| /* RTL-level loop invariant motion. |
| Copyright (C) 2004-2015 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/>. */ |
| |
| /* This implements the loop invariant motion pass. It is very simple |
| (no calls, no loads/stores, etc.). This should be sufficient to cleanup |
| things like address arithmetics -- other more complicated invariants should |
| be eliminated on GIMPLE either in tree-ssa-loop-im.c or in tree-ssa-pre.c. |
| |
| We proceed loop by loop -- it is simpler than trying to handle things |
| globally and should not lose much. First we inspect all sets inside loop |
| and create a dependency graph on insns (saying "to move this insn, you must |
| also move the following insns"). |
| |
| We then need to determine what to move. We estimate the number of registers |
| used and move as many invariants as possible while we still have enough free |
| registers. We prefer the expensive invariants. |
| |
| Then we move the selected invariants out of the loop, creating a new |
| temporaries for them if necessary. */ |
| |
| #include "config.h" |
| #include "system.h" |
| #include "coretypes.h" |
| #include "tm.h" |
| #include "hard-reg-set.h" |
| #include "rtl.h" |
| #include "tm_p.h" |
| #include "obstack.h" |
| #include "predict.h" |
| #include "vec.h" |
| #include "hashtab.h" |
| #include "hash-set.h" |
| #include "machmode.h" |
| #include "input.h" |
| #include "function.h" |
| #include "dominance.h" |
| #include "cfg.h" |
| #include "cfgrtl.h" |
| #include "basic-block.h" |
| #include "cfgloop.h" |
| #include "symtab.h" |
| #include "flags.h" |
| #include "statistics.h" |
| #include "double-int.h" |
| #include "real.h" |
| #include "fixed-value.h" |
| #include "alias.h" |
| #include "wide-int.h" |
| #include "inchash.h" |
| #include "tree.h" |
| #include "insn-config.h" |
| #include "expmed.h" |
| #include "dojump.h" |
| #include "explow.h" |
| #include "calls.h" |
| #include "emit-rtl.h" |
| #include "varasm.h" |
| #include "stmt.h" |
| #include "expr.h" |
| #include "recog.h" |
| #include "target.h" |
| #include "df.h" |
| #include "hash-table.h" |
| #include "except.h" |
| #include "params.h" |
| #include "regs.h" |
| #include "ira.h" |
| #include "dumpfile.h" |
| |
| /* The data stored for the loop. */ |
| |
| struct loop_data |
| { |
| struct loop *outermost_exit; /* The outermost exit of the loop. */ |
| bool has_call; /* True if the loop contains a call. */ |
| /* Maximal register pressure inside loop for given register class |
| (defined only for the pressure classes). */ |
| int max_reg_pressure[N_REG_CLASSES]; |
| /* Loop regs referenced and live pseudo-registers. */ |
| bitmap_head regs_ref; |
| bitmap_head regs_live; |
| }; |
| |
| #define LOOP_DATA(LOOP) ((struct loop_data *) (LOOP)->aux) |
| |
| /* The description of an use. */ |
| |
| struct use |
| { |
| rtx *pos; /* Position of the use. */ |
| rtx_insn *insn; /* The insn in that the use occurs. */ |
| unsigned addr_use_p; /* Whether the use occurs in an address. */ |
| struct use *next; /* Next use in the list. */ |
| }; |
| |
| /* The description of a def. */ |
| |
| struct def |
| { |
| struct use *uses; /* The list of uses that are uniquely reached |
| by it. */ |
| unsigned n_uses; /* Number of such uses. */ |
| unsigned n_addr_uses; /* Number of uses in addresses. */ |
| unsigned invno; /* The corresponding invariant. */ |
| }; |
| |
| /* The data stored for each invariant. */ |
| |
| struct invariant |
| { |
| /* The number of the invariant. */ |
| unsigned invno; |
| |
| /* The number of the invariant with the same value. */ |
| unsigned eqto; |
| |
| /* The number of invariants which eqto this. */ |
| unsigned eqno; |
| |
| /* If we moved the invariant out of the loop, the register that contains its |
| value. */ |
| rtx reg; |
| |
| /* If we moved the invariant out of the loop, the original regno |
| that contained its value. */ |
| int orig_regno; |
| |
| /* The definition of the invariant. */ |
| struct def *def; |
| |
| /* The insn in that it is defined. */ |
| rtx_insn *insn; |
| |
| /* Whether it is always executed. */ |
| bool always_executed; |
| |
| /* Whether to move the invariant. */ |
| bool move; |
| |
| /* Whether the invariant is cheap when used as an address. */ |
| bool cheap_address; |
| |
| /* Cost of the invariant. */ |
| unsigned cost; |
| |
| /* The invariants it depends on. */ |
| bitmap depends_on; |
| |
| /* Used for detecting already visited invariants during determining |
| costs of movements. */ |
| unsigned stamp; |
| }; |
| |
| /* Currently processed loop. */ |
| static struct loop *curr_loop; |
| |
| /* Table of invariants indexed by the df_ref uid field. */ |
| |
| static unsigned int invariant_table_size = 0; |
| static struct invariant ** invariant_table; |
| |
| /* Entry for hash table of invariant expressions. */ |
| |
| struct invariant_expr_entry |
| { |
| /* The invariant. */ |
| struct invariant *inv; |
| |
| /* Its value. */ |
| rtx expr; |
| |
| /* Its mode. */ |
| machine_mode mode; |
| |
| /* Its hash. */ |
| hashval_t hash; |
| }; |
| |
| /* The actual stamp for marking already visited invariants during determining |
| costs of movements. */ |
| |
| static unsigned actual_stamp; |
| |
| typedef struct invariant *invariant_p; |
| |
| |
| /* The invariants. */ |
| |
| static vec<invariant_p> invariants; |
| |
| /* Check the size of the invariant table and realloc if necessary. */ |
| |
| static void |
| check_invariant_table_size (void) |
| { |
| if (invariant_table_size < DF_DEFS_TABLE_SIZE ()) |
| { |
| unsigned int new_size = DF_DEFS_TABLE_SIZE () + (DF_DEFS_TABLE_SIZE () / 4); |
| invariant_table = XRESIZEVEC (struct invariant *, invariant_table, new_size); |
| memset (&invariant_table[invariant_table_size], 0, |
| (new_size - invariant_table_size) * sizeof (struct invariant *)); |
| invariant_table_size = new_size; |
| } |
| } |
| |
| /* Test for possibility of invariantness of X. */ |
| |
| static bool |
| check_maybe_invariant (rtx x) |
