It does it in the |
| following steps: |
| |
| 1) The interesting uses of induction variables are found. This includes |
| |
| -- uses of induction variables in non-linear expressions |
| -- addresses of arrays |
| -- comparisons of induction variables |
| |
| 2) Candidates for the induction variables are found. This includes |
| |
| -- old induction variables |
| -- the variables defined by expressions derived from the "interesting |
| uses" above |
| |
| 3) The optimal (w.r. to a cost function) set of variables is chosen. The |
| cost function assigns a cost to sets of induction variables and consists |
| of three parts: |
| |
| -- The use costs. Each of the interesting uses chooses the best induction |
| variable in the set and adds its cost to the sum. The cost reflects |
| the time spent on modifying the induction variables value to be usable |
| for the given purpose (adding base and offset for arrays, etc.). |
| -- The variable costs. Each of the variables has a cost assigned that |
| reflects the costs associated with incrementing the value of the |
| variable. The original variables are somewhat preferred. |
| -- The set cost. Depending on the size of the set, extra cost may be |
| added to reflect register pressure. |
| |
| All the costs are defined in a machine-specific way, using the target |
| hooks and machine descriptions to determine them. |
| |
| 4) The trees are transformed to use the new variables, the dead code is |
| removed. |
| |
| All of this is done loop by loop. Doing it globally is theoretically |
| possible, it might give a better performance and it might enable us |
| to decide costs more precisely, but getting all the interactions right |
| would be complicated. */ |
| |
| #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 "varray.h" |
| #include "expr.h" |
| #include "tree-pass.h" |
| #include "ggc.h" |
| #include "insn-config.h" |
| #include "recog.h" |
| #include "hashtab.h" |
| #include "tree-chrec.h" |
| #include "tree-scalar-evolution.h" |
| #include "cfgloop.h" |
| #include "params.h" |
| #include "langhooks.h" |
| |
| /* The infinite cost. */ |
| #define INFTY 10000000 |
| |
| /* The expected number of loop iterations. TODO -- use profiling instead of |
| this. */ |
| #define AVG_LOOP_NITER(LOOP) 5 |
| |
| |
| /* Representation of the induction variable. */ |
| struct iv |
| { |
| tree base; /* Initial value of the iv. */ |
| tree base_object; /* A memory object to that the induction variable points. */ |
| tree step; /* Step of the iv (constant only). */ |
| tree ssa_name; /* The ssa name with the value. */ |
| bool biv_p; /* Is it a biv? */ |
| bool have_use_for; /* Do we already have a use for it? */ |
| unsigned use_id; /* The identifier in the use if it is the case. */ |
| }; |
| |
| /* Per-ssa version information (induction variable descriptions, etc.). */ |
| struct version_info |
| { |
| tree name; /* The ssa name. */ |
| struct iv *iv; /* Induction variable description. */ |
| bool has_nonlin_use; /* For a loop-level invariant, whether it is used in |
| an expression that is not an induction variable. */ |
| unsigned inv_id; /* Id of an invariant. */ |
| bool preserve_biv; /* For the original biv, whether to preserve it. */ |
| }; |
| |
| /* Information attached to loop. */ |
| struct loop_data |
| { |
| unsigned regs_used; /* Number of registers used. */ |
| }; |
| |
| /* Types of uses. */ |
| enum use_type |
| { |
| USE_NONLINEAR_EXPR, /* Use in a nonlinear expression. */ |
| USE_OUTER, /* The induction variable is used outside the loop. */ |
| USE_ADDRESS, /* Use in an address. */ |
| USE_COMPARE /* Use is a compare. */ |
| }; |
| |
| /* The candidate - cost pair. */ |
| struct cost_pair |
| { |
| struct iv_cand *cand; /* The candidate. */ |
| unsigned cost; /* The cost. */ |
| bitmap depends_on; /* The list of invariants that have to be |
| preserved. */ |
| }; |
| |
| /* Use. */ |
| struct iv_use |
| { |
| unsigned id; /* The id of the use. */ |
| enum use_type type; /* Type of the use. */ |
| struct iv *iv; /* The induction variable it is based on. */ |
| tree stmt; /* Statement in that it occurs. */ |
| tree *op_p; /* The place where it occurs. */ |
| bitmap related_cands; /* The set of "related" iv candidates, plus the common |
| important ones. */ |
| |
| unsigned n_map_members; /* Number of candidates in the cost_map list. */ |
| struct cost_pair *cost_map; |
| /* The costs wrto the iv candidates. */ |
| |
| struct iv_cand *selected; |
| /* The selected candidate. */ |
| }; |
| |
| /* The position where the iv is computed. */ |
| enum iv_position |
| { |
| IP_NORMAL, /* At the end, just before the exit condition. */ |
| IP_END, /* At the end of the latch block. */ |
| IP_ORIGINAL /* The original biv. */ |
| }; |
| |
| /* The induction variable candidate. */ |
| struct iv_cand |
| { |
| unsigned id; /* The number of the candidate. */ |
| bool important; /* Whether this is an "important" candidate, i.e. such |
| that it should be considered by all uses. */ |
| enum iv_position pos; /* Where it is computed. */ |
| tree incremented_at; /* For original biv, the statement where it is |
| incremented. */ |
| tree var_before; /* The variable used for it before increment. */ |
| tree var_after; /* The variable used for it after increment. */ |
| struct iv *iv; /* The value of the candidate. NULL for |
| "pseudocandidate" used to indicate the possibility |
| to replace the final value of an iv by direct |
| computation of the value. */ |
| unsigned cost; /* Cost of the candidate. */ |
| }; |
| |
| /* The data used by the induction variable optimizations. */ |
| |
| struct ivopts_data |
| { |
| /* The currently optimized loop. */ |
| struct loop *current_loop; |
| |
| /* Numbers of iterations for all exits of the current loop. */ |
| htab_t niters; |
| |
| /* The size of version_info array allocated. */ |
| unsigned version_info_size; |
| |
| /* The array of information for the ssa names. */ |
| struct version_info *version_info; |
| |
| /* The bitmap of indices in version_info whose value was changed. */ |
| bitmap relevant; |
| |
| /* The maximum invariant id. */ |
| unsigned max_inv_id; |
| |
| /* The uses of induction variables. */ |
| varray_type iv_uses; |
| |
| /* The candidates. */ |
| varray_type iv_candidates; |
| |
| /* A bitmap of important candidates. */ |
| bitmap important_candidates; |
| |
| /* Whether to consider just related and important candidates when replacing a |
| use. */ |
| bool consider_all_candidates; |
| }; |
| |
| /* An assignment of iv candidates to uses. */ |
| |
| struct iv_ca |
| { |
| /* The number of uses covered by the assignment. */ |
| unsigned upto; |
| |
| /* Number of uses that cannot be expressed by the candidates in the set. */ |
| unsigned bad_uses; |
| |
| /* Candidate assigned to a use, together with the related costs. */ |
| struct cost_pair **cand_for_use; |
| |
| /* Number of times each candidate is used. */ |
| unsigned *n_cand_uses; |
| |
| /* The candidates used. */ |
| bitmap cands; |
| |
| /* The number of candidates in the set. */ |
| unsigned n_cands; |
| |
| /* Total number of registers needed. */ |
| unsigned n_regs; |
| |
| /* Total cost of expressing uses. */ |
| unsigned cand_use_cost; |
| |
| /* Total cost of candidates. */ |
| unsigned cand_cost; |
| |
| /* Number of times each invariant is used. */ |
| unsigned *n_invariant_uses; |
| |
| /* Total cost of the assignment. */ |
| unsigned cost; |
| }; |
| |
| /* Difference of two iv candidate assignments. */ |
| |
| struct iv_ca_delta |
| { |
| /* Changed use. */ |
| struct iv_use *use; |
| |
| /* An old assignment (for rollback purposes). */ |
| struct cost_pair *old_cp; |
| |
| /* A new assignment. */ |
| struct cost_pair *new_cp; |
| |
| /* Next change in the list. */ |
| struct iv_ca_delta *next_change; |
| }; |
| |
| /* Bound on number of candidates below that all candidates are considered. */ |
| |
| #define CONSIDER_ALL_CANDIDATES_BOUND \ |
| ((unsigned) PARAM_VALUE (PARAM_IV_CONSIDER_ALL_CANDIDATES_BOUND)) |
| |
| /* If there are more iv occurrences, we just give up (it is quite unlikely that |
| optimizing such a loop would help, and it would take ages). */ |
| |
| #define MAX_CONSIDERED_USES \ |
| ((unsigned) PARAM_VALUE (PARAM_IV_MAX_CONSIDERED_USES)) |
| |
| /* If there are at most this number of ivs in the set, try removing unnecessary |
| ivs from the set always. */ |
| |
| #define ALWAYS_PRUNE_CAND_SET_BOUND \ |
| ((unsigned) PARAM_VALUE (PARAM_IV_ALWAYS_PRUNE_CAND_SET_BOUND)) |
| |
| /* The list of trees for that the decl_rtl field must be reset is stored |
| here. */ |
| |
| static varray_type decl_rtl_to_reset; |
| |
| /* Number of uses recorded in DATA. */ |
| |
| static inline unsigned |
| n_iv_uses (struct ivopts_data *data) |
| { |
| return VARRAY_ACTIVE_SIZE (data->iv_uses); |
| } |
| |
| /* Ith use recorded in DATA. */ |
| |
| static inline struct iv_use * |
| iv_use (struct ivopts_data *data, unsigned i) |
| { |
| return VARRAY_GENERIC_PTR_NOGC (data->iv_uses, i); |
| } |
| |
| /* Number of candidates recorded in DATA. */ |
| |
| static inline unsigned |
| n_iv_cands (struct ivopts_data *data) |
| { |
| return VARRAY_ACTIVE_SIZE (data->iv_candidates); |
| } |
| |
| /* Ith candidate recorded in DATA. */ |
| |
| static inline struct iv_cand * |
| iv_cand (struct ivopts_data *data, unsigned i) |
| { |
| return VARRAY_GENERIC_PTR_NOGC (data->iv_candidates, i); |
| } |
| |
| /* The data for LOOP. */ |
| |
| static inline struct loop_data * |
| loop_data (struct loop *loop) |
| { |
| return loop->aux; |
| } |
| |
| /* The single loop exit if it dominates the latch, NULL otherwise. */ |
| |
| static edge |
| single_dom_exit (struct loop *loop) |
| { |
| edge exit = loop->single_exit; |
| |
| if (!exit) |
| return NULL; |
| |
| if (!just_once_each_iteration_p (loop, exit->src)) |
| return NULL; |
| |
| return exit; |
| } |
| |
| /* Dumps information about the induction variable IV to FILE. */ |
| |
| extern void dump_iv (FILE *, struct iv *); |
| void |
| dump_iv (FILE *file, struct iv *iv) |
| { |
| if (iv->ssa_name) |
| { |
| fprintf (file, "ssa name "); |
| print_generic_expr (file, iv->ssa_name, TDF_SLIM); |
| fprintf (file, "\n"); |
| } |
| |
| fprintf (file, " type "); |
| print_generic_expr (file, TREE_TYPE (iv->base), TDF_SLIM); |
| fprintf (file, "\n"); |
| |
| if (iv->step) |
| { |
| fprintf (file, " base "); |
| print_generic_expr (file, iv->base, TDF_SLIM); |
| fprintf (file, "\n"); |
| |
| fprintf (file, " step "); |
| print_generic_expr (file, iv->step, TDF_SLIM); |