| { |
| enum rtx_code code = GET_CODE (x); |
| int i, j; |
| const char *fmt; |
| |
| switch (code) |
| { |
| CASE_CONST_ANY: |
| case SYMBOL_REF: |
| case CONST: |
| case LABEL_REF: |
| return true; |
| |
| case PC: |
| case CC0: |
| case UNSPEC_VOLATILE: |
| case CALL: |
| return false; |
| |
| case REG: |
| return true; |
| |
| case MEM: |
| /* Load/store motion is done elsewhere. ??? Perhaps also add it here? |
| It should not be hard, and might be faster than "elsewhere". */ |
| |
| /* Just handle the most trivial case where we load from an unchanging |
| location (most importantly, pic tables). */ |
| if (MEM_READONLY_P (x) && !MEM_VOLATILE_P (x)) |
| break; |
| |
| return false; |
| |
| case ASM_OPERANDS: |
| /* Don't mess with insns declared volatile. */ |
| if (MEM_VOLATILE_P (x)) |
| return false; |
| break; |
| |
| default: |
| break; |
| } |
| |
| fmt = GET_RTX_FORMAT (code); |
| for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--) |
| { |
| if (fmt[i] == 'e') |
| { |
| if (!check_maybe_invariant (XEXP (x, i))) |
| return false; |
| } |
| else if (fmt[i] == 'E') |
| { |
| for (j = 0; j < XVECLEN (x, i); j++) |
| if (!check_maybe_invariant (XVECEXP (x, i, j))) |
| return false; |
| } |
| } |
| |
| return true; |
| } |
| |
| /* Returns the invariant definition for USE, or NULL if USE is not |
| invariant. */ |
| |
| static struct invariant * |
| invariant_for_use (df_ref use) |
| { |
| struct df_link *defs; |
| df_ref def; |
| basic_block bb = DF_REF_BB (use), def_bb; |
| |
| if (DF_REF_FLAGS (use) & DF_REF_READ_WRITE) |
| return NULL; |
| |
| defs = DF_REF_CHAIN (use); |
| if (!defs || defs->next) |
| return NULL; |
| def = defs->ref; |
| check_invariant_table_size (); |
| if (!invariant_table[DF_REF_ID (def)]) |
| return NULL; |
| |
| def_bb = DF_REF_BB (def); |
| if (!dominated_by_p (CDI_DOMINATORS, bb, def_bb)) |
| return NULL; |
| return invariant_table[DF_REF_ID (def)]; |
| } |
| |
| /* Computes hash value for invariant expression X in INSN. */ |
| |
| static hashval_t |
| hash_invariant_expr_1 (rtx_insn *insn, rtx x) |
| { |
| enum rtx_code code = GET_CODE (x); |
| int i, j; |
| const char *fmt; |
| hashval_t val = code; |
| int do_not_record_p; |
| df_ref use; |
| struct invariant *inv; |
| |
| switch (code) |
| { |
| CASE_CONST_ANY: |
| case SYMBOL_REF: |
| case CONST: |
| case LABEL_REF: |
| return hash_rtx (x, GET_MODE (x), &do_not_record_p, NULL, false); |
| |
| case REG: |
| use = df_find_use (insn, x); |
| if (!use) |
| return hash_rtx (x, GET_MODE (x), &do_not_record_p, NULL, false); |
| inv = invariant_for_use (use); |
| if (!inv) |
| return hash_rtx (x, GET_MODE (x), &do_not_record_p, NULL, false); |
| |
| gcc_assert (inv->eqto != ~0u); |
| return inv->eqto; |
| |
| default: |
| break; |
| } |
| |
| fmt = GET_RTX_FORMAT (code); |
| for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--) |
| { |
| if (fmt[i] == 'e') |
| val ^= hash_invariant_expr_1 (insn, XEXP (x, i)); |
| else if (fmt[i] == 'E') |
| { |
| for (j = 0; j < XVECLEN (x, i); j++) |
| val ^= hash_invariant_expr_1 (insn, XVECEXP (x, i, j)); |
| } |
| else if (fmt[i] == 'i' || fmt[i] == 'n') |
| val ^= XINT (x, i); |
| } |
| |
| return val; |
| } |
| |
| /* Returns true if the invariant expressions E1 and E2 used in insns INSN1 |
| and INSN2 have always the same value. */ |
| |
| static bool |
| invariant_expr_equal_p (rtx_insn *insn1, rtx e1, rtx_insn *insn2, rtx e2) |
| { |
| enum rtx_code code = GET_CODE (e1); |
| int i, j; |
| const char *fmt; |
| df_ref use1, use2; |
| struct invariant *inv1 = NULL, *inv2 = NULL; |
| rtx sub1, sub2; |
| |
| /* If mode of only one of the operands is VOIDmode, it is not equivalent to |
| the other one. If both are VOIDmode, we rely on the caller of this |
| function to verify that their modes are the same. */ |
| if (code != GET_CODE (e2) || GET_MODE (e1) != GET_MODE (e2)) |
| return false; |
| |
| switch (code) |
| { |
| CASE_CONST_ANY: |
| case SYMBOL_REF: |
| case CONST: |
| case LABEL_REF: |
| return rtx_equal_p (e1, e2); |
| |
| case REG: |
| use1 = df_find_use (insn1, e1); |
| use2 = df_find_use (insn2, e2); |
| if (use1) |
| inv1 = invariant_for_use (use1); |
| if (use2) |
| inv2 = invariant_for_use (use2); |
| |
| if (!inv1 && !inv2) |
| return rtx_equal_p (e1, e2); |
| |
| if (!inv1 || !inv2) |
| return false; |
| |
| gcc_assert (inv1->eqto != ~0u); |
| gcc_assert (inv2->eqto != ~0u); |
| return inv1->eqto == inv2->eqto; |
| |
| default: |
| break; |
| } |
| |
| fmt = GET_RTX_FORMAT (code); |
| for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--) |
| { |
| if (fmt[i] == 'e') |
| { |
| sub1 = XEXP (e1, i); |
| sub2 = XEXP (e2, i); |
| |
| if (!invariant_expr_equal_p (insn1, sub1, insn2, sub2)) |
| return false; |
| } |
| |
| else if (fmt[i] == 'E') |
| { |
| if (XVECLEN (e1, i) != XVECLEN (e2, i)) |
| return false; |
| |
| for (j = 0; j < XVECLEN (e1, i); j++) |
| { |
| sub1 = XVECEXP (e1, i, j); |
| sub2 = XVECEXP (e2, i, j); |
| |
| if (!invariant_expr_equal_p (insn1, sub1, insn2, sub2)) |
| return false; |
| } |
| } |
| else if (fmt[i] == 'i' || fmt[i] == 'n') |
| { |
| if (XINT (e1, i) != XINT (e2, i)) |
| return false; |
| } |
| /* Unhandled type of subexpression, we fail conservatively. */ |
| else |
| return false; |
| } |
| |
| return true; |
| } |
| |
| struct invariant_expr_hasher : typed_free_remove <invariant_expr_entry> |
| { |
| typedef invariant_expr_entry value_type; |
| typedef invariant_expr_entry compare_type; |
| static inline hashval_t hash (const value_type *); |
| static inline bool equal (const value_type *, const compare_type *); |
| }; |
| |
| /* Returns hash value for invariant expression entry ENTRY. */ |
| |
| inline hashval_t |
| invariant_expr_hasher::hash (const value_type *entry) |
| { |
| return entry->hash; |
| } |
| |
| /* Compares invariant expression entries ENTRY1 and ENTRY2. */ |
| |
| inline bool |
| invariant_expr_hasher::equal (const value_type *entry1, |
| const compare_type *entry2) |
| { |
| if (entry1->mode != entry2->mode) |
| return 0; |
| |
| return invariant_expr_equal_p (entry1->inv->insn, entry1->expr, |
| entry2->inv->insn, entry2->expr); |
| } |
| |
| typedef hash_table<invariant_expr_hasher> invariant_htab_type; |
| |
| /* Checks whether invariant with value EXPR in machine mode MODE is |
| recorded in EQ. If this is the case, return the invariant. Otherwise |
| insert INV to the table for this expression and return INV. */ |
| |
| static struct invariant * |
| find_or_insert_inv (invariant_htab_type *eq, rtx expr, machine_mode mode, |
| struct invariant *inv) |
| { |
| hashval_t hash = hash_invariant_expr_1 (inv->insn, expr); |
| struct invariant_expr_entry *entry; |
| struct invariant_expr_entry pentry; |
| invariant_expr_entry **slot; |
| |
| pentry.expr = expr; |
| pentry.inv = inv; |
| pentry.mode = mode; |
| slot = eq->find_slot_with_hash (&pentry, hash, INSERT); |
| entry = *slot; |
| |
| if (entry) |
| return entry->inv; |
| |
| entry = XNEW (struct invariant_expr_entry); |
| entry->inv = inv; |
| entry->expr = expr; |
| entry->mode = mode; |
| entry->hash = hash; |
| *slot = entry; |
| |
| return inv; |
| } |
| |
| /* Finds invariants identical to INV and records the equivalence. EQ is the |
| hash table of the invariants. */ |
| |
| static void |
| find_identical_invariants (invariant_htab_type *eq, struct invariant *inv) |
| { |
| unsigned depno; |
| bitmap_iterator bi; |
| struct invariant *dep; |
| rtx expr, set; |
| machine_mode mode; |
| struct invariant *tmp; |
| |
| if (inv->eqto != ~0u) |
| return; |
| |
| EXECUTE_IF_SET_IN_BITMAP (inv->depends_on, 0, depno, bi) |
| { |
| dep = invariants[depno]; |
| find_identical_invariants (eq, dep); |
| } |
| |
| set = single_set (inv->insn); |
| expr = SET_SRC (set); |
| mode = GET_MODE (expr); |
| if (mode == VOIDmode) |
| mode = GET_MODE (SET_DEST (set)); |
| |
| tmp = find_or_insert_inv (eq, expr, mode, inv); |
| inv->eqto = tmp->invno; |
| |
| if (tmp->invno != inv->invno && inv->always_executed) |
| tmp->eqno++; |
| |
| if (dump_file && inv->eqto != inv->invno) |
| fprintf (dump_file, |
| "Invariant %d is equivalent to invariant %d.\n", |
| inv->invno, inv->eqto); |
| } |
| |
| /* Find invariants with the same value and record the equivalences. */ |
| |
| static void |
| merge_identical_invariants (void) |
| { |
| unsigned i; |
| struct invariant *inv; |
| invariant_htab_type eq (invariants.length ()); |
| |
| FOR_EACH_VEC_ELT (invariants, i, inv) |
| find_identical_invariants (&eq, inv); |
| } |
| |
| /* Determines the basic blocks inside LOOP that are always executed and |
| stores their bitmap to ALWAYS_REACHED. MAY_EXIT is a bitmap of |
| basic blocks that may either exit the loop, or contain the call that |
| does not have to return. BODY is body of the loop obtained by |
| get_loop_body_in_dom_order. */ |
| |
| static void |
| compute_always_reached (struct loop *loop, basic_block *body, |
| bitmap may_exit, bitmap always_reached) |
| { |
| unsigned i; |
| |
| for (i = 0; i < loop->num_nodes; i++) |
| { |
| if (dominated_by_p (CDI_DOMINATORS, loop->latch, body[i])) |
| bitmap_set_bit (always_reached, i); |
| |
| if (bitmap_bit_p (may_exit, i)) |
| return; |
| } |
| } |
| |
| /* Finds exits out of the LOOP with body BODY. Marks blocks in that we may |
| exit the loop by cfg edge to HAS_EXIT and MAY_EXIT. In MAY_EXIT |
| additionally mark blocks that may exit due to a call. */ |
| |
| static void |
| find_exits (struct loop *loop, basic_block *body, |
| bitmap may_exit, bitmap has_exit) |
| { |
| unsigned i; |
| edge_iterator ei; |
| edge e; |
| struct loop *outermost_exit = loop, *aexit; |
| bool has_call = false; |
| rtx_insn *insn; |
| |
| for (i = 0; i < loop->num_nodes; i++) |
| { |
| if (body[i]->loop_father == loop) |
| { |
| FOR_BB_INSNS (body[i], insn) |
| { |
| if (CALL_P (insn) |
| && (RTL_LOOPING_CONST_OR_PURE_CALL_P (insn) |
| || !RTL_CONST_OR_PURE_CALL_P (insn))) |
| { |
| has_call = true; |
| bitmap_set_bit (may_exit, i); |
| break; |
| } |
| } |
| |
| FOR_EACH_EDGE (e, ei, body[i]->succs) |
| { |
| if (! flow_bb_inside_loop_p (loop, e->dest)) |
| { |
| bitmap_set_bit (may_exit, i); |
| bitmap_set_bit (has_exit, i); |
| outermost_exit = find_common_loop (outermost_exit, |
| e->dest->loop_father); |
| } |
| /* If we enter a subloop that might never terminate treat |
| it like a possible exit. */ |
| if (flow_loop_nested_p (loop, e->dest->loop_father)) |
| bitmap_set_bit (may_exit, i); |
| } |
| continue; |
| } |
| |
| /* Use the data stored for the subloop to decide whether we may exit |
| through it. It is sufficient to do this for header of the loop, |
| as other basic blocks inside it must be dominated by it. */ |
| if (body[i]->loop_father->header != body[i]) |
| continue; |
| |
| if (LOOP_DATA (body[i]->loop_father)->has_call) |
| { |
| has_call = true; |
| bitmap_set_bit (may_exit, i); |
| } |
| aexit = LOOP_DATA (body[i]->loop_father)->outermost_exit; |
| if (aexit != loop) |
| { |
| bitmap_set_bit (may_exit, i); |
| bitmap_set_bit (has_exit, i); |
| |
| if (flow_loop_nested_p (aexit, outermost_exit)) |
| outermost_exit = aexit; |
| } |
| } |
| |
| if (loop->aux == NULL) |
| { |
| loop->aux = xcalloc (1, sizeof (struct loop_data)); |
| bitmap_initialize (&LOOP_DATA (loop)->regs_ref, ®_obstack); |
| bitmap_initialize (&LOOP_DATA (loop)->regs_live, ®_obstack); |
| } |
| LOOP_DATA (loop)->outermost_exit = outermost_exit; |
| LOOP_DATA (loop)->has_call = has_call; |
| } |
| |
| /* Check whether we may assign a value to X from a register. */ |
| |
| static bool |
| may_assign_reg_p (rtx x) |
| { |
| return (GET_MODE (x) != VOIDmode |
| && GET_MODE (x) != BLKmode |
| && can_copy_p (GET_MODE (x)) |
| && (!REG_P (x) |
| || !HARD_REGISTER_P (x) |
| || REGNO_REG_CLASS (REGNO (x)) != NO_REGS)); |
| } |
| |
| /* Finds definitions that may correspond to invariants in LOOP with body |
| BODY. */ |
| |
| static void |
| find_defs (struct loop *loop) |
| { |
| if (dump_file) |
| { |