| fprintf (file, "\n"); |
| } |
| else |
| { |
| fprintf (file, " invariant "); |
| print_generic_expr (file, iv->base, TDF_SLIM); |
| fprintf (file, "\n"); |
| } |
| |
| if (iv->base_object) |
| { |
| fprintf (file, " base object "); |
| print_generic_expr (file, iv->base_object, TDF_SLIM); |
| fprintf (file, "\n"); |
| } |
| |
| if (iv->biv_p) |
| fprintf (file, " is a biv\n"); |
| } |
| |
| /* Dumps information about the USE to FILE. */ |
| |
| extern void dump_use (FILE *, struct iv_use *); |
| void |
| dump_use (FILE *file, struct iv_use *use) |
| { |
| fprintf (file, "use %d\n", use->id); |
| |
| switch (use->type) |
| { |
| case USE_NONLINEAR_EXPR: |
| fprintf (file, " generic\n"); |
| break; |
| |
| case USE_OUTER: |
| fprintf (file, " outside\n"); |
| break; |
| |
| case USE_ADDRESS: |
| fprintf (file, " address\n"); |
| break; |
| |
| case USE_COMPARE: |
| fprintf (file, " compare\n"); |
| break; |
| |
| default: |
| gcc_unreachable (); |
| } |
| |
| fprintf (file, " in statement "); |
| print_generic_expr (file, use->stmt, TDF_SLIM); |
| fprintf (file, "\n"); |
| |
| fprintf (file, " at position "); |
| if (use->op_p) |
| print_generic_expr (file, *use->op_p, TDF_SLIM); |
| fprintf (file, "\n"); |
| |
| dump_iv (file, use->iv); |
| |
| if (use->related_cands) |
| { |
| fprintf (file, " related candidates "); |
| dump_bitmap (file, use->related_cands); |
| } |
| } |
| |
| /* Dumps information about the uses to FILE. */ |
| |
| extern void dump_uses (FILE *, struct ivopts_data *); |
| void |
| dump_uses (FILE *file, struct ivopts_data *data) |
| { |
| unsigned i; |
| struct iv_use *use; |
| |
| for (i = 0; i < n_iv_uses (data); i++) |
| { |
| use = iv_use (data, i); |
| |
| dump_use (file, use); |
| fprintf (file, "\n"); |
| } |
| } |
| |
| /* Dumps information about induction variable candidate CAND to FILE. */ |
| |
| extern void dump_cand (FILE *, struct iv_cand *); |
| void |
| dump_cand (FILE *file, struct iv_cand *cand) |
| { |
| struct iv *iv = cand->iv; |
| |
| fprintf (file, "candidate %d%s\n", |
| cand->id, cand->important ? " (important)" : ""); |
| |
| if (!iv) |
| { |
| fprintf (file, " final value replacement\n"); |
| return; |
| } |
| |
| switch (cand->pos) |
| { |
| case IP_NORMAL: |
| fprintf (file, " incremented before exit test\n"); |
| break; |
| |
| case IP_END: |
| fprintf (file, " incremented at end\n"); |
| break; |
| |
| case IP_ORIGINAL: |
| fprintf (file, " original biv\n"); |
| break; |
| } |
| |
| dump_iv (file, iv); |
| } |
| |
| /* Returns the info for ssa version VER. */ |
| |
| static inline struct version_info * |
| ver_info (struct ivopts_data *data, unsigned ver) |
| { |
| return data->version_info + ver; |
| } |
| |
| /* Returns the info for ssa name NAME. */ |
| |
| static inline struct version_info * |
| name_info (struct ivopts_data *data, tree name) |
| { |
| return ver_info (data, SSA_NAME_VERSION (name)); |
| } |
| |
| /* Checks whether there exists number X such that X * B = A, counting modulo |
| 2^BITS. */ |
| |
| static bool |
| divide (unsigned bits, unsigned HOST_WIDE_INT a, unsigned HOST_WIDE_INT b, |
| HOST_WIDE_INT *x) |
| { |
| unsigned HOST_WIDE_INT mask = ~(~(unsigned HOST_WIDE_INT) 0 << (bits - 1) << 1); |
| unsigned HOST_WIDE_INT inv, ex, val; |
| unsigned i; |
| |
| a &= mask; |
| b &= mask; |
| |
| /* First divide the whole equation by 2 as long as possible. */ |
| while (!(a & 1) && !(b & 1)) |
| { |
| a >>= 1; |
| b >>= 1; |
| bits--; |
| mask >>= 1; |
| } |
| |
| if (!(b & 1)) |
| { |
| /* If b is still even, a is odd and there is no such x. */ |
| return false; |
| } |
| |
| /* Find the inverse of b. We compute it as |
| b^(2^(bits - 1) - 1) (mod 2^bits). */ |
| inv = 1; |
| ex = b; |
| for (i = 0; i < bits - 1; i++) |
| { |
| inv = (inv * ex) & mask; |
| ex = (ex * ex) & mask; |
| } |
| |
| val = (a * inv) & mask; |
| |
| gcc_assert (((val * b) & mask) == a); |
| |
| if ((val >> (bits - 1)) & 1) |
| val |= ~mask; |
| |
| *x = val; |
| |
| return true; |
| } |
| |
| /* Returns true if STMT is after the place where the IP_NORMAL ivs will be |
| emitted in LOOP. */ |
| |
| static bool |
| stmt_after_ip_normal_pos (struct loop *loop, tree stmt) |
| { |
| basic_block bb = ip_normal_pos (loop), sbb = bb_for_stmt (stmt); |
| |
| gcc_assert (bb); |
| |
| if (sbb == loop->latch) |
| return true; |
| |
| if (sbb != bb) |
| return false; |
| |
| return stmt == last_stmt (bb); |
| } |
| |
| /* Returns true if STMT if after the place where the original induction |
| variable CAND is incremented. */ |
| |
| static bool |
| stmt_after_ip_original_pos (struct iv_cand *cand, tree stmt) |
| { |
| basic_block cand_bb = bb_for_stmt (cand->incremented_at); |
| basic_block stmt_bb = bb_for_stmt (stmt); |
| block_stmt_iterator bsi; |
| |
| if (!dominated_by_p (CDI_DOMINATORS, stmt_bb, cand_bb)) |
| return false; |
| |
| if (stmt_bb != cand_bb) |
| return true; |
| |
| /* Scan the block from the end, since the original ivs are usually |
| incremented at the end of the loop body. */ |
| for (bsi = bsi_last (stmt_bb); ; bsi_prev (&bsi)) |
| { |
| if (bsi_stmt (bsi) == cand->incremented_at) |
| return false; |
| if (bsi_stmt (bsi) == stmt) |
| return true; |
| } |
| } |
| |
| /* Returns true if STMT if after the place where the induction variable |
| CAND is incremented in LOOP. */ |
| |
| static bool |
| stmt_after_increment (struct loop *loop, struct iv_cand *cand, tree stmt) |
| { |
| switch (cand->pos) |
| { |
| case IP_END: |
| return false; |
| |
| case IP_NORMAL: |
| return stmt_after_ip_normal_pos (loop, stmt); |
| |
| case IP_ORIGINAL: |
| return stmt_after_ip_original_pos (cand, stmt); |
| |
| default: |
| gcc_unreachable (); |
| } |
| } |
| |
| /* Element of the table in that we cache the numbers of iterations obtained |
| from exits of the loop. */ |
| |
| struct nfe_cache_elt |
| { |
| /* The edge for that the number of iterations is cached. */ |
| edge exit; |
| |
| /* True if the # of iterations was successfully determined. */ |
| bool valid_p; |
| |
| /* Description of # of iterations. */ |
| struct tree_niter_desc niter; |
| }; |
| |
| /* Hash function for nfe_cache_elt E. */ |
| |
| static hashval_t |
| nfe_hash (const void *e) |
| { |
| const struct nfe_cache_elt *elt = e; |
| |
| return htab_hash_pointer (elt->exit); |
| } |
| |
| /* Equality function for nfe_cache_elt E1 and edge E2. */ |
| |
| static int |
| nfe_eq (const void *e1, const void *e2) |
| { |
| const struct nfe_cache_elt *elt1 = e1; |
| |
| return elt1->exit == e2; |
| } |
| |
| /* Returns structure describing number of iterations determined from |
| EXIT of DATA->current_loop, or NULL if something goes wrong. */ |
| |
| static struct tree_niter_desc * |
| niter_for_exit (struct ivopts_data *data, edge exit) |
| { |
| struct nfe_cache_elt *nfe_desc; |
| PTR *slot; |
| |
| slot = htab_find_slot_with_hash (data->niters, exit, |
| htab_hash_pointer (exit), |
| INSERT); |
| |
| if (!*slot) |
| { |
| nfe_desc = xmalloc (sizeof (struct nfe_cache_elt)); |
| nfe_desc->exit = exit; |
| nfe_desc->valid_p = number_of_iterations_exit (data->current_loop, |
| exit, &nfe_desc->niter); |
| *slot = nfe_desc; |
| } |
| else |
| nfe_desc = *slot; |
| |
| if (!nfe_desc->valid_p) |
| return NULL; |
| |
| return &nfe_desc->niter; |
| } |
| |
| /* Returns structure describing number of iterations determined from |
| single dominating exit of DATA->current_loop, or NULL if something |
| goes wrong. */ |
| |
| static struct tree_niter_desc * |
| niter_for_single_dom_exit (struct ivopts_data *data) |
| { |
| edge exit = single_dom_exit (data->current_loop); |
| |
| if (!exit) |
| return NULL; |
| |
| return niter_for_exit (data, exit); |
| } |
| |
| /* Initializes data structures used by the iv optimization pass, stored |
| in DATA. LOOPS is the loop tree. */ |
| |
| static void |
| tree_ssa_iv_optimize_init (struct loops *loops, struct ivopts_data *data) |
| { |
| unsigned i; |
| |
| data->version_info_size = 2 * num_ssa_names; |
| data->version_info = xcalloc (data->version_info_size, |
| sizeof (struct version_info)); |
| data->relevant = BITMAP_ALLOC (NULL); |
| data->important_candidates = BITMAP_ALLOC (NULL); |
| data->max_inv_id = 0; |
| data->niters = htab_create (10, nfe_hash, nfe_eq, free); |
| |
| for (i = 1; i < loops->num; i++) |
| if (loops->parray[i]) |
| loops->parray[i]->aux = xcalloc (1, sizeof (struct loop_data)); |
| |
| VARRAY_GENERIC_PTR_NOGC_INIT (data->iv_uses, 20, "iv_uses"); |
| VARRAY_GENERIC_PTR_NOGC_INIT (data->iv_candidates, 20, "iv_candidates"); |
| VARRAY_GENERIC_PTR_NOGC_INIT (decl_rtl_to_reset, 20, "decl_rtl_to_reset"); |
| } |
| |
| /* Returns a memory object to that EXPR points. In case we are able to |
| determine that it does not point to any such object, NULL is returned. */ |
| |
| static tree |
| determine_base_object (tree expr) |
| { |
| enum tree_code code = TREE_CODE (expr); |
| tree base, obj, op0, op1; |
| |
| if (!POINTER_TYPE_P (TREE_TYPE (expr))) |
| return NULL_TREE; |
| |
| switch (code) |
| { |
| case INTEGER_CST: |
| return NULL_TREE; |
| |
| case ADDR_EXPR: |
| obj = TREE_OPERAND (expr, 0); |
| base = get_base_address (obj); |
| |
| if (!base) |
| return expr; |
| |
| if (TREE_CODE (base) == INDIRECT_REF) |
| return determine_base_object (TREE_OPERAND (base, 0)); |
| |
| return fold (build1 (ADDR_EXPR, ptr_type_node, base)); |
| |
| case PLUS_EXPR: |
| case MINUS_EXPR: |
| op0 = determine_base_object (TREE_OPERAND (expr, 0)); |
| op1 = determine_base_object (TREE_OPERAND (expr, 1)); |
| |
| if (!op1) |
| return op0; |
| |
| if (!op0) |
| return (code == PLUS_EXPR |
| ? op1 |
| : fold (build1 (NEGATE_EXPR, ptr_type_node, op1))); |
| |
| return fold (build (code, ptr_type_node, op0, op1)); |
| |
| case NOP_EXPR: |
| case CONVERT_EXPR: |
| return determine_base_object (TREE_OPERAND (expr, 0)); |
| |
| default: |
| return fold_convert (ptr_type_node, expr); |
| } |
| } |
| |
| /* Allocates an induction variable with given initial value BASE and step STEP |
| for loop LOOP. */ |
| |
| static struct iv * |
| alloc_iv (tree base, tree step) |
| { |
| struct iv *iv = xcalloc (1, sizeof (struct iv)); |
| |
| if (step && integer_zerop (step)) |
| step = NULL_TREE; |
| |
| iv->base = base; |
| iv->base_object = determine_base_object (base); |
| iv->step = step; |
| iv->biv_p = false; |
| iv->have_use_for = false; |
| iv->use_id = 0; |
| iv->ssa_name = NULL_TREE; |
| |
| return iv; |
| } |
| |
| /* Sets STEP and BASE for induction variable IV. */ |
| |
| static void |