| fprintf (dump_file, |
| "*****starting processing of loop %d ******\n", |
| loop->num); |
| } |
| |
| df_remove_problem (df_chain); |
| df_process_deferred_rescans (); |
| df_chain_add_problem (DF_UD_CHAIN); |
| df_set_flags (DF_RD_PRUNE_DEAD_DEFS); |
| df_analyze_loop (loop); |
| check_invariant_table_size (); |
| |
| if (dump_file) |
| { |
| df_dump_region (dump_file); |
| fprintf (dump_file, |
| "*****ending processing of loop %d ******\n", |
| loop->num); |
| } |
| } |
| |
| /* Creates a new invariant for definition DEF in INSN, depending on invariants |
| in DEPENDS_ON. ALWAYS_EXECUTED is true if the insn is always executed, |
| unless the program ends due to a function call. The newly created invariant |
| is returned. */ |
| |
| static struct invariant * |
| create_new_invariant (struct def *def, rtx_insn *insn, bitmap depends_on, |
| bool always_executed) |
| { |
| struct invariant *inv = XNEW (struct invariant); |
| rtx set = single_set (insn); |
| bool speed = optimize_bb_for_speed_p (BLOCK_FOR_INSN (insn)); |
| |
| inv->def = def; |
| inv->always_executed = always_executed; |
| inv->depends_on = depends_on; |
| |
| /* If the set is simple, usually by moving it we move the whole store out of |
| the loop. Otherwise we save only cost of the computation. */ |
| if (def) |
| { |
| inv->cost = set_rtx_cost (set, speed); |
| /* ??? Try to determine cheapness of address computation. Unfortunately |
| the address cost is only a relative measure, we can't really compare |
| it with any absolute number, but only with other address costs. |
| But here we don't have any other addresses, so compare with a magic |
| number anyway. It has to be large enough to not regress PR33928 |
| (by avoiding to move reg+8,reg+16,reg+24 invariants), but small |
| enough to not regress 410.bwaves either (by still moving reg+reg |
| invariants). |
| See http://gcc.gnu.org/ml/gcc-patches/2009-10/msg01210.html . */ |
| inv->cheap_address = address_cost (SET_SRC (set), word_mode, |
| ADDR_SPACE_GENERIC, speed) < 3; |
| } |
| else |
| { |
| inv->cost = set_src_cost (SET_SRC (set), speed); |
| inv->cheap_address = false; |
| } |
| |
| inv->move = false; |
| inv->reg = NULL_RTX; |
| inv->orig_regno = -1; |
| inv->stamp = 0; |
| inv->insn = insn; |
| |
| inv->invno = invariants.length (); |
| inv->eqto = ~0u; |
| |
| /* Itself. */ |
| inv->eqno = 1; |
| |
| if (def) |
| def->invno = inv->invno; |
| invariants.safe_push (inv); |
| |
| if (dump_file) |
| { |
| fprintf (dump_file, |
| "Set in insn %d is invariant (%d), cost %d, depends on ", |
| INSN_UID (insn), inv->invno, inv->cost); |
| dump_bitmap (dump_file, inv->depends_on); |
| } |
| |
| return inv; |
| } |
| |
| /* Record USE at DEF. */ |
| |
| static void |
| record_use (struct def *def, df_ref use) |
| { |
| struct use *u = XNEW (struct use); |
| |
| u->pos = DF_REF_REAL_LOC (use); |
| u->insn = DF_REF_INSN (use); |
| u->addr_use_p = (DF_REF_TYPE (use) == DF_REF_REG_MEM_LOAD |
| || DF_REF_TYPE (use) == DF_REF_REG_MEM_STORE); |
| u->next = def->uses; |
| def->uses = u; |
| def->n_uses++; |
| if (u->addr_use_p) |
| def->n_addr_uses++; |
| } |
| |
| /* Finds the invariants USE depends on and store them to the DEPENDS_ON |
| bitmap. Returns true if all dependencies of USE are known to be |
| loop invariants, false otherwise. */ |
| |
| static bool |
| check_dependency (basic_block bb, df_ref use, bitmap depends_on) |
| { |
| df_ref def; |
| basic_block def_bb; |
| struct df_link *defs; |
| struct def *def_data; |
| struct invariant *inv; |
| |
| if (DF_REF_FLAGS (use) & DF_REF_READ_WRITE) |
| return false; |
| |
| defs = DF_REF_CHAIN (use); |
| if (!defs) |
| { |
| unsigned int regno = DF_REF_REGNO (use); |
| |
| /* If this is the use of an uninitialized argument register that is |
| likely to be spilled, do not move it lest this might extend its |
| lifetime and cause reload to die. This can occur for a call to |
| a function taking complex number arguments and moving the insns |
| preparing the arguments without moving the call itself wouldn't |
| gain much in practice. */ |
| if ((DF_REF_FLAGS (use) & DF_HARD_REG_LIVE) |
| && FUNCTION_ARG_REGNO_P (regno) |
| && targetm.class_likely_spilled_p (REGNO_REG_CLASS (regno))) |
| return false; |
| |
| return true; |
| } |
| |
| if (defs->next) |
| return false; |
| |
| def = defs->ref; |
| check_invariant_table_size (); |
| inv = invariant_table[DF_REF_ID (def)]; |
| if (!inv) |
| return false; |
| |
| def_data = inv->def; |
| gcc_assert (def_data != NULL); |
| |
| def_bb = DF_REF_BB (def); |
| /* Note that in case bb == def_bb, we know that the definition |
| dominates insn, because def has invariant_table[DF_REF_ID(def)] |
| defined and we process the insns in the basic block bb |
| sequentially. */ |
| if (!dominated_by_p (CDI_DOMINATORS, bb, def_bb)) |
| return false; |
| |
| bitmap_set_bit (depends_on, def_data->invno); |
| return true; |
| } |
| |
| |
| /* Finds the invariants INSN depends on and store them to the DEPENDS_ON |
| bitmap. Returns true if all dependencies of INSN are known to be |
| loop invariants, false otherwise. */ |
| |
| static bool |
| check_dependencies (rtx_insn *insn, bitmap depends_on) |
| { |
| struct df_insn_info *insn_info = DF_INSN_INFO_GET (insn); |
| df_ref use; |
| basic_block bb = BLOCK_FOR_INSN (insn); |
| |
| FOR_EACH_INSN_INFO_USE (use, insn_info) |
| if (!check_dependency (bb, use, depends_on)) |
| return false; |
| FOR_EACH_INSN_INFO_EQ_USE (use, insn_info) |
| if (!check_dependency (bb, use, depends_on)) |
| return false; |
| |
| return true; |
| } |
| |
| /* Pre-check candidate DEST to skip the one which can not make a valid insn |
| during move_invariant_reg. SIMPLE is to skip HARD_REGISTER. */ |
| static bool |
| pre_check_invariant_p (bool simple, rtx dest) |
| { |
| if (simple && REG_P (dest) && DF_REG_DEF_COUNT (REGNO (dest)) > 1) |
| { |
| df_ref use; |
| rtx ref; |
| unsigned int i = REGNO (dest); |
| struct df_insn_info *insn_info; |
| df_ref def_rec; |
| |
| for (use = DF_REG_USE_CHAIN (i); use; use = DF_REF_NEXT_REG (use)) |
| { |
| ref = DF_REF_INSN (use); |
| insn_info = DF_INSN_INFO_GET (ref); |
| |
| FOR_EACH_INSN_INFO_DEF (def_rec, insn_info) |
| if (DF_REF_REGNO (def_rec) == i) |
| { |
| /* Multi definitions at this stage, most likely are due to |
| instruction constraints, which requires both read and write |
| on the same register. Since move_invariant_reg is not |
| powerful enough to handle such cases, just ignore the INV |
| and leave the chance to others. */ |
| return false; |
| } |
| } |
| } |
| return true; |
| } |
| |
| /* Finds invariant in INSN. ALWAYS_REACHED is true if the insn is always |
| executed. ALWAYS_EXECUTED is true if the insn is always executed, |
| unless the program ends due to a function call. */ |
| |
| static void |
| find_invariant_insn (rtx_insn *insn, bool, bool always_executed) |
| { |
| df_ref ref; |
| struct def *def; |
| bitmap depends_on; |
| rtx set, dest; |
| bool simple = true; |
| struct invariant *inv; |
| |
| #ifdef HAVE_cc0 |
| /* We can't move a CC0 setter without the user. */ |
| if (sets_cc0_p (insn)) |
| return; |
| #endif |
| |
| set = single_set (insn); |
| if (!set) |
| return; |
| dest = SET_DEST (set); |
| |
| if (!REG_P (dest) |
| || HARD_REGISTER_P (dest)) |
| simple = false; |
| |
| if (!may_assign_reg_p (dest) |
| || !pre_check_invariant_p (simple, dest) |
| || !check_maybe_invariant (SET_SRC (set))) |
| return; |
| |
| /* If the insn can throw exception, we cannot move it at all without changing |
| cfg. */ |
| if (can_throw_internal (insn)) |
| return; |
| |
| /* We cannot make trapping insn executed. */ |
| if (may_trap_or_fault_p (PATTERN (insn))) |
| return; |
| |
| depends_on = BITMAP_ALLOC (NULL); |
| if (!check_dependencies (insn, depends_on)) |
| { |
| BITMAP_FREE (depends_on); |
| return; |
| } |
| |
| if (simple) |
| def = XCNEW (struct def); |
| else |
| def = NULL; |
| |
| inv = create_new_invariant (def, insn, depends_on, always_executed); |
| |
| if (simple) |
| { |
| ref = df_find_def (insn, dest); |
| check_invariant_table_size (); |
| invariant_table[DF_REF_ID (ref)] = inv; |
| } |
| } |
| |
| /* Record registers used in INSN that have a unique invariant definition. */ |
| |
| static void |
| record_uses (rtx_insn *insn) |
| { |
| struct df_insn_info *insn_info = DF_INSN_INFO_GET (insn); |
| df_ref use; |
| struct invariant *inv; |
| |
| FOR_EACH_INSN_INFO_USE (use, insn_info) |
| { |
| inv = invariant_for_use (use); |
| if (inv) |
| record_use (inv->def, use); |
| } |
| FOR_EACH_INSN_INFO_EQ_USE (use, insn_info) |
| { |
| inv = invariant_for_use (use); |
| if (inv) |
| record_use (inv->def, use); |
| } |
| } |
| |
| /* Finds invariants in INSN. ALWAYS_REACHED is true if the insn is always |
| executed. ALWAYS_EXECUTED is true if the insn is always executed, |
| unless the program ends due to a function call. */ |
| |
| static void |
| find_invariants_insn (rtx_insn *insn, bool always_reached, bool always_executed) |
| { |
| find_invariant_insn (insn, always_reached, always_executed); |
| record_uses (insn); |
| } |
| |
| /* Finds invariants in basic block BB. ALWAYS_REACHED is true if the |
| basic block is always executed. ALWAYS_EXECUTED is true if the basic |
| block is always executed, unless the program ends due to a function |
| call. */ |
| |
| static void |
| find_invariants_bb (basic_block bb, bool always_reached, bool always_executed) |
| { |
| rtx_insn *insn; |
| |
| FOR_BB_INSNS (bb, insn) |
| { |
| if (!NONDEBUG_INSN_P (insn)) |
| continue; |
| |
| find_invariants_insn (insn, always_reached, always_executed); |
| |
| if (always_reached |
| && CALL_P (insn) |
| && (RTL_LOOPING_CONST_OR_PURE_CALL_P (insn) |
| || ! RTL_CONST_OR_PURE_CALL_P (insn))) |
| always_reached = false; |
| } |
| } |
| |
| /* Finds invariants in LOOP with body BODY. ALWAYS_REACHED is the bitmap of |
| basic blocks in BODY that are always executed. ALWAYS_EXECUTED is the |
| bitmap of basic blocks in BODY that are always executed unless the program |
| ends due to a function call. */ |
| |
| static void |
| find_invariants_body (struct loop *loop, basic_block *body, |
| bitmap always_reached, bitmap always_executed) |
| { |
| unsigned i; |
| |
| for (i = 0; i < loop->num_nodes; i++) |
| find_invariants_bb (body[i], |
| bitmap_bit_p (always_reached, i), |
| bitmap_bit_p (always_executed, i)); |
| } |
| |
| /* Finds invariants in LOOP. */ |
| |
| static void |
| find_invariants (struct loop *loop) |
| { |
| bitmap may_exit = BITMAP_ALLOC (NULL); |
| bitmap always_reached = BITMAP_ALLOC (NULL); |
| bitmap has_exit = BITMAP_ALLOC (NULL); |
| bitmap always_executed = BITMAP_ALLOC (NULL); |
| basic_block *body = get_loop_body_in_dom_order (loop); |
| |
| find_exits (loop, body, may_exit, has_exit); |
| compute_always_reached (loop, body, may_exit, always_reached); |
| compute_always_reached (loop, body, has_exit, always_executed); |
| |
| find_defs (loop); |
| find_invariants_body (loop, body, always_reached, always_executed); |
| merge_identical_invariants (); |
| |
| BITMAP_FREE (always_reached); |
| BITMAP_FREE (always_executed); |
| BITMAP_FREE (may_exit); |
| BITMAP_FREE (has_exit); |
| free (body); |
| } |
| |
| /* Frees a list of uses USE. */ |
| |
| static void |
| free_use_list (struct use *use) |
| { |
| struct use *next; |
| |
| for (; use; use = next) |
| { |
| next = use->next; |
| free (use); |
| } |
| } |
| |
| /* Return pressure class and number of hard registers (through *NREGS) |
| for destination of INSN. */ |
| static enum reg_class |
| get_pressure_class_and_nregs (rtx_insn *insn, int *nregs) |
| { |
| rtx reg; |
| enum reg_class pressure_class; |
| rtx set = single_set (insn); |
| |
| /* Considered invariant insns have only one set. */ |
| gcc_assert (set != NULL_RTX); |
| reg = SET_DEST (set); |
| if (GET_CODE (reg) == SUBREG) |
| reg = SUBREG_REG (reg); |
| if (MEM_P (reg)) |
| { |
| *nregs = 0; |
| pressure_class = NO_REGS; |
| } |
| else |
| { |