| set_iv (struct ivopts_data *data, tree iv, tree base, tree step) |
| { |
| struct version_info *info = name_info (data, iv); |
| |
| gcc_assert (!info->iv); |
| |
| bitmap_set_bit (data->relevant, SSA_NAME_VERSION (iv)); |
| info->iv = alloc_iv (base, step); |
| info->iv->ssa_name = iv; |
| } |
| |
| /* Finds induction variable declaration for VAR. */ |
| |
| static struct iv * |
| get_iv (struct ivopts_data *data, tree var) |
| { |
| basic_block bb; |
| |
| if (!name_info (data, var)->iv) |
| { |
| bb = bb_for_stmt (SSA_NAME_DEF_STMT (var)); |
| |
| if (!bb |
| || !flow_bb_inside_loop_p (data->current_loop, bb)) |
| set_iv (data, var, var, NULL_TREE); |
| } |
| |
| return name_info (data, var)->iv; |
| } |
| |
| /* Determines the step of a biv defined in PHI. */ |
| |
| static tree |
| determine_biv_step (tree phi) |
| { |
| struct loop *loop = bb_for_stmt (phi)->loop_father; |
| tree name = PHI_RESULT (phi), base, step; |
| tree type = TREE_TYPE (name); |
| |
| if (!is_gimple_reg (name)) |
| return NULL_TREE; |
| |
| if (!simple_iv (loop, phi, name, &base, &step)) |
| return NULL_TREE; |
| |
| if (!step) |
| return build_int_cst (type, 0); |
| |
| return step; |
| } |
| |
| /* Returns true if EXP is a ssa name that occurs in an abnormal phi node. */ |
| |
| static bool |
| abnormal_ssa_name_p (tree exp) |
| { |
| if (!exp) |
| return false; |
| |
| if (TREE_CODE (exp) != SSA_NAME) |
| return false; |
| |
| return SSA_NAME_OCCURS_IN_ABNORMAL_PHI (exp) != 0; |
| } |
| |
| /* Returns false if BASE or INDEX contains a ssa name that occurs in an |
| abnormal phi node. Callback for for_each_index. */ |
| |
| static bool |
| idx_contains_abnormal_ssa_name_p (tree base, tree *index, |
| void *data ATTRIBUTE_UNUSED) |
| { |
| if (TREE_CODE (base) == ARRAY_REF) |
| { |
| if (abnormal_ssa_name_p (TREE_OPERAND (base, 2))) |
| return false; |
| if (abnormal_ssa_name_p (TREE_OPERAND (base, 3))) |
| return false; |
| } |
| |
| return !abnormal_ssa_name_p (*index); |
| } |
| |
| /* Returns true if EXPR contains a ssa name that occurs in an |
| abnormal phi node. */ |
| |
| static bool |
| contains_abnormal_ssa_name_p (tree expr) |
| { |
| enum tree_code code = TREE_CODE (expr); |
| enum tree_code_class class = TREE_CODE_CLASS (code); |
| |
| if (code == SSA_NAME) |
| return SSA_NAME_OCCURS_IN_ABNORMAL_PHI (expr) != 0; |
| |
| if (code == INTEGER_CST |
| || is_gimple_min_invariant (expr)) |
| return false; |
| |
| if (code == ADDR_EXPR) |
| return !for_each_index (&TREE_OPERAND (expr, 0), |
| idx_contains_abnormal_ssa_name_p, |
| NULL); |
| |
| switch (class) |
| { |
| case tcc_binary: |
| case tcc_comparison: |
| if (contains_abnormal_ssa_name_p (TREE_OPERAND (expr, 1))) |
| return true; |
| |
| /* Fallthru. */ |
| case tcc_unary: |
| if (contains_abnormal_ssa_name_p (TREE_OPERAND (expr, 0))) |
| return true; |
| |
| break; |
| |
| default: |
| gcc_unreachable (); |
| } |
| |
| return false; |
| } |
| |
| /* Finds basic ivs. */ |
| |
| static bool |
| find_bivs (struct ivopts_data *data) |
| { |
| tree phi, step, type, base; |
| bool found = false; |
| struct loop *loop = data->current_loop; |
| |
| for (phi = phi_nodes (loop->header); phi; phi = PHI_CHAIN (phi)) |
| { |
| if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (PHI_RESULT (phi))) |
| continue; |
| |
| step = determine_biv_step (phi); |
| |
| if (!step) |
| continue; |
| if (cst_and_fits_in_hwi (step) |
| && int_cst_value (step) == 0) |
| continue; |
| |
| base = PHI_ARG_DEF_FROM_EDGE (phi, loop_preheader_edge (loop)); |
| if (contains_abnormal_ssa_name_p (base)) |
| continue; |
| |
| type = TREE_TYPE (PHI_RESULT (phi)); |
| base = fold_convert (type, base); |
| step = fold_convert (type, step); |
| |
| /* FIXME: We do not handle induction variables whose step does |
| not satisfy cst_and_fits_in_hwi. */ |
| if (!cst_and_fits_in_hwi (step)) |
| continue; |
| |
| set_iv (data, PHI_RESULT (phi), base, step); |
| found = true; |
| } |
| |
| return found; |
| } |
| |
| /* Marks basic ivs. */ |
| |
| static void |
| mark_bivs (struct ivopts_data *data) |
| { |
| tree phi, var; |
| struct iv *iv, *incr_iv; |
| struct loop *loop = data->current_loop; |
| basic_block incr_bb; |
| |
| for (phi = phi_nodes (loop->header); phi; phi = PHI_CHAIN (phi)) |
| { |
| iv = get_iv (data, PHI_RESULT (phi)); |
| if (!iv) |
| continue; |
| |
| var = PHI_ARG_DEF_FROM_EDGE (phi, loop_latch_edge (loop)); |
| incr_iv = get_iv (data, var); |
| if (!incr_iv) |
| continue; |
| |
| /* If the increment is in the subloop, ignore it. */ |
| incr_bb = bb_for_stmt (SSA_NAME_DEF_STMT (var)); |
| if (incr_bb->loop_father != data->current_loop |
| || (incr_bb->flags & BB_IRREDUCIBLE_LOOP)) |
| continue; |
| |
| iv->biv_p = true; |
| incr_iv->biv_p = true; |
| } |
| } |
| |
| /* Checks whether STMT defines a linear induction variable and stores its |
| parameters to BASE and STEP. */ |
| |
| static bool |
| find_givs_in_stmt_scev (struct ivopts_data *data, tree stmt, |
| tree *base, tree *step) |
| { |
| tree lhs; |
| struct loop *loop = data->current_loop; |
| |
| *base = NULL_TREE; |
| *step = NULL_TREE; |
| |
| if (TREE_CODE (stmt) != MODIFY_EXPR) |
| return false; |
| |
| lhs = TREE_OPERAND (stmt, 0); |
| if (TREE_CODE (lhs) != SSA_NAME) |
| return false; |
| |
| if (!simple_iv (loop, stmt, TREE_OPERAND (stmt, 1), base, step)) |
| return false; |
| |
| /* FIXME: We do not handle induction variables whose step does |
| not satisfy cst_and_fits_in_hwi. */ |
| if (!zero_p (*step) |
| && !cst_and_fits_in_hwi (*step)) |
| return false; |
| |
| if (contains_abnormal_ssa_name_p (*base)) |
| return false; |
| |
| return true; |
| } |
| |
| /* Finds general ivs in statement STMT. */ |
| |
| static void |
| find_givs_in_stmt (struct ivopts_data *data, tree stmt) |
| { |
| tree base, step; |
| |
| if (!find_givs_in_stmt_scev (data, stmt, &base, &step)) |
| return; |
| |
| set_iv (data, TREE_OPERAND (stmt, 0), base, step); |
| } |
| |
| /* Finds general ivs in basic block BB. */ |
| |
| static void |
| find_givs_in_bb (struct ivopts_data *data, basic_block bb) |
| { |
| block_stmt_iterator bsi; |
| |
| for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi)) |
| find_givs_in_stmt (data, bsi_stmt (bsi)); |
| } |
| |
| /* Finds general ivs. */ |
| |
| static void |
| find_givs (struct ivopts_data *data) |
| { |
| struct loop *loop = data->current_loop; |
| basic_block *body = get_loop_body_in_dom_order (loop); |
| unsigned i; |
| |
| for (i = 0; i < loop->num_nodes; i++) |
| find_givs_in_bb (data, body[i]); |
| free (body); |
| } |
| |
| /* For each ssa name defined in LOOP determines whether it is an induction |
| variable and if so, its initial value and step. */ |
| |
| static bool |
| find_induction_variables (struct ivopts_data *data) |
| { |
| unsigned i; |
| bitmap_iterator bi; |
| |
| if (!find_bivs (data)) |
| return false; |
| |
| find_givs (data); |
| mark_bivs (data); |
| |
| if (dump_file && (dump_flags & TDF_DETAILS)) |
| { |
| struct tree_niter_desc *niter; |
| |
| niter = niter_for_single_dom_exit (data); |
| |
| if (niter) |
| { |
| fprintf (dump_file, " number of iterations "); |
| print_generic_expr (dump_file, niter->niter, TDF_SLIM); |
| fprintf (dump_file, "\n"); |
| |
| fprintf (dump_file, " may be zero if "); |
| print_generic_expr (dump_file, niter->may_be_zero, TDF_SLIM); |
| fprintf (dump_file, "\n"); |
| fprintf (dump_file, "\n"); |
| }; |
| |
| fprintf (dump_file, "Induction variables:\n\n"); |
| |
| EXECUTE_IF_SET_IN_BITMAP (data->relevant, 0, i, bi) |
| { |
| if (ver_info (data, i)->iv) |
| dump_iv (dump_file, ver_info (data, i)->iv); |
| } |
| } |
| |
| return true; |
| } |
| |
| /* Records a use of type USE_TYPE at *USE_P in STMT whose value is IV. */ |
| |
| static struct iv_use * |
| record_use (struct ivopts_data *data, tree *use_p, struct iv *iv, |
| tree stmt, enum use_type use_type) |
| { |
| struct iv_use *use = xcalloc (1, sizeof (struct iv_use)); |
| |
| use->id = n_iv_uses (data); |
| use->type = use_type; |
| use->iv = iv; |
| use->stmt = stmt; |
| use->op_p = use_p; |
| use->related_cands = BITMAP_ALLOC (NULL); |
| |
| /* To avoid showing ssa name in the dumps, if it was not reset by the |
| caller. */ |
| iv->ssa_name = NULL_TREE; |
| |
| if (dump_file && (dump_flags & TDF_DETAILS)) |
| dump_use (dump_file, use); |
| |
| VARRAY_PUSH_GENERIC_PTR_NOGC (data->iv_uses, use); |
| |
| return use; |
| } |
| |
| /* Checks whether OP is a loop-level invariant and if so, records it. |
| NONLINEAR_USE is true if the invariant is used in a way we do not |
| handle specially. */ |
| |
| static void |
| record_invariant (struct ivopts_data *data, tree op, bool nonlinear_use) |
| { |
| basic_block bb; |
| struct version_info *info; |
| |
| if (TREE_CODE (op) != SSA_NAME |
| || !is_gimple_reg (op)) |
| return; |
| |
| bb = bb_for_stmt (SSA_NAME_DEF_STMT (op)); |
| if (bb |
| && flow_bb_inside_loop_p (data->current_loop, bb)) |
| return; |
| |
| info = name_info (data, op); |
| info->name = op; |
| info->has_nonlin_use |= nonlinear_use; |
| if (!info->inv_id) |
| info->inv_id = ++data->max_inv_id; |
| bitmap_set_bit (data->relevant, SSA_NAME_VERSION (op)); |
| } |
| |
| /* Checks whether the use OP is interesting and if so, records it |
| as TYPE. */ |
| |
| static struct iv_use * |
| find_interesting_uses_outer_or_nonlin (struct ivopts_data *data, tree op, |
| enum use_type type) |
| { |
| struct iv *iv; |
| struct iv *civ; |
| tree stmt; |
| struct iv_use *use; |
| |
| if (TREE_CODE (op) != SSA_NAME) |
| return NULL; |
| |
| iv = get_iv (data, op); |
| if (!iv) |
| return NULL; |
| |
| if (iv->have_use_for) |
| { |
| use = iv_use (data, iv->use_id); |
| |
| gcc_assert (use->type == USE_NONLINEAR_EXPR |
| || use->type == USE_OUTER); |
| |
| if (type == USE_NONLINEAR_EXPR) |
| use->type = USE_NONLINEAR_EXPR; |
| return use; |
| } |
| |
| if (zero_p (iv->step)) |
| { |
| record_invariant (data, op, true); |
| return NULL; |
| } |
| iv->have_use_for = true; |
| |
| civ = xmalloc (sizeof (struct iv)); |
| *civ = *iv; |
| |
| stmt = SSA_NAME_DEF_STMT (op); |
| gcc_assert (TREE_CODE (stmt) == PHI_NODE |
| || TREE_CODE (stmt) == MODIFY_EXPR); |
| |
| use = record_use (data, NULL, civ, stmt, type); |
| iv->use_id = use->id; |
| |
| return use; |
| } |
| |
| /* Checks whether the use OP is interesting and if so, records it. */ |
| |
| static struct iv_use * |
| find_interesting_uses_op (struct ivopts_data *data, tree op) |
| { |
| return find_interesting_uses_outer_or_nonlin (data, op, USE_NONLINEAR_EXPR); |
| } |
| |