| if (! REG_P (reg)) |
| reg = NULL_RTX; |
| if (reg == NULL_RTX) |
| pressure_class = GENERAL_REGS; |
| else |
| { |
| pressure_class = reg_allocno_class (REGNO (reg)); |
| pressure_class = ira_pressure_class_translate[pressure_class]; |
| } |
| *nregs |
| = ira_reg_class_max_nregs[pressure_class][GET_MODE (SET_SRC (set))]; |
| } |
| return pressure_class; |
| } |
| |
| /* Calculates cost and number of registers needed for moving invariant INV |
| out of the loop and stores them to *COST and *REGS_NEEDED. *CL will be |
| the REG_CLASS of INV. Return |
| -1: if INV is invalid. |
| 0: if INV and its depends_on have same reg_class |
| 1: if INV and its depends_on have different reg_classes. */ |
| |
| static int |
| get_inv_cost (struct invariant *inv, int *comp_cost, unsigned *regs_needed, |
| enum reg_class *cl) |
| { |
| int i, acomp_cost; |
| unsigned aregs_needed[N_REG_CLASSES]; |
| unsigned depno; |
| struct invariant *dep; |
| bitmap_iterator bi; |
| int ret = 1; |
| |
| /* Find the representative of the class of the equivalent invariants. */ |
| inv = invariants[inv->eqto]; |
| |
| *comp_cost = 0; |
| if (! flag_ira_loop_pressure) |
| regs_needed[0] = 0; |
| else |
| { |
| for (i = 0; i < ira_pressure_classes_num; i++) |
| regs_needed[ira_pressure_classes[i]] = 0; |
| } |
| |
| if (inv->move |
| || inv->stamp == actual_stamp) |
| return -1; |
| inv->stamp = actual_stamp; |
| |
| if (! flag_ira_loop_pressure) |
| regs_needed[0]++; |
| else |
| { |
| int nregs; |
| enum reg_class pressure_class; |
| |
| pressure_class = get_pressure_class_and_nregs (inv->insn, &nregs); |
| regs_needed[pressure_class] += nregs; |
| *cl = pressure_class; |
| ret = 0; |
| } |
| |
| if (!inv->cheap_address |
| || inv->def->n_addr_uses < inv->def->n_uses) |
| (*comp_cost) += inv->cost * inv->eqno; |
| |
| #ifdef STACK_REGS |
| { |
| /* Hoisting constant pool constants into stack regs may cost more than |
| just single register. On x87, the balance is affected both by the |
| small number of FP registers, and by its register stack organization, |
| that forces us to add compensation code in and around the loop to |
| shuffle the operands to the top of stack before use, and pop them |
| from the stack after the loop finishes. |
| |
| To model this effect, we increase the number of registers needed for |
| stack registers by two: one register push, and one register pop. |
| This usually has the effect that FP constant loads from the constant |
| pool are not moved out of the loop. |
| |
| Note that this also means that dependent invariants can not be moved. |
| However, the primary purpose of this pass is to move loop invariant |
| address arithmetic out of loops, and address arithmetic that depends |
| on floating point constants is unlikely to ever occur. */ |
| rtx set = single_set (inv->insn); |
| if (set |
| && IS_STACK_MODE (GET_MODE (SET_SRC (set))) |
| && constant_pool_constant_p (SET_SRC (set))) |
| { |
| if (flag_ira_loop_pressure) |
| regs_needed[ira_stack_reg_pressure_class] += 2; |
| else |
| regs_needed[0] += 2; |
| } |
| } |
| #endif |
| |
| EXECUTE_IF_SET_IN_BITMAP (inv->depends_on, 0, depno, bi) |
| { |
| bool check_p; |
| enum reg_class dep_cl = ALL_REGS; |
| int dep_ret; |
| |
| dep = invariants[depno]; |
| |
| /* If DEP is moved out of the loop, it is not a depends_on any more. */ |
| if (dep->move) |
| continue; |
| |
| dep_ret = get_inv_cost (dep, &acomp_cost, aregs_needed, &dep_cl); |
| |
| if (! flag_ira_loop_pressure) |
| check_p = aregs_needed[0] != 0; |
| else |
| { |
| for (i = 0; i < ira_pressure_classes_num; i++) |
| if (aregs_needed[ira_pressure_classes[i]] != 0) |
| break; |
| check_p = i < ira_pressure_classes_num; |
| |
| if ((dep_ret == 1) || ((dep_ret == 0) && (*cl != dep_cl))) |
| { |
| *cl = ALL_REGS; |
| ret = 1; |
| } |
| } |
| if (check_p |
| /* We need to check always_executed, since if the original value of |
| the invariant may be preserved, we may need to keep it in a |
| separate register. TODO check whether the register has an |
| use outside of the loop. */ |
| && dep->always_executed |
| && !dep->def->uses->next) |
| { |
| /* If this is a single use, after moving the dependency we will not |
| need a new register. */ |
| if (! flag_ira_loop_pressure) |
| aregs_needed[0]--; |
| else |
| { |
| int nregs; |
| enum reg_class pressure_class; |
| |
| pressure_class = get_pressure_class_and_nregs (inv->insn, &nregs); |
| aregs_needed[pressure_class] -= nregs; |
| } |
| } |
| |
| if (! flag_ira_loop_pressure) |
| regs_needed[0] += aregs_needed[0]; |
| else |
| { |
| for (i = 0; i < ira_pressure_classes_num; i++) |
| regs_needed[ira_pressure_classes[i]] |
| += aregs_needed[ira_pressure_classes[i]]; |
| } |
| (*comp_cost) += acomp_cost; |
| } |
| return ret; |
| } |
| |
| /* Calculates gain for eliminating invariant INV. REGS_USED is the number |
| of registers used in the loop, NEW_REGS is the number of new variables |
| already added due to the invariant motion. The number of registers needed |
| for it is stored in *REGS_NEEDED. SPEED and CALL_P are flags passed |
| through to estimate_reg_pressure_cost. */ |
| |
| static int |
| gain_for_invariant (struct invariant *inv, unsigned *regs_needed, |
| unsigned *new_regs, unsigned regs_used, |
| bool speed, bool call_p) |
| { |
| int comp_cost, size_cost; |
| /* Workaround -Wmaybe-uninitialized false positive during |
| profiledbootstrap by initializing it. */ |
| enum reg_class cl = NO_REGS; |
| int ret; |
| |
| actual_stamp++; |
| |
| ret = get_inv_cost (inv, &comp_cost, regs_needed, &cl); |
| |
| if (! flag_ira_loop_pressure) |
| { |
| size_cost = (estimate_reg_pressure_cost (new_regs[0] + regs_needed[0], |
| regs_used, speed, call_p) |
| - estimate_reg_pressure_cost (new_regs[0], |
| regs_used, speed, call_p)); |
| } |
| else if (ret < 0) |
| return -1; |
| else if ((ret == 0) && (cl == NO_REGS)) |
| /* Hoist it anyway since it does not impact register pressure. */ |
| return 1; |
| else |
| { |
| int i; |
| enum reg_class pressure_class; |
| |
| for (i = 0; i < ira_pressure_classes_num; i++) |
| { |
| pressure_class = ira_pressure_classes[i]; |
| |
| if (!reg_classes_intersect_p (pressure_class, cl)) |
| continue; |
| |
| if ((int) new_regs[pressure_class] |
| + (int) regs_needed[pressure_class] |
| + LOOP_DATA (curr_loop)->max_reg_pressure[pressure_class] |
| + IRA_LOOP_RESERVED_REGS |
| > ira_class_hard_regs_num[pressure_class]) |
| break; |
| } |
| if (i < ira_pressure_classes_num) |
| /* There will be register pressure excess and we want not to |
| make this loop invariant motion. All loop invariants with |
| non-positive gains will be rejected in function |
| find_invariants_to_move. Therefore we return the negative |
| number here. |
| |
| One could think that this rejects also expensive loop |
| invariant motions and this will hurt code performance. |
| However numerous experiments with different heuristics |
| taking invariant cost into account did not confirm this |
| assumption. There are possible explanations for this |
| result: |
| o probably all expensive invariants were already moved out |
| of the loop by PRE and gimple invariant motion pass. |
| o expensive invariant execution will be hidden by insn |
| scheduling or OOO processor hardware because usually such |
| invariants have a lot of freedom to be executed |
| out-of-order. |
| Another reason for ignoring invariant cost vs spilling cost |
| heuristics is also in difficulties to evaluate accurately |
| spill cost at this stage. */ |
| return -1; |
| else |
| size_cost = 0; |
| } |
| |
| return comp_cost - size_cost; |
| } |
| |
| /* Finds invariant with best gain for moving. Returns the gain, stores |
| the invariant in *BEST and number of registers needed for it to |
| *REGS_NEEDED. REGS_USED is the number of registers used in the loop. |
| NEW_REGS is the number of new variables already added due to invariant |
| motion. */ |
| |
| static int |
| best_gain_for_invariant (struct invariant **best, unsigned *regs_needed, |
| unsigned *new_regs, unsigned regs_used, |
| bool speed, bool call_p) |
| { |
| struct invariant *inv; |
| int i, gain = 0, again; |
| unsigned aregs_needed[N_REG_CLASSES], invno; |
| |
| FOR_EACH_VEC_ELT (invariants, invno, inv) |
| { |
| if (inv->move) |
| continue; |
| |
| /* Only consider the "representatives" of equivalent invariants. */ |
| if (inv->eqto != inv->invno) |
| continue; |
| |
| again = gain_for_invariant (inv, aregs_needed, new_regs, regs_used, |
| speed, call_p); |
| if (again > gain) |
| { |
| gain = again; |
| *best = inv; |
| if (! flag_ira_loop_pressure) |
| regs_needed[0] = aregs_needed[0]; |
| else |
| { |
| for (i = 0; i < ira_pressure_classes_num; i++) |
| regs_needed[ira_pressure_classes[i]] |
| = aregs_needed[ira_pressure_classes[i]]; |
| } |
| } |
| } |
| |
| return gain; |
| } |
| |
| /* Marks invariant INVNO and all its dependencies for moving. */ |
| |
| static void |
| set_move_mark (unsigned invno, int gain) |
| { |
| struct invariant *inv = invariants[invno]; |
| bitmap_iterator bi; |
| |
| /* Find the representative of the class of the equivalent invariants. */ |
| inv = invariants[inv->eqto]; |
| |
| if (inv->move) |
| return; |
| inv->move = true; |
| |
| if (dump_file) |
| { |
| if (gain >= 0) |
| fprintf (dump_file, "Decided to move invariant %d -- gain %d\n", |
| invno, gain); |
| else |
| fprintf (dump_file, "Decided to move dependent invariant %d\n", |
| invno); |
| }; |
| |
| EXECUTE_IF_SET_IN_BITMAP (inv->depends_on, 0, invno, bi) |
| { |
| set_move_mark (invno, -1); |
| } |
| } |
| |
| /* Determines which invariants to move. */ |
| |
| static void |
| find_invariants_to_move (bool speed, bool call_p) |
| { |
| int gain; |
| unsigned i, regs_used, regs_needed[N_REG_CLASSES], new_regs[N_REG_CLASSES]; |
| struct invariant *inv = NULL; |
| |
| if (!invariants.length ()) |
| return; |
| |
| if (flag_ira_loop_pressure) |
| /* REGS_USED is actually never used when the flag is on. */ |
| regs_used = 0; |
| else |
| /* We do not really do a good job in estimating number of |
| registers used; we put some initial bound here to stand for |
| induction variables etc. that we do not detect. */ |
| { |
| unsigned int n_regs = DF_REG_SIZE (df); |
| |
| regs_used = 2; |
| |
| for (i = 0; i < n_regs; i++) |
| { |
| if (!DF_REGNO_FIRST_DEF (i) && DF_REGNO_LAST_USE (i)) |
| { |
| /* This is a value that is used but not changed inside loop. */ |
| regs_used++; |
| } |
| } |
| } |
| |
| if (! flag_ira_loop_pressure) |
| new_regs[0] = regs_needed[0] = 0; |
| else |
| { |
| for (i = 0; (int) i < ira_pressure_classes_num; i++) |
| new_regs[ira_pressure_classes[i]] = 0; |
| } |
| while ((gain = best_gain_for_invariant (&inv, regs_needed, |
| new_regs, regs_used, |
| speed, call_p)) > 0) |
| { |
| set_move_mark (inv->invno, gain); |
| if (! flag_ira_loop_pressure) |
| new_regs[0] += regs_needed[0]; |
| else |
| { |
| for (i = 0; (int) i < ira_pressure_classes_num; i++) |
| new_regs[ira_pressure_classes[i]] |
| += regs_needed[ira_pressure_classes[i]]; |
| } |
| } |
| } |
| |
| /* Replace the uses, reached by the definition of invariant INV, by REG. |
| |
| IN_GROUP is nonzero if this is part of a group of changes that must be |
| performed as a group. In that case, the changes will be stored. The |
| function `apply_change_group' will validate and apply the changes. */ |
| |
| static int |
| replace_uses (struct invariant *inv, rtx reg, bool in_group) |
| { |
| /* Replace the uses we know to be dominated. It saves work for copy |
| propagation, and also it is necessary so that dependent invariants |
| are computed right. */ |
| if (inv->def) |
| { |
| struct use *use; |
| for (use = inv->def->uses; use; use = use->next) |
| validate_change (use->insn, use->pos, reg, true); |
| |
| /* If we aren't part of a larger group, apply the changes now. */ |
| if (!in_group) |
| return apply_change_group (); |
| } |
| |
| return 1; |
| } |
| |
| /* Move invariant INVNO out of the LOOP. Returns true if this succeeds, false |