| /* Records a definition of induction variable OP that is used outside of the |
| loop. */ |
| |
| static struct iv_use * |
| find_interesting_uses_outer (struct ivopts_data *data, tree op) |
| { |
| return find_interesting_uses_outer_or_nonlin (data, op, USE_OUTER); |
| } |
| |
| /* Checks whether the condition *COND_P in STMT is interesting |
| and if so, records it. */ |
| |
| static void |
| find_interesting_uses_cond (struct ivopts_data *data, tree stmt, tree *cond_p) |
| { |
| tree *op0_p; |
| tree *op1_p; |
| struct iv *iv0 = NULL, *iv1 = NULL, *civ; |
| struct iv const_iv; |
| tree zero = integer_zero_node; |
| |
| const_iv.step = NULL_TREE; |
| |
| if (integer_zerop (*cond_p) |
| || integer_nonzerop (*cond_p)) |
| return; |
| |
| if (TREE_CODE (*cond_p) == SSA_NAME) |
| { |
| op0_p = cond_p; |
| op1_p = &zero; |
| } |
| else |
| { |
| op0_p = &TREE_OPERAND (*cond_p, 0); |
| op1_p = &TREE_OPERAND (*cond_p, 1); |
| } |
| |
| if (TREE_CODE (*op0_p) == SSA_NAME) |
| iv0 = get_iv (data, *op0_p); |
| else |
| iv0 = &const_iv; |
| |
| if (TREE_CODE (*op1_p) == SSA_NAME) |
| iv1 = get_iv (data, *op1_p); |
| else |
| iv1 = &const_iv; |
| |
| if (/* When comparing with non-invariant value, we may not do any senseful |
| induction variable elimination. */ |
| (!iv0 || !iv1) |
| /* Eliminating condition based on two ivs would be nontrivial. |
| ??? TODO -- it is not really important to handle this case. */ |
| || (!zero_p (iv0->step) && !zero_p (iv1->step))) |
| { |
| find_interesting_uses_op (data, *op0_p); |
| find_interesting_uses_op (data, *op1_p); |
| return; |
| } |
| |
| if (zero_p (iv0->step) && zero_p (iv1->step)) |
| { |
| /* If both are invariants, this is a work for unswitching. */ |
| return; |
| } |
| |
| civ = xmalloc (sizeof (struct iv)); |
| *civ = zero_p (iv0->step) ? *iv1: *iv0; |
| record_use (data, cond_p, civ, stmt, USE_COMPARE); |
| } |
| |
| /* Returns true if expression EXPR is obviously invariant in LOOP, |
| i.e. if all its operands are defined outside of the LOOP. */ |
| |
| bool |
| expr_invariant_in_loop_p (struct loop *loop, tree expr) |
| { |
| basic_block def_bb; |
| unsigned i, len; |
| |
| if (is_gimple_min_invariant (expr)) |
| return true; |
| |
| if (TREE_CODE (expr) == SSA_NAME) |
| { |
| def_bb = bb_for_stmt (SSA_NAME_DEF_STMT (expr)); |
| if (def_bb |
| && flow_bb_inside_loop_p (loop, def_bb)) |
| return false; |
| |
| return true; |
| } |
| |
| if (!EXPR_P (expr)) |
| return false; |
| |
| len = TREE_CODE_LENGTH (TREE_CODE (expr)); |
| for (i = 0; i < len; i++) |
| if (!expr_invariant_in_loop_p (loop, TREE_OPERAND (expr, i))) |
| return false; |
| |
| return true; |
| } |
| |
| /* Cumulates the steps of indices into DATA and replaces their values with the |
| initial ones. Returns false when the value of the index cannot be determined. |
| Callback for for_each_index. */ |
| |
| struct ifs_ivopts_data |
| { |
| struct ivopts_data *ivopts_data; |
| tree stmt; |
| tree *step_p; |
| }; |
| |
| static bool |
| idx_find_step (tree base, tree *idx, void *data) |
| { |
| struct ifs_ivopts_data *dta = data; |
| struct iv *iv; |
| tree step, type, iv_type, iv_step, lbound, off; |
| struct loop *loop = dta->ivopts_data->current_loop; |
| |
| if (TREE_CODE (base) == MISALIGNED_INDIRECT_REF |
| || TREE_CODE (base) == ALIGN_INDIRECT_REF) |
| return false; |
| |
| /* If base is a component ref, require that the offset of the reference |
| be invariant. */ |
| if (TREE_CODE (base) == COMPONENT_REF) |
| { |
| off = component_ref_field_offset (base); |
| return expr_invariant_in_loop_p (loop, off); |
| } |
| |
| /* If base is array, first check whether we will be able to move the |
| reference out of the loop (in order to take its address in strength |
| reduction). In order for this to work we need both lower bound |
| and step to be loop invariants. */ |
| if (TREE_CODE (base) == ARRAY_REF) |
| { |
| step = array_ref_element_size (base); |
| lbound = array_ref_low_bound (base); |
| |
| if (!expr_invariant_in_loop_p (loop, step) |
| || !expr_invariant_in_loop_p (loop, lbound)) |
| return false; |
| } |
| |
| if (TREE_CODE (*idx) != SSA_NAME) |
| return true; |
| |
| iv = get_iv (dta->ivopts_data, *idx); |
| if (!iv) |
| return false; |
| |
| *idx = iv->base; |
| |
| if (!iv->step) |
| return true; |
| |
| iv_type = TREE_TYPE (iv->base); |
| type = build_pointer_type (TREE_TYPE (base)); |
| if (TREE_CODE (base) == ARRAY_REF) |
| { |
| step = array_ref_element_size (base); |
| |
| /* We only handle addresses whose step is an integer constant. */ |
| if (TREE_CODE (step) != INTEGER_CST) |
| return false; |
| } |
| else |
| /* The step for pointer arithmetics already is 1 byte. */ |
| step = build_int_cst (type, 1); |
| |
| if (TYPE_PRECISION (iv_type) < TYPE_PRECISION (type)) |
| iv_step = can_count_iv_in_wider_type (dta->ivopts_data->current_loop, |
| type, iv->base, iv->step, dta->stmt); |
| else |
| iv_step = fold_convert (iv_type, iv->step); |
| |
| if (!iv_step) |
| { |
| /* The index might wrap. */ |
| return false; |
| } |
| |
| step = fold_binary_to_constant (MULT_EXPR, type, step, iv_step); |
| |
| if (!*dta->step_p) |
| *dta->step_p = step; |
| else |
| *dta->step_p = fold_binary_to_constant (PLUS_EXPR, type, |
| *dta->step_p, step); |
| |
| return true; |
| } |
| |
| /* Records use in index IDX. Callback for for_each_index. Ivopts data |
| object is passed to it in DATA. */ |
| |
| static bool |
| idx_record_use (tree base, tree *idx, |
| void *data) |
| { |
| find_interesting_uses_op (data, *idx); |
| if (TREE_CODE (base) == ARRAY_REF) |
| { |
| find_interesting_uses_op (data, array_ref_element_size (base)); |
| find_interesting_uses_op (data, array_ref_low_bound (base)); |
| } |
| return true; |
| } |
| |
| /* Returns true if memory reference REF may be unaligned. */ |
| |
| static bool |
| may_be_unaligned_p (tree ref) |
| { |
| tree base; |
| tree base_type; |
| HOST_WIDE_INT bitsize; |
| HOST_WIDE_INT bitpos; |
| tree toffset; |
| enum machine_mode mode; |
| int unsignedp, volatilep; |
| unsigned base_align; |
| |
| /* The test below is basically copy of what expr.c:normal_inner_ref |
| does to check whether the object must be loaded by parts when |
| STRICT_ALIGNMENT is true. */ |
| base = get_inner_reference (ref, &bitsize, &bitpos, &toffset, &mode, |
| &unsignedp, &volatilep, true); |
| base_type = TREE_TYPE (base); |
| base_align = TYPE_ALIGN (base_type); |
| |
| if (mode != BLKmode |
| && (base_align < GET_MODE_ALIGNMENT (mode) |
| || bitpos % GET_MODE_ALIGNMENT (mode) != 0 |
| || bitpos % BITS_PER_UNIT != 0)) |
| return true; |
| |
| return false; |
| } |
| |
| /* Finds addresses in *OP_P inside STMT. */ |
| |
| static void |
| find_interesting_uses_address (struct ivopts_data *data, tree stmt, tree *op_p) |
| { |
| tree base = unshare_expr (*op_p), step = NULL; |
| struct iv *civ; |
| struct ifs_ivopts_data ifs_ivopts_data; |
| |
| /* Do not play with volatile memory references. A bit too conservative, |
| perhaps, but safe. */ |
| if (stmt_ann (stmt)->has_volatile_ops) |
| goto fail; |
| |
| /* Ignore bitfields for now. Not really something terribly complicated |
| to handle. TODO. */ |
| /* APPLE LOCAL begin mainline 4516827 pr 26643 */ |
| if (TREE_CODE (base) == BIT_FIELD_REF |
| || (TREE_CODE (base) == COMPONENT_REF |
| && DECL_NONADDRESSABLE_P (TREE_OPERAND (base, 1)))) |
| goto fail; |
| /* APPLE LOCAL end mainline 4516827 pr 26643 */ |
| |
| if (STRICT_ALIGNMENT |
| && may_be_unaligned_p (base)) |
| goto fail; |
| |
| ifs_ivopts_data.ivopts_data = data; |
| ifs_ivopts_data.stmt = stmt; |
| ifs_ivopts_data.step_p = &step; |
| if (!for_each_index (&base, idx_find_step, &ifs_ivopts_data) |
| || zero_p (step)) |
| goto fail; |
| |
| gcc_assert (TREE_CODE (base) != ALIGN_INDIRECT_REF); |
| gcc_assert (TREE_CODE (base) != MISALIGNED_INDIRECT_REF); |
| |
| if (TREE_CODE (base) == INDIRECT_REF) |
| base = TREE_OPERAND (base, 0); |
| else |
| base = build_addr (base); |
| |
| civ = alloc_iv (base, step); |
| record_use (data, op_p, civ, stmt, USE_ADDRESS); |
| return; |
| |
| fail: |
| for_each_index (op_p, idx_record_use, data); |
| } |
| |
| /* Finds and records invariants used in STMT. */ |
| |
| static void |
| find_invariants_stmt (struct ivopts_data *data, tree stmt) |
| { |
| use_optype uses = NULL; |
| unsigned i, n; |
| tree op; |
| |
| if (TREE_CODE (stmt) == PHI_NODE) |
| n = PHI_NUM_ARGS (stmt); |
| else |
| { |
| get_stmt_operands (stmt); |
| uses = STMT_USE_OPS (stmt); |
| n = NUM_USES (uses); |
| } |
| |
| for (i = 0; i < n; i++) |
| { |
| if (TREE_CODE (stmt) == PHI_NODE) |
| op = PHI_ARG_DEF (stmt, i); |
| else |
| op = USE_OP (uses, i); |
| |
| record_invariant (data, op, false); |
| } |
| } |
| |
| /* Finds interesting uses of induction variables in the statement STMT. */ |
| |
| static void |
| find_interesting_uses_stmt (struct ivopts_data *data, tree stmt) |
| { |
| struct iv *iv; |
| tree op, lhs, rhs; |
| use_optype uses = NULL; |
| unsigned i, n; |
| |
| find_invariants_stmt (data, stmt); |
| |
| if (TREE_CODE (stmt) == COND_EXPR) |
| { |
| find_interesting_uses_cond (data, stmt, &COND_EXPR_COND (stmt)); |
| return; |
| } |
| |
| if (TREE_CODE (stmt) == MODIFY_EXPR) |
| { |
| lhs = TREE_OPERAND (stmt, 0); |
| rhs = TREE_OPERAND (stmt, 1); |
| |
| if (TREE_CODE (lhs) == SSA_NAME) |
| { |
| /* If the statement defines an induction variable, the uses are not |
| interesting by themselves. */ |
| |
| iv = get_iv (data, lhs); |
| |
| if (iv && !zero_p (iv->step)) |
| return; |
| } |
| |
| switch (TREE_CODE_CLASS (TREE_CODE (rhs))) |
| { |
| case tcc_comparison: |
| find_interesting_uses_cond (data, stmt, &TREE_OPERAND (stmt, 1)); |
| return; |
| |
| case tcc_reference: |
| find_interesting_uses_address (data, stmt, &TREE_OPERAND (stmt, 1)); |
| if (REFERENCE_CLASS_P (lhs)) |
| find_interesting_uses_address (data, stmt, &TREE_OPERAND (stmt, 0)); |
| return; |
| |
| default: ; |
| } |
| |
| if (REFERENCE_CLASS_P (lhs) |
| && is_gimple_val (rhs)) |
| { |
| find_interesting_uses_address (data, stmt, &TREE_OPERAND (stmt, 0)); |
| find_interesting_uses_op (data, rhs); |
| return; |
| } |
| |
| /* TODO -- we should also handle address uses of type |
| |
| memory = call (whatever); |
| |
| and |
| |
| call (memory). */ |
| } |
| |
| if (TREE_CODE (stmt) == PHI_NODE |
| && bb_for_stmt (stmt) == data->current_loop->header) |
| { |
| lhs = PHI_RESULT (stmt); |
| iv = get_iv (data, lhs); |
| |
| if (iv && !zero_p (iv->step)) |
| return; |
| } |
| |
| if (TREE_CODE (stmt) == PHI_NODE) |
| n = PHI_NUM_ARGS (stmt); |
| else |
| { |
| uses = STMT_USE_OPS (stmt); |
| n = NUM_USES (uses); |
| } |
| |
| for (i = 0; i < n; i++) |
| { |
| if (TREE_CODE (stmt) == PHI_NODE) |
| op = PHI_ARG_DEF (stmt, i); |
| else |
| op = USE_OP (uses, i); |
| |
| if (TREE_CODE (op) != SSA_NAME) |
| continue; |
| |
| iv = get_iv (data, op); |
| if (!iv) |
| continue; |
| |
| find_interesting_uses_op (data, op); |
| } |
| } |
| |
| /* Finds interesting uses of induction variables outside of loops |
| on loop exit edge EXIT. */ |
| |
| static void |
| find_interesting_uses_outside (struct ivopts_data *data, edge exit) |
| { |
| tree phi, def; |
| |
| for (phi = phi_nodes (exit->dest); phi; phi = PHI_CHAIN (phi)) |
| { |
| def = PHI_ARG_DEF_FROM_EDGE (phi, exit); |
| find_interesting_uses_outer (data, def); |
| } |
| } |
| |
| /* Finds uses of the induction variables that are interesting. */ |
| |
| static void |
| find_interesting_uses (struct ivopts_data *data) |
| { |
| basic_block bb; |
| block_stmt_iterator bsi; |
| tree phi; |
| basic_block *body = get_loop_body (data->current_loop); |
| unsigned i; |
| struct version_info *info; |
| edge e; |
| |
| if (dump_file && (dump_flags & TDF_DETAILS)) |
| fprintf (dump_file, "Uses:\n\n"); |
| |
| for (i = 0; i < data->current_loop->num_nodes; i++) |
| { |
| edge_iterator ei; |
| bb = body[i]; |
| |
| FOR_EACH_EDGE (e, ei, bb->succs) |
| if (e->dest != EXIT_BLOCK_PTR |
| && !flow_bb_inside_loop_p (data->current_loop, e->dest)) |
| find_interesting_uses_outside (data, e); |
| |
| for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi)) |
| find_interesting_uses_stmt (data, phi); |
| for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi)) |
| find_interesting_uses_stmt (data, bsi_stmt (bsi)); |
| } |
| |
| if (dump_file && (dump_flags & TDF_DETAILS)) |
| { |
| bitmap_iterator bi; |
| |
| fprintf (dump_file, "\n"); |
| |
| EXECUTE_IF_SET_IN_BITMAP (data->relevant, 0, i, bi) |
| { |
| info = ver_info (data, i); |
| if (info->inv_id) |
| { |
| fprintf (dump_file, " "); |
| print_generic_expr (dump_file, info->name, TDF_SLIM); |
| fprintf (dump_file, " is invariant (%d)%s\n", |
| info->inv_id, info->has_nonlin_use ? "" : ", eliminable"); |
| } |
| } |
| |
| fprintf (dump_file, "\n"); |
| } |
| |
| free (body); |
| } |
| |
| /* Strips constant offsets from EXPR and stores them to OFFSET. If INSIDE_ADDR |
| is true, assume we are inside an address. */ |
| |
| static tree |
| strip_offset (tree expr, bool inside_addr, unsigned HOST_WIDE_INT *offset) |
| { |
| tree op0 = NULL_TREE, op1 = NULL_TREE, step; |
| enum tree_code code; |
| tree type, orig_type = TREE_TYPE (expr); |
| unsigned HOST_WIDE_INT off0, off1, st; |
| tree orig_expr = expr; |
| |
| STRIP_NOPS (expr); |
| type = TREE_TYPE (expr); |
| code = TREE_CODE (expr); |
| *offset = 0; |
| |
| switch (code) |
| { |
| case INTEGER_CST: |
| if (!cst_and_fits_in_hwi (expr) |
| || zero_p (expr)) |
| return orig_expr; |
| |
| *offset = int_cst_value (expr); |
| return build_int_cst_type (orig_type, 0); |
| |
| case PLUS_EXPR: |
| case MINUS_EXPR: |
| op0 = TREE_OPERAND (expr, 0); |
| op1 = TREE_OPERAND (expr, 1); |
| |
| op0 = strip_offset (op0, false, &off0); |
| op1 = strip_offset (op1, false, &off1); |
| |
| *offset = (code == PLUS_EXPR ? off0 + off1 : off0 - off1); |
| if (op0 == TREE_OPERAND (expr, 0) |
| && op1 == TREE_OPERAND (expr, 1)) |
| return orig_expr; |
| |
| if (zero_p (op1)) |
| expr = op0; |
| else if (zero_p (op0)) |
| { |
| if (code == PLUS_EXPR) |
| expr = op1; |
| else |
| expr = build1 (NEGATE_EXPR, type, op1); |
| } |
| else |
| expr = build2 (code, type, op0, op1); |
| |
| return fold_convert (orig_type, expr); |
| |
| case ARRAY_REF: |
| if (!inside_addr) |
| return orig_expr; |
| |
| step = array_ref_element_size (expr); |
| if (!cst_and_fits_in_hwi (step)) |
| break; |
| |
| st = int_cst_value (step); |
| op1 = TREE_OPERAND (expr, 1); |
| op1 = strip_offset (op1, false, &off1); |
| *offset = off1 * st; |
| break; |
| |
| case COMPONENT_REF: |
| if (!inside_addr) |
| return orig_expr; |
| break; |
| |
| case ADDR_EXPR: |
| inside_addr = true; |
| break; |
| |
| default: |
| return orig_expr; |
| } |
| |
| /* Default handling of expressions for that we want to recurse into |
| the first operand. */ |
| op0 = TREE_OPERAND (expr, 0); |
| op0 = strip_offset (op0, inside_addr, &off0); |
| *offset += off0; |
| |
| if (op0 == TREE_OPERAND (expr, 0) |
| && (!op1 || op1 == TREE_OPERAND (expr, 1))) |
| return orig_expr; |
| |
| expr = copy_node (expr); |
| TREE_OPERAND (expr, 0) = op0; |
| if (op1) |
| TREE_OPERAND (expr, 1) = op1; |
| |
| return fold_convert (orig_type, expr); |
| } |
| |
| /* Returns variant of TYPE that can be used as base for different uses. |
| For integer types, we return unsigned variant of the type, which |
| avoids problems with overflows. For pointer types, we return void *. */ |
| |
| static tree |
| generic_type_for (tree type) |
| { |
| if (POINTER_TYPE_P (type)) |
| return ptr_type_node; |
| |
| if (TYPE_UNSIGNED (type)) |
| return type; |
| |
| return unsigned_type_for (type); |
| } |
| |
| /* Adds a candidate BASE + STEP * i. Important field is set to IMPORTANT and |
| position to POS. If USE is not NULL, the candidate is set as related to |
| it. If both BASE and STEP are NULL, we add a pseudocandidate for the |
| replacement of the final value of the iv by a direct computation. */ |
| |
| static struct iv_cand * |
| add_candidate_1 (struct ivopts_data *data, |
| tree base, tree step, bool important, enum iv_position pos, |
| struct iv_use *use, tree incremented_at) |
| { |
| unsigned i; |
| struct iv_cand *cand = NULL; |
| tree type, orig_type; |
| |
| if (base) |
| { |
| orig_type = TREE_TYPE (base); |
| type = generic_type_for (orig_type); |
| if (type != orig_type) |
| { |
| base = fold_convert (type, base); |
| if (step) |
| step = fold_convert (type, step); |
| } |
| } |
| |
| for (i = 0; i < n_iv_cands (data); i++) |
| { |
| cand = iv_cand (data, i); |
| |
| if (cand->pos != pos) |
| continue; |
| |
| if (cand->incremented_at != incremented_at) |
| continue; |
| |
| if (!cand->iv) |
| { |
| if (!base && !step) |
| break; |
| |
| continue; |
| } |
| |
| if (!base && !step) |
| continue; |
| |
| if (!operand_equal_p (base, cand->iv->base, 0)) |
| continue; |
| |
| if (zero_p (cand->iv->step)) |
| { |
| if (zero_p (step)) |
| break; |
| } |
| else |
| { |
| if (step && operand_equal_p (step, cand->iv->step, 0)) |
| break; |
| } |
| } |
| |
| if (i == n_iv_cands (data)) |
| { |
| cand = xcalloc (1, sizeof (struct iv_cand)); |
| cand->id = i; |
| |
| if (!base && !step) |
| cand->iv = NULL; |
| else |
| cand->iv = alloc_iv (base, step); |
| |
| cand->pos = pos; |
| if (pos != IP_ORIGINAL && cand->iv) |
| { |
| cand->var_before = create_tmp_var_raw (TREE_TYPE (base), "ivtmp"); |
| cand->var_after = cand->var_before; |
| } |
| cand->important = important; |
| cand->incremented_at = incremented_at; |
| VARRAY_PUSH_GENERIC_PTR_NOGC (data->iv_candidates, cand); |
| |
| if (dump_file && (dump_flags & TDF_DETAILS)) |
| dump_cand (dump_file, cand); |
| } |
| |
| if (important && !cand->important) |
| { |
| cand->important = true; |
| if (dump_file && (dump_flags & TDF_DETAILS)) |
| fprintf (dump_file, "Candidate %d is important\n", cand->id); |
| } |
| |
| if (use) |
| { |
| bitmap_set_bit (use->related_cands, i); |
| if (dump_file && (dump_flags & TDF_DETAILS)) |
| fprintf (dump_file, "Candidate %d is related to use %d\n", |
| cand->id, use->id); |
| } |
| |
| return cand; |
| } |
| |
| /* Returns true if incrementing the induction variable at the end of the LOOP |
| is allowed. |
| |
| The purpose is to avoid splitting latch edge with a biv increment, thus |
| creating a jump, possibly confusing other optimization passes and leaving |
| less freedom to scheduler. So we allow IP_END_POS only if IP_NORMAL_POS |
| is not available (so we do not have a better alternative), or if the latch |
| edge is already nonempty. */ |
| |
| static bool |
| allow_ip_end_pos_p (struct loop *loop) |
| { |
| if (!ip_normal_pos (loop)) |
| return true; |
| |
| if (!empty_block_p (ip_end_pos (loop))) |
| return true; |
| |
| return false; |
| } |
| |
| /* Adds a candidate BASE + STEP * i. Important field is set to IMPORTANT and |
| position to POS. If USE is not NULL, the candidate is set as related to |
| it. The candidate computation is scheduled on all available positions. */ |
| |
| static void |
| add_candidate (struct ivopts_data *data, |
| tree base, tree step, bool important, struct iv_use *use) |
| { |
| if (ip_normal_pos (data->current_loop)) |
| add_candidate_1 (data, base, step, important, IP_NORMAL, use, NULL_TREE); |
| if (ip_end_pos (data->current_loop) |
| && allow_ip_end_pos_p (data->current_loop)) |
| add_candidate_1 (data, base, step, important, IP_END, use, NULL_TREE); |
| } |
| |
| /* Add a standard "0 + 1 * iteration" iv candidate for a |
| type with SIZE bits. */ |
| |
| static void |
| add_standard_iv_candidates_for_size (struct ivopts_data *data, |
| unsigned int size) |
| { |
| tree type = lang_hooks.types.type_for_size (size, true); |
| add_candidate (data, build_int_cst (type, 0), build_int_cst (type, 1), |
| true, NULL); |
| } |
| |
| /* Adds standard iv candidates. */ |
| |
| static void |
| add_standard_iv_candidates (struct ivopts_data *data) |
| { |
| add_standard_iv_candidates_for_size (data, INT_TYPE_SIZE); |
| |
| /* The same for a double-integer type if it is still fast enough. */ |
| if (BITS_PER_WORD >= INT_TYPE_SIZE * 2) |
| add_standard_iv_candidates_for_size (data, INT_TYPE_SIZE * 2); |
| } |
| |
| |
| /* Adds candidates bases on the old induction variable IV. */ |
| |
| static void |
| add_old_iv_candidates (struct ivopts_data *data, struct iv *iv) |
| { |
| tree phi, def; |
| struct iv_cand *cand; |
| |
| add_candidate (data, iv->base, iv->step, true, NULL); |
| |
| /* The same, but with initial value zero. */ |
| add_candidate (data, |
| build_int_cst (TREE_TYPE (iv->base), 0), |
| iv->step, true, NULL); |
| |
| phi = SSA_NAME_DEF_STMT (iv->ssa_name); |
| if (TREE_CODE (phi) == PHI_NODE) |
| { |
| /* Additionally record the possibility of leaving the original iv |
| untouched. */ |
| def = PHI_ARG_DEF_FROM_EDGE (phi, loop_latch_edge (data->current_loop)); |
| cand = add_candidate_1 (data, |
| iv->base, iv->step, true, IP_ORIGINAL, NULL, |
| SSA_NAME_DEF_STMT (def)); |
| cand->var_before = iv->ssa_name; |
| cand->var_after = def; |
| } |
| } |
| |
| /* Adds candidates based on the old induction variables. */ |
| |
| static void |
| add_old_ivs_candidates (struct ivopts_data *data) |
| { |
| unsigned i; |
| struct iv *iv; |
| bitmap_iterator bi; |
| |
| EXECUTE_IF_SET_IN_BITMAP (data->relevant, 0, i, bi) |
| { |
| iv = ver_info (data, i)->iv; |
| if (iv && iv->biv_p && !zero_p (iv->step)) |
| add_old_iv_candidates (data, iv); |
| } |
| } |
| |
| /* Adds candidates based on the value of the induction variable IV and USE. */ |
| |
| static void |
| add_iv_value_candidates (struct ivopts_data *data, |
| struct iv *iv, struct iv_use *use) |
| { |
| add_candidate (data, iv->base, iv->step, false, use); |
| |
| /* The same, but with initial value zero. */ |
| add_candidate (data, build_int_cst (TREE_TYPE (iv->base), 0), |
| iv->step, false, use); |
| } |
| |
| /* Adds candidates based on the address IV and USE. */ |
| |
| static void |
| add_address_candidates (struct ivopts_data *data, |
| struct iv *iv, struct iv_use *use) |
| { |
| tree base, abase; |
| unsigned HOST_WIDE_INT offset; |
| |
| /* First, the trivial choices. */ |
| add_iv_value_candidates (data, iv, use); |
| |
| /* Second, try removing the COMPONENT_REFs. */ |
| if (TREE_CODE (iv->base) == ADDR_EXPR) |
| { |
| base = TREE_OPERAND (iv->base, 0); |
| while (TREE_CODE (base) == COMPONENT_REF |
| || (TREE_CODE (base) == ARRAY_REF |
| && TREE_CODE (TREE_OPERAND (base, 1)) == INTEGER_CST)) |
| base = TREE_OPERAND (base, 0); |
| |
| if (base != TREE_OPERAND (iv->base, 0)) |
| { |
| gcc_assert (TREE_CODE (base) != ALIGN_INDIRECT_REF); |
| gcc_assert (TREE_CODE (base) != MISALIGNED_INDIRECT_REF); |
| |
| if (TREE_CODE (base) == INDIRECT_REF) |
| base = TREE_OPERAND (base, 0); |
| else |
| base = build_addr (base); |
| add_candidate (data, base, iv->step, false, use); |
| } |
| } |
| |
| /* Third, try removing the constant offset. */ |
| abase = iv->base; |
| base = strip_offset (abase, false, &offset); |
| if (offset) |
| add_candidate (data, base, iv->step, false, use); |
| } |
| |
| /* Possibly adds pseudocandidate for replacing the final value of USE by |
| a direct computation. */ |
| |
| static void |
| add_iv_outer_candidates (struct ivopts_data *data, struct iv_use *use) |
| { |
| struct tree_niter_desc *niter; |
| |
| /* We must know where we exit the loop and how many times does it roll. */ |
| niter = niter_for_single_dom_exit (data); |
| if (!niter |
| || !zero_p (niter->may_be_zero)) |
| return; |
| |
| add_candidate_1 (data, NULL, NULL, false, IP_NORMAL, use, NULL_TREE); |
| } |
| |
| /* Adds candidates based on the uses. */ |
| |
| static void |
| add_derived_ivs_candidates (struct ivopts_data *data) |
| { |
| unsigned i; |
| |
| for (i = 0; i < n_iv_uses (data); i++) |
| { |
| struct iv_use *use = iv_use (data, i); |
| |
| if (!use) |
| continue; |
| |
| switch (use->type) |
| { |
| case USE_NONLINEAR_EXPR: |
| case USE_COMPARE: |
| /* Just add the ivs based on the value of the iv used here. */ |
| add_iv_value_candidates (data, use->iv, use); |
| break; |
| |
| case USE_OUTER: |
| add_iv_value_candidates (data, use->iv, use); |
| |
| /* Additionally, add the pseudocandidate for the possibility to |
| replace the final value by a direct computation. */ |
| add_iv_outer_candidates (data, use); |
| break; |
| |
| case USE_ADDRESS: |
| add_address_candidates (data, use->iv, use); |
| break; |
| |
| default: |
| gcc_unreachable (); |
| } |
| } |
| } |
| |
| /* Record important candidates and add them to related_cands bitmaps |
| if needed. */ |
| |
| static void |
| record_important_candidates (struct ivopts_data *data) |
| { |
| unsigned i; |
| struct iv_use *use; |
| |
| for (i = 0; i < n_iv_cands (data); i++) |
| { |
| struct iv_cand *cand = iv_cand (data, i); |
| |
| if (cand->important) |
| bitmap_set_bit (data->important_candidates, i); |
| } |
| |
| data->consider_all_candidates = (n_iv_cands (data) |
| <= CONSIDER_ALL_CANDIDATES_BOUND); |
| |
| if (data->consider_all_candidates) |
| { |
| /* We will not need "related_cands" bitmaps in this case, |
| so release them to decrease peak memory consumption. */ |
| for (i = 0; i < n_iv_uses (data); i++) |
| { |
| use = iv_use (data, i); |
| BITMAP_FREE (use->related_cands); |
| } |
| } |
| else |
| { |
| /* Add important candidates to the related_cands bitmaps. */ |
| for (i = 0; i < n_iv_uses (data); i++) |
| bitmap_ior_into (iv_use (data, i)->related_cands, |
| data->important_candidates); |
| } |
| } |
| |
| /* Finds the candidates for the induction variables. */ |
| |
| static void |
| find_iv_candidates (struct ivopts_data *data) |
| { |
| /* Add commonly used ivs. */ |
| add_standard_iv_candidates (data); |
| |
| /* Add old induction variables. */ |
| add_old_ivs_candidates (data); |
| |
| /* Add induction variables derived from uses. */ |
| add_derived_ivs_candidates (data); |
| |
| /* Record the important candidates. */ |
| record_important_candidates (data); |
| } |
| |
| /* Allocates the data structure mapping the (use, candidate) pairs to costs. |
| If consider_all_candidates is true, we use a two-dimensional array, otherwise |
| we allocate a simple list to every use. */ |
| |
| static void |
| alloc_use_cost_map (struct ivopts_data *data) |
| { |
| unsigned i, size, s, j; |
| |
| for (i = 0; i < n_iv_uses (data); i++) |
| { |
| struct iv_use *use = iv_use (data, i); |
| bitmap_iterator bi; |
| |
| if (data->consider_all_candidates) |
| size = n_iv_cands (data); |
| else |
| { |
| s = 0; |
| EXECUTE_IF_SET_IN_BITMAP (use->related_cands, 0, j, bi) |
| { |
| s++; |
| } |
| |
| /* Round up to the power of two, so that moduling by it is fast. */ |
| for (size = 1; size < s; size <<= 1) |
| continue; |
| } |
| |
| use->n_map_members = size; |
| use->cost_map = xcalloc (size, sizeof (struct cost_pair)); |
| } |
| } |
| |
| /* Sets cost of (USE, CANDIDATE) pair to COST and record that it depends |
| on invariants DEPENDS_ON. */ |
| |
| static void |
| set_use_iv_cost (struct ivopts_data *data, |
| struct iv_use *use, struct iv_cand *cand, unsigned cost, |
| bitmap depends_on) |
| { |
| unsigned i, s; |
| |
| if (cost == INFTY) |
| { |
| BITMAP_FREE (depends_on); |
| return; |
| } |
| |
| if (data->consider_all_candidates) |
| { |
| use->cost_map[cand->id].cand = cand; |
| use->cost_map[cand->id].cost = cost; |
| use->cost_map[cand->id].depends_on = depends_on; |
| return; |
| } |
| |
| /* n_map_members is a power of two, so this computes modulo. */ |
| s = cand->id & (use->n_map_members - 1); |
| for (i = s; i < use->n_map_members; i++) |
| if (!use->cost_map[i].cand) |
| goto found; |
| for (i = 0; i < s; i++) |
| if (!use->cost_map[i].cand) |
| goto found; |
| |
| gcc_unreachable (); |
| |
| found: |
| use->cost_map[i].cand = cand; |
| use->cost_map[i].cost = cost; |
| use->cost_map[i].depends_on = depends_on; |
| } |
| |
| /* Gets cost of (USE, CANDIDATE) pair. */ |
| |
| static struct cost_pair * |
| get_use_iv_cost (struct ivopts_data *data, struct iv_use *use, |
| struct iv_cand *cand) |
| { |
| unsigned i, s; |
| struct cost_pair *ret; |
| |
| if (!cand) |
| return NULL; |
| |
| if (data->consider_all_candidates) |
| { |
| ret = use->cost_map + cand->id; |
| if (!ret->cand) |
| return NULL; |
| |
| return ret; |
| } |
| |
| /* n_map_members is a power of two, so this computes modulo. */ |
| s = cand->id & (use->n_map_members - 1); |
| for (i = s; i < use->n_map_members; i++) |
| if (use->cost_map[i].cand == cand) |
| return use->cost_map + i; |
| |
| for (i = 0; i < s; i++) |
| if (use->cost_map[i].cand == cand) |
| return use->cost_map + i; |
| |
| return NULL; |
| } |
| |
| /* Returns estimate on cost of computing SEQ. */ |
| |
| static unsigned |
| seq_cost (rtx seq) |
| { |
| unsigned cost = 0; |
| rtx set; |
| |
| for (; seq; seq = NEXT_INSN (seq)) |
| { |
| set = single_set (seq); |
| if (set) |
| cost += rtx_cost (set, SET); |
| else |
| cost++; |
| } |
| |
| return cost; |
| } |
| |
| /* Produce DECL_RTL for object obj so it looks like it is stored in memory. */ |
| static rtx |
| produce_memory_decl_rtl (tree obj, int *regno) |
| { |
| rtx x; |
| if (!obj) |
| abort (); |
| if (TREE_STATIC (obj) || DECL_EXTERNAL (obj)) |
| { |
| const char *name = IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (obj)); |
| x = gen_rtx_SYMBOL_REF (Pmode, name); |
| } |
| else |
| x = gen_raw_REG (Pmode, (*regno)++); |
| |
| return gen_rtx_MEM (DECL_MODE (obj), x); |
| } |
| |
| /* Prepares decl_rtl for variables referred in *EXPR_P. Callback for |
| walk_tree. DATA contains the actual fake register number. */ |
| |
| static tree |
| prepare_decl_rtl (tree *expr_p, int *ws, void *data) |
| { |
| tree obj = NULL_TREE; |
| rtx x = NULL_RTX; |
| int *regno = data; |
| |
| switch (TREE_CODE (*expr_p)) |
| { |
| case ADDR_EXPR: |
| for (expr_p = &TREE_OPERAND (*expr_p, 0); |
| handled_component_p (*expr_p); |
| expr_p = &TREE_OPERAND (*expr_p, 0)) |
| continue; |
| obj = *expr_p; |
| if (DECL_P (obj)) |
| x = produce_memory_decl_rtl (obj, regno); |
| break; |
| |
| case SSA_NAME: |
| *ws = 0; |
| obj = SSA_NAME_VAR (*expr_p); |
| if (!DECL_RTL_SET_P (obj)) |
| x = gen_raw_REG (DECL_MODE (obj), (*regno)++); |
| break; |
| |
| case VAR_DECL: |
| case PARM_DECL: |
| case RESULT_DECL: |
| *ws = 0; |
| obj = *expr_p; |
| |
| if (DECL_RTL_SET_P (obj)) |
| break; |
| |
| if (DECL_MODE (obj) == BLKmode) |
| x = produce_memory_decl_rtl (obj, regno); |
| else |
| x = gen_raw_REG (DECL_MODE (obj), (*regno)++); |
| |
| break; |
| |
| default: |
| break; |
| } |
| |
| if (x) |
| { |
| VARRAY_PUSH_GENERIC_PTR_NOGC (decl_rtl_to_reset, obj); |
| SET_DECL_RTL (obj, x); |
| } |
| |
| return NULL_TREE; |
| } |
| |
| /* Determines cost of the computation of EXPR. */ |
| |
| static unsigned |
| computation_cost (tree expr) |
| { |
| rtx seq, rslt; |
| tree type = TREE_TYPE (expr); |
| unsigned cost; |
| /* Avoid using hard regs in ways which may be unsupported. */ |
| int regno = LAST_VIRTUAL_REGISTER + 1; |
| |
| walk_tree (&expr, prepare_decl_rtl, ®no, NULL); |
| start_sequence (); |
| rslt = expand_expr (expr, NULL_RTX, TYPE_MODE (type), EXPAND_NORMAL); |
| seq = get_insns (); |
| end_sequence (); |
| |
| cost = seq_cost (seq); |
| if (GET_CODE (rslt) == MEM) |
| cost += address_cost (XEXP (rslt, 0), TYPE_MODE (type)); |
| |
| return cost; |
| } |
| |
| /* Returns variable containing the value of candidate CAND at statement AT. */ |
| |
| static tree |
| var_at_stmt (struct loop *loop, struct iv_cand *cand, tree stmt) |
| { |
| if (stmt_after_increment (loop, cand, stmt)) |
| return cand->var_after; |
| else |
| return cand->var_before; |
| } |
| |
| /* Determines the expression by that USE is expressed from induction variable |
| CAND at statement AT in LOOP. */ |
| |
| static tree |
| get_computation_at (struct loop *loop, |
| struct iv_use *use, struct iv_cand *cand, tree at) |
| { |
| tree ubase = use->iv->base; |
| tree ustep = use->iv->step; |
| tree cbase = cand->iv->base; |
| tree cstep = cand->iv->step; |
| tree utype = TREE_TYPE (ubase), ctype = TREE_TYPE (cbase); |
| tree uutype; |
| tree expr, delta; |
| tree ratio; |
| unsigned HOST_WIDE_INT ustepi, cstepi; |
| HOST_WIDE_INT ratioi; |
| |
| if (TYPE_PRECISION (utype) > TYPE_PRECISION (ctype)) |
| { |
| /* We do not have a precision to express the values of use. */ |
| return NULL_TREE; |
| } |
| |
| expr = var_at_stmt (loop, cand, at); |
| |
| if (TREE_TYPE (expr) != ctype) |
| { |
| /* This may happen with the original ivs. */ |
| expr = fold_convert (ctype, expr); |
| } |
| |
| if (TYPE_UNSIGNED (utype)) |
| uutype = utype; |
| else |
| { |
| uutype = unsigned_type_for (utype); |
| ubase = fold_convert (uutype, ubase); |
| ustep = fold_convert (uutype, ustep); |
| } |
| |
| if (uutype != ctype) |
| { |
| expr = fold_convert (uutype, expr); |
| cbase = fold_convert (uutype, cbase); |
| cstep = fold_convert (uutype, cstep); |
| } |
| |
| if (!cst_and_fits_in_hwi (cstep) |
| || !cst_and_fits_in_hwi (ustep)) |
| return NULL_TREE; |
| |
| ustepi = int_cst_value (ustep); |
| cstepi = int_cst_value (cstep); |
| |
| if (!divide (TYPE_PRECISION (uutype), ustepi, cstepi, &ratioi)) |
| { |
| /* TODO maybe consider case when ustep divides cstep and the ratio is |
| a power of 2 (so that the division is fast to execute)? We would |
| need to be much more careful with overflows etc. then. */ |
| return NULL_TREE; |
| } |
| |
| /* We may need to shift the value if we are after the increment. */ |
| if (stmt_after_increment (loop, cand, at)) |
| cbase = fold (build2 (PLUS_EXPR, uutype, cbase, cstep)); |
| |
| /* use = ubase - ratio * cbase + ratio * var. |
| |
| In general case ubase + ratio * (var - cbase) could be better (one less |
| multiplication), but often it is possible to eliminate redundant parts |
| of computations from (ubase - ratio * cbase) term, and if it does not |
| happen, fold is able to apply the distributive law to obtain this form |
| anyway. */ |
| |
| if (ratioi == 1) |
| { |
| delta = fold (build2 (MINUS_EXPR, uutype, ubase, cbase)); |
| expr = fold (build2 (PLUS_EXPR, uutype, expr, delta)); |
| } |
| else if (ratioi == -1) |
| { |
| delta = fold (build2 (PLUS_EXPR, uutype, ubase, cbase)); |
| expr = fold (build2 (MINUS_EXPR, uutype, delta, expr)); |
| } |
| else |
| { |
| ratio = build_int_cst_type (uutype, ratioi); |
| delta = fold (build2 (MULT_EXPR, uutype, ratio, cbase)); |
| delta = fold (build2 (MINUS_EXPR, uutype, ubase, delta)); |
| expr = fold (build2 (MULT_EXPR, uutype, ratio, expr)); |
| expr = fold (build2 (PLUS_EXPR, uutype, delta, expr)); |
| } |
| |
| return fold_convert (utype, expr); |
| } |
| |
| /* Determines the expression by that USE is expressed from induction variable |
| CAND in LOOP. */ |
| |
| static tree |
| get_computation (struct loop *loop, struct iv_use *use, struct iv_cand *cand) |
| { |
| return get_computation_at (loop, use, cand, use->stmt); |
| } |
| |
| /* Returns cost of addition in MODE. */ |
| |
| static unsigned |
| add_cost (enum machine_mode mode) |
| { |
| static unsigned costs[NUM_MACHINE_MODES]; |
| rtx seq; |
| unsigned cost; |
| |
| if (costs[mode]) |
| return costs[mode]; |
| |
| start_sequence (); |
| force_operand (gen_rtx_fmt_ee (PLUS, mode, |
| gen_raw_REG (mode, FIRST_PSEUDO_REGISTER), |
| gen_raw_REG (mode, FIRST_PSEUDO_REGISTER + 1)), |
| NULL_RTX); |
| seq = get_insns (); |
| end_sequence (); |
| |
| cost = seq_cost (seq); |
| if (!cost) |
| cost = 1; |
| |
| costs[mode] = cost; |
| |
| if (dump_file && (dump_flags & TDF_DETAILS)) |
| fprintf (dump_file, "Addition in %s costs %d\n", |
| GET_MODE_NAME (mode), cost); |
| return cost; |
| } |
| |
| /* Entry in a hashtable of already known costs for multiplication. */ |
| struct mbc_entry |
| { |
| HOST_WIDE_INT cst; /* The constant to multiply by. */ |
| enum machine_mode mode; /* In mode. */ |
| unsigned cost; /* The cost. */ |
| }; |
| |
| /* Counts hash value for the ENTRY. */ |
| |
| static hashval_t |
| mbc_entry_hash (const void *entry) |
| { |
| const struct mbc_entry *e = entry; |
| |
| return 57 * (hashval_t) e->mode + (hashval_t) (e->cst % 877); |
| } |
| |
| /* Compares the hash table entries ENTRY1 and ENTRY2. */ |
| |
| static int |
| mbc_entry_eq (const void *entry1, const void *entry2) |
| { |
| const struct mbc_entry *e1 = entry1; |
| const struct mbc_entry *e2 = entry2; |
| |
| return (e1->mode == e2->mode |
| && e1->cst == e2->cst); |
| } |
| |
| /* Returns cost of multiplication by constant CST in MODE. */ |
| |
| static unsigned |
| multiply_by_cost (HOST_WIDE_INT cst, enum machine_mode mode) |
| { |
| static htab_t costs; |
| struct mbc_entry **cached, act; |
| rtx seq; |
| unsigned cost; |
| |
| if (!costs) |
| costs = htab_create (100, mbc_entry_hash, mbc_entry_eq, free); |
| |
| act.mode = mode; |
| act.cst = cst; |
| cached = (struct mbc_entry **) htab_find_slot (costs, &act, INSERT); |
| if (*cached) |
| return (*cached)->cost; |
| |
| *cached = xmalloc (sizeof (struct mbc_entry)); |
| (*cached)->mode = mode; |
| (*cached)->cst = cst; |
| |
| start_sequence (); |
| expand_mult (mode, gen_raw_REG (mode, FIRST_PSEUDO_REGISTER), GEN_INT (cst), |
| NULL_RTX, 0); |
| seq = get_insns (); |
| end_sequence (); |
| |
| cost = seq_cost (seq); |
| |
| if (dump_file && (dump_flags & TDF_DETAILS)) |
| fprintf (dump_file, "Multiplication by %d in %s costs %d\n", |
| (int) cst, GET_MODE_NAME (mode), cost); |
| |
| (*cached)->cost = cost; |
| |
| return cost; |
| } |
| |
| /* Returns cost of address in shape symbol + var + OFFSET + RATIO * index. |
| If SYMBOL_PRESENT is false, symbol is omitted. If VAR_PRESENT is false, |
| variable is omitted. The created memory accesses MODE. |
| |
| TODO -- there must be some better way. This all is quite crude. */ |
| |
| static unsigned |
| get_address_cost (bool symbol_present, bool var_present, |
| unsigned HOST_WIDE_INT offset, HOST_WIDE_INT ratio) |
| { |
| #define MAX_RATIO 128 |
| static sbitmap valid_mult; |
| static HOST_WIDE_INT rat, off; |
| static HOST_WIDE_INT min_offset, max_offset; |
| static unsigned costs[2][2][2][2]; |
| unsigned cost, acost; |
| rtx seq, addr, base; |
| bool offset_p, ratio_p; |
| rtx reg1; |
| HOST_WIDE_INT s_offset; |
| unsigned HOST_WIDE_INT mask; |
| unsigned bits; |
| |
| if (!valid_mult) |
| { |
| HOST_WIDE_INT i; |
| |
| reg1 = gen_raw_REG (Pmode, FIRST_PSEUDO_REGISTER); |
| |
| addr = gen_rtx_fmt_ee (PLUS, Pmode, reg1, NULL_RTX); |
| for (i = 1; i <= 1 << 20; i <<= 1) |
| { |
| XEXP (addr, 1) = GEN_INT (i); |
| if (!memory_address_p (Pmode, addr)) |
| break; |
| } |
| max_offset = i >> 1; |
| off = max_offset; |
| |
| for (i = 1; i <= 1 << 20; i <<= 1) |
| { |
| XEXP (addr, 1) = GEN_INT (-i); |
| if (!memory_address_p (Pmode, addr)) |
| break; |
| } |
| min_offset = -(i >> 1); |
| |
| if (dump_file && (dump_flags & TDF_DETAILS)) |
| { |
| fprintf (dump_file, "get_address_cost:\n"); |
| fprintf (dump_file, " min offset %d\n", (int) min_offset); |
| fprintf (dump_file, " max offset %d\n", (int) max_offset); |
| } |
| |
| valid_mult = sbitmap_alloc (2 * MAX_RATIO + 1); |
| sbitmap_zero (valid_mult); |
| rat = 1; |
| addr = gen_rtx_fmt_ee (MULT, Pmode, reg1, NULL_RTX); |
| for (i = -MAX_RATIO; i <= MAX_RATIO; i++) |
| { |
| XEXP (addr, 1) = GEN_INT (i); |
| if (memory_address_p (Pmode, addr)) |
| { |
| SET_BIT (valid_mult, i + MAX_RATIO); |
| rat = i; |
| } |
| } |
| |
| if (dump_file && (dump_flags & TDF_DETAILS)) |
| { |
| fprintf (dump_file, " allowed multipliers:"); |
| for (i = -MAX_RATIO; i <= MAX_RATIO; i++) |
| if (TEST_BIT (valid_mult, i + MAX_RATIO)) |
| fprintf (dump_file, " %d", (int) i); |
| fprintf (dump_file, "\n"); |
| fprintf (dump_file, "\n"); |
| } |
| } |
| |
| bits = GET_MODE_BITSIZE (Pmode); |
| mask = ~(~(unsigned HOST_WIDE_INT) 0 << (bits - 1) << 1); |
| offset &= mask; |
| if ((offset >> (bits - 1) & 1)) |
| offset |= ~mask; |
| s_offset = offset; |
| |
| cost = 0; |
| offset_p = (s_offset != 0 |
| && min_offset <= s_offset && s_offset <= max_offset); |
| ratio_p = (ratio != 1 |
| && -MAX_RATIO <= ratio && ratio <= MAX_RATIO |
| && TEST_BIT (valid_mult, ratio + MAX_RATIO)); |
| |
| if (ratio != 1 && !ratio_p) |
| cost += multiply_by_cost (ratio, Pmode); |
| |
| if (s_offset && !offset_p && !symbol_present) |
| { |
| cost += add_cost (Pmode); |
| var_present = true; |
| } |
| |
| acost = costs[symbol_present][var_present][offset_p][ratio_p]; |
| if (!acost) |
| { |
| acost = 0; |
| |
| addr = gen_raw_REG (Pmode, FIRST_PSEUDO_REGISTER); |
| reg1 = gen_raw_REG (Pmode, FIRST_PSEUDO_REGISTER + 1); |
| if (ratio_p) |
| addr = gen_rtx_fmt_ee (MULT, Pmode, addr, GEN_INT (rat)); |
| |
| if (var_present) |
| addr = gen_rtx_fmt_ee (PLUS, Pmode, addr, reg1); |
| |
| if (symbol_present) |
| { |
| base = gen_rtx_SYMBOL_REF (Pmode, ggc_strdup ("")); |
| if (offset_p) |
| base = gen_rtx_fmt_e (CONST, Pmode, |
| gen_rtx_fmt_ee (PLUS, Pmode, |
| base, |
| GEN_INT (off))); |
| } |
| else if (offset_p) |
| base = GEN_INT (off); |
| else |
| base = NULL_RTX; |
| |
| if (base) |
| addr = gen_rtx_fmt_ee (PLUS, Pmode, addr, base); |
| |
| start_sequence (); |
| addr = memory_address (Pmode, addr); |
| seq = get_insns (); |
| end_sequence (); |
| |
| acost = seq_cost (seq); |
| acost += address_cost (addr, Pmode); |
| |
| if (!acost) |
| acost = 1; |
| costs[symbol_present][var_present][offset_p][ratio_p] = acost; |
| } |
| |
| return cost + acost; |
| } |
| |
| /* Records invariants in *EXPR_P. Callback for walk_tree. DATA contains |
| the bitmap to that we should store it. */ |
| |
| static struct ivopts_data *fd_ivopts_data; |
| static tree |
| find_depends (tree *expr_p, int *ws ATTRIBUTE_UNUSED, void *data) |
| { |
| bitmap *depends_on = data; |
| struct version_info *info; |
| |
| if (TREE_CODE (*expr_p) != SSA_NAME) |
| return NULL_TREE; |
| info = name_info (fd_ivopts_data, *expr_p); |
| |
| if (!info->inv_id || info->has_nonlin_use) |
| return NULL_TREE; |
| |
| if (!*depends_on) |
| *depends_on = BITMAP_ALLOC (NULL); |
| bitmap_set_bit (*depends_on, info->inv_id); |
| |
| return NULL_TREE; |
| } |
| |
| /* Estimates cost of forcing EXPR into a variable. DEPENDS_ON is a set of the |
| invariants the computation depends on. */ |
| |
| static unsigned |
| force_var_cost (struct ivopts_data *data, |
| tree expr, bitmap *depends_on) |
| { |
| static bool costs_initialized = false; |
| static unsigned integer_cost; |
| static unsigned symbol_cost; |
| static unsigned address_cost; |
| tree op0, op1; |
| unsigned cost0, cost1, cost; |
| enum machine_mode mode; |
| |
| if (!costs_initialized) |
| { |
| tree var = create_tmp_var_raw (integer_type_node, "test_var"); |
| rtx x = gen_rtx_MEM (DECL_MODE (var), |
| gen_rtx_SYMBOL_REF (Pmode, "test_var")); |
| tree addr; |
| tree type = build_pointer_type (integer_type_node); |
| |
| integer_cost = computation_cost (build_int_cst_type (integer_type_node, |
| 2000)); |
| |
| SET_DECL_RTL (var, x); |
| TREE_STATIC (var) = 1; |
| addr = build1 (ADDR_EXPR, type, var); |
| symbol_cost = computation_cost (addr) + 1; |
| |
| address_cost |
| = computation_cost (build2 (PLUS_EXPR, type, |
| addr, |
| build_int_cst_type (type, 2000))) + 1; |
| if (dump_file && (dump_flags & TDF_DETAILS)) |
| { |
| fprintf (dump_file, "force_var_cost:\n"); |
| fprintf (dump_file, " integer %d\n", (int) integer_cost); |
| fprintf (dump_file, " symbol %d\n", (int) symbol_cost); |
| fprintf (dump_file, " address %d\n", (int) address_cost); |
| fprintf (dump_file, " other %d\n", (int) target_spill_cost); |
| fprintf (dump_file, "\n"); |
| } |
| |
| costs_initialized = true; |
| } |
| |
| STRIP_NOPS (expr); |
| |
| if (depends_on) |
| { |
| fd_ivopts_data = data; |
| walk_tree (&expr, find_depends, depends_on, NULL); |
| } |
| |
| if (SSA_VAR_P (expr)) |
| return 0; |
| |
| if (TREE_INVARIANT (expr)) |
| { |
| if (TREE_CODE (expr) == INTEGER_CST) |
| return integer_cost; |
| |
| if (TREE_CODE (expr) == ADDR_EXPR) |
| { |
| tree obj = TREE_OPERAND (expr, 0); |
| |
| if (TREE_CODE (obj) == VAR_DECL |
| || TREE_CODE (obj) == PARM_DECL |
| || TREE_CODE (obj) == RESULT_DECL) |
| return symbol_cost; |
| } |
| |
| return address_cost; |
| } |
| |
| switch (TREE_CODE (expr)) |
| { |
| case PLUS_EXPR: |
| case MINUS_EXPR: |
| case MULT_EXPR: |
| op0 = TREE_OPERAND (expr, 0); |
| op1 = TREE_OPERAND (expr, 1); |
| STRIP_NOPS (op0); |
| STRIP_NOPS (op1); |
| |
| if (is_gimple_val (op0)) |
| cost0 = 0; |
| else |
| cost0 = force_var_cost (data, op0, NULL); |
| |
| if (is_gimple_val (op1)) |
| cost1 = 0; |
| else |
| cost1 = force_var_cost (data, op1, NULL); |
| |
| break; |
| |
| default: |
| /* Just an arbitrary value, FIXME. */ |
| return target_spill_cost; |
| } |
| |
| mode = TYPE_MODE (TREE_TYPE (expr)); |
| switch (TREE_CODE (expr)) |
| { |
| case PLUS_EXPR: |
| case MINUS_EXPR: |
| cost = add_cost (mode); |
| break; |
| |
| case MULT_EXPR: |
| if (cst_and_fits_in_hwi (op0)) |
| cost = multiply_by_cost (int_cst_value (op0), mode); |
| else if (cst_and_fits_in_hwi (op1)) |
| cost = multiply_by_cost (int_cst_value (op1), mode); |
| else |
| return target_spill_cost; |
| break; |
| |
| default: |
| gcc_unreachable (); |
| } |
| |
| cost += cost0; |
| cost += cost1; |
| |
| /* Bound the cost by target_spill_cost. The parts of complicated |
| computations often are either loop invariant or at least can |
| be shared between several iv uses, so letting this grow without |
| limits would not give reasonable results. */ |
| return cost < target_spill_cost ? cost : target_spill_cost; |
| } |
| |
| /* Estimates cost of expressing address ADDR as var + symbol + offset. The |
| value of offset is added to OFFSET, SYMBOL_PRESENT and VAR_PRESENT are set |
| to false if the corresponding part is missing. DEPENDS_ON is a set of the |
| invariants the computation depends on. */ |
| |
| static unsigned |
| split_address_cost (struct ivopts_data *data, |
| tree addr, bool *symbol_present, bool *var_present, |
| unsigned HOST_WIDE_INT *offset, bitmap *depends_on) |
| { |
| tree core; |
| HOST_WIDE_INT bitsize; |
| HOST_WIDE_INT bitpos; |
| tree toffset; |
| enum machine_mode mode; |
| int unsignedp, volatilep; |
| |
| core = get_inner_reference (addr, &bitsize, &bitpos, &toffset, &mode, |
| &unsignedp, &volatilep, false); |
| |
| if (toffset != 0 |
| || bitpos % BITS_PER_UNIT != 0 |
| || TREE_CODE (core) != VAR_DECL) |
| { |
| *symbol_present = false; |
| *var_present = true; |
| fd_ivopts_data = data; |
| walk_tree (&addr, find_depends, depends_on, NULL); |
| return target_spill_cost; |
| } |
| |
| *offset += bitpos / BITS_PER_UNIT; |
| if (TREE_STATIC (core) |
| || DECL_EXTERNAL (core)) |
| { |
| *symbol_present = true; |
| *var_present = false; |
| return 0; |
| } |
| |
| *symbol_present = false; |
| *var_present = true; |
| return 0; |
| } |
| |
| /* Estimates cost of expressing difference of addresses E1 - E2 as |
| var + symbol + offset. The value of offset is added to OFFSET, |
| SYMBOL_PRESENT and VAR_PRESENT are set to false if the corresponding |
| part is missing. DEPENDS_ON is a set of the invariants the computation |
| depends on. */ |
| |
| static unsigned |
| ptr_difference_cost (struct ivopts_data *data, |
| tree e1, tree e2, bool *symbol_present, bool *var_present, |
| unsigned HOST_WIDE_INT *offset, bitmap *depends_on) |
| { |
| HOST_WIDE_INT diff = 0; |
| unsigned cost; |
| |
| gcc_assert (TREE_CODE (e1) == ADDR_EXPR); |
| |
| if (ptr_difference_const (e1, e2, &diff)) |
| { |
| *offset += diff; |
| *symbol_present = false; |
| *var_present = false; |
| return 0; |
| } |
| |
| if (e2 == integer_zero_node) |
| return split_address_cost (data, TREE_OPERAND (e1, 0), |
| symbol_present, var_present, offset, depends_on); |
| |
| *symbol_present = false; |
| *var_present = true; |
| |
| cost = force_var_cost (data, e1, depends_on); |
| cost += force_var_cost (data, e2, depends_on); |
| cost += add_cost (Pmode); |
| |
| return cost; |
| } |
| |
| /* Estimates cost of expressing difference E1 - E2 as |
| var + symbol + offset. The value of offset is added to OFFSET, |
| SYMBOL_PRESENT and VAR_PRESENT are set to false if the corresponding |
| part is missing. DEPENDS_ON is a set of the invariants the computation |
| depends on. */ |
| |
| static unsigned |
| difference_cost (struct ivopts_data *data, |
| tree e1, tree e2, bool *symbol_present, bool *var_present, |
| unsigned HOST_WIDE_INT *offset, bitmap *depends_on) |
| { |
| unsigned cost; |
| enum machine_mode mode = TYPE_MODE (TREE_TYPE (e1)); |
| unsigned HOST_WIDE_INT off1, off2; |
| |
| e1 = strip_offset (e1, false, &off1); |
| e2 = strip_offset (e2, false, &off2); |
| *offset += off1 - off2; |
| |
| STRIP_NOPS (e1); |
| STRIP_NOPS (e2); |
| |
| if (TREE_CODE (e1) == ADDR_EXPR) |
| return ptr_difference_cost (data, e1, e2, symbol_present, var_present, offset, |
| depends_on); |
| *symbol_present = false; |
| |
| if (operand_equal_p (e1, e2, 0)) |
| { |
| *var_present = false; |
| return 0; |
| } |
| *var_present = true; |
| if (zero_p (e2)) |
| return force_var_cost (data, e1, depends_on); |
| |
| if (zero_p (e1)) |
| { |
| cost = force_var_cost (data, e2, depends_on); |
| cost += multiply_by_cost (-1, mode); |
| |
| return cost; |
| } |
| |
| cost = force_var_cost (data, e1, depends_on); |
| cost += force_var_cost (data, e2, depends_on); |
| cost += add_cost (mode); |
| |
| return cost; |
| } |
| |
| /* Determines the cost of the computation by that USE is expressed |
| from induction variable CAND. If ADDRESS_P is true, we just need |
| to create an address from it, otherwise we want to get it into |
| register. A set of invariants we depend on is stored in |
| DEPENDS_ON. AT is the statement at that the value is computed. */ |
| |
| static unsigned |
| get_computation_cost_at (struct ivopts_data *data, |
| struct iv_use *use, struct iv_cand *cand, |
| bool address_p, bitmap *depends_on, tree at) |
| { |
| tree ubase = use->iv->base, ustep = use->iv->step; |
| tree cbase, cstep; |
| tree utype = TREE_TYPE (ubase), ctype; |
| unsigned HOST_WIDE_INT ustepi, cstepi, offset = 0; |
| HOST_WIDE_INT ratio, aratio; |
| bool var_present, symbol_present; |
| unsigned cost = 0, n_sums; |
| |
| *depends_on = NULL; |
| |
| /* Only consider real candidates. */ |
| if (!cand->iv) |
| return INFTY; |
| |
| cbase = cand->iv->base; |
| cstep = cand->iv->step; |
| ctype = TREE_TYPE (cbase); |
| |
| if (TYPE_PRECISION (utype) > TYPE_PRECISION (ctype)) |
| { |
| /* We do not have a precision to express the values of use. */ |
| return INFTY; |
| } |
| |
| if (address_p) |
| { |
| /* Do not try to express address of an object with computation based |
| on address of a different object. This may cause problems in rtl |
| level alias analysis (that does not expect this to be happening, |
| as this is illegal in C), and would be unlikely to be useful |
| anyway. */ |
| if (use->iv->base_object |
| && cand->iv->base_object |
| && !operand_equal_p (use->iv->base_object, cand->iv->base_object, 0)) |
| return INFTY; |
| } |
| |
| if (!cst_and_fits_in_hwi (ustep) |
| || !cst_and_fits_in_hwi (cstep)) |
| return INFTY; |
| |
| if (TREE_CODE (ubase) == INTEGER_CST |
| && !cst_and_fits_in_hwi (ubase)) |
| goto fallback; |
| |
| if (TREE_CODE (cbase) == INTEGER_CST |
| && !cst_and_fits_in_hwi (cbase)) |
| goto fallback; |
| |
| ustepi = int_cst_value (ustep); |
| cstepi = int_cst_value (cstep); |
| |
| if (TYPE_PRECISION (utype) != TYPE_PRECISION (ctype)) |
| { |
| /* TODO -- add direct handling of this case. */ |
| goto fallback; |
| } |
| |
| if (!divide (TYPE_PRECISION (utype), ustepi, cstepi, &ratio)) |
| return INFTY; |
| |
| /* use = ubase + ratio * (var - cbase). If either cbase is a constant |
| or ratio == 1, it is better to handle this like |
| |
| ubase - ratio * cbase + ratio * var |
| |
| (also holds in the case ratio == -1, TODO. */ |
| |
| if (TREE_CODE (cbase) == INTEGER_CST) |
| { |
| offset = - ratio * int_cst_value (cbase); |
| cost += difference_cost (data, |
| ubase, integer_zero_node, |
| &symbol_present, &var_present, &offset, |
| depends_on); |
| } |
| else if (ratio == 1) |
| { |
| cost += difference_cost (data, |
| ubase, cbase, |
| &symbol_present, &var_present, &offset, |
| depends_on); |
| } |
| else |
| { |
| cost += force_var_cost (data, cbase, depends_on); |
| cost += add_cost (TYPE_MODE (ctype)); |
| cost += difference_cost (data, |
| ubase, integer_zero_node, |
| &symbol_present, &var_present, &offset, |
| depends_on); |
| } |
| |
| /* If we are after the increment, the value of the candidate is higher by |
| one iteration. */ |
| if (stmt_after_increment (data->current_loop, cand, at)) |
| offset -= ratio * cstepi; |
| |
| /* Now the computation is in shape symbol + var1 + const + ratio * var2. |
| (symbol/var/const parts may be omitted). If we are looking for an address, |
|