| otherwise. */ |
| |
| static bool |
| move_invariant_reg (struct loop *loop, unsigned invno) |
| { |
| struct invariant *inv = invariants[invno]; |
| struct invariant *repr = invariants[inv->eqto]; |
| unsigned i; |
| basic_block preheader = loop_preheader_edge (loop)->src; |
| rtx reg, set, dest, note; |
| bitmap_iterator bi; |
| int regno = -1; |
| |
| if (inv->reg) |
| return true; |
| if (!repr->move) |
| return false; |
| |
| /* If this is a representative of the class of equivalent invariants, |
| really move the invariant. Otherwise just replace its use with |
| the register used for the representative. */ |
| if (inv == repr) |
| { |
| if (inv->depends_on) |
| { |
| EXECUTE_IF_SET_IN_BITMAP (inv->depends_on, 0, i, bi) |
| { |
| if (!move_invariant_reg (loop, i)) |
| goto fail; |
| } |
| } |
| |
| /* Move the set out of the loop. If the set is always executed (we could |
| omit this condition if we know that the register is unused outside of |
| the loop, but it does not seem worth finding out) and it has no uses |
| that would not be dominated by it, we may just move it (TODO). |
| Otherwise we need to create a temporary register. */ |
| set = single_set (inv->insn); |
| reg = dest = SET_DEST (set); |
| if (GET_CODE (reg) == SUBREG) |
| reg = SUBREG_REG (reg); |
| if (REG_P (reg)) |
| regno = REGNO (reg); |
| |
| reg = gen_reg_rtx_and_attrs (dest); |
| |
| /* Try replacing the destination by a new pseudoregister. */ |
| validate_change (inv->insn, &SET_DEST (set), reg, true); |
| |
| /* As well as all the dominated uses. */ |
| replace_uses (inv, reg, true); |
| |
| /* And validate all the changes. */ |
| if (!apply_change_group ()) |
| goto fail; |
| |
| emit_insn_after (gen_move_insn (dest, reg), inv->insn); |
| reorder_insns (inv->insn, inv->insn, BB_END (preheader)); |
| |
| /* If there is a REG_EQUAL note on the insn we just moved, and the |
| insn is in a basic block that is not always executed or the note |
| contains something for which we don't know the invariant status, |
| the note may no longer be valid after we move the insn. Note that |
| uses in REG_EQUAL notes are taken into account in the computation |
| of invariants, so it is safe to retain the note even if it contains |
| register references for which we know the invariant status. */ |
| if ((note = find_reg_note (inv->insn, REG_EQUAL, NULL_RTX)) |
| && (!inv->always_executed |
| || !check_maybe_invariant (XEXP (note, 0)))) |
| remove_note (inv->insn, note); |
| } |
| else |
| { |
| if (!move_invariant_reg (loop, repr->invno)) |
| goto fail; |
| reg = repr->reg; |
| regno = repr->orig_regno; |
| if (!replace_uses (inv, reg, false)) |
| goto fail; |
| set = single_set (inv->insn); |
| emit_insn_after (gen_move_insn (SET_DEST (set), reg), inv->insn); |
| delete_insn (inv->insn); |
| } |
| |
| inv->reg = reg; |
| inv->orig_regno = regno; |
| |
| return true; |
| |
| fail: |
| /* If we failed, clear move flag, so that we do not try to move inv |
| again. */ |
| if (dump_file) |
| fprintf (dump_file, "Failed to move invariant %d\n", invno); |
| inv->move = false; |
| inv->reg = NULL_RTX; |
| inv->orig_regno = -1; |
| |
| return false; |
| } |
| |
| /* Move selected invariant out of the LOOP. Newly created regs are marked |
| in TEMPORARY_REGS. */ |
| |
| static void |
| move_invariants (struct loop *loop) |
| { |
| struct invariant *inv; |
| unsigned i; |
| |
| FOR_EACH_VEC_ELT (invariants, i, inv) |
| move_invariant_reg (loop, i); |
| if (flag_ira_loop_pressure && resize_reg_info ()) |
| { |
| FOR_EACH_VEC_ELT (invariants, i, inv) |
| if (inv->reg != NULL_RTX) |
| { |
| if (inv->orig_regno >= 0) |
| setup_reg_classes (REGNO (inv->reg), |
| reg_preferred_class (inv->orig_regno), |
| reg_alternate_class (inv->orig_regno), |
| reg_allocno_class (inv->orig_regno)); |
| else |
| setup_reg_classes (REGNO (inv->reg), |
| GENERAL_REGS, NO_REGS, GENERAL_REGS); |
| } |
| } |
| } |
| |
| /* Initializes invariant motion data. */ |
| |
| static void |
| init_inv_motion_data (void) |
| { |
| actual_stamp = 1; |
| |
| invariants.create (100); |
| } |
| |
| /* Frees the data allocated by invariant motion. */ |
| |
| static void |
| free_inv_motion_data (void) |
| { |
| unsigned i; |
| struct def *def; |
| struct invariant *inv; |
| |
| check_invariant_table_size (); |
| for (i = 0; i < DF_DEFS_TABLE_SIZE (); i++) |
| { |
| inv = invariant_table[i]; |
| if (inv) |
| { |
| def = inv->def; |
| gcc_assert (def != NULL); |
| |
| free_use_list (def->uses); |
| free (def); |
| invariant_table[i] = NULL; |
| } |
| } |
| |
| FOR_EACH_VEC_ELT (invariants, i, inv) |
| { |
| BITMAP_FREE (inv->depends_on); |
| free (inv); |
| } |
| invariants.release (); |
| } |
| |
| /* Move the invariants out of the LOOP. */ |
| |
| static void |
| move_single_loop_invariants (struct loop *loop) |
| { |
| init_inv_motion_data (); |
| |
| find_invariants (loop); |
| find_invariants_to_move (optimize_loop_for_speed_p (loop), |
| LOOP_DATA (loop)->has_call); |
| move_invariants (loop); |
| |
| free_inv_motion_data (); |
| } |
| |
| /* Releases the auxiliary data for LOOP. */ |
| |
| static void |
| free_loop_data (struct loop *loop) |
| { |
| struct loop_data *data = LOOP_DATA (loop); |
| if (!data) |
| return; |
| |
| bitmap_clear (&LOOP_DATA (loop)->regs_ref); |
| bitmap_clear (&LOOP_DATA (loop)->regs_live); |
| free (data); |
| loop->aux = NULL; |
| } |
| |
| |
| |
| /* Registers currently living. */ |
| static bitmap_head curr_regs_live; |
| |
| /* Current reg pressure for each pressure class. */ |
| static int curr_reg_pressure[N_REG_CLASSES]; |
| |
| /* Record all regs that are set in any one insn. Communication from |
| mark_reg_{store,clobber} and global_conflicts. Asm can refer to |
| all hard-registers. */ |
| static rtx regs_set[(FIRST_PSEUDO_REGISTER > MAX_RECOG_OPERANDS |
| ? FIRST_PSEUDO_REGISTER : MAX_RECOG_OPERANDS) * 2]; |
| /* Number of regs stored in the previous array. */ |
| static int n_regs_set; |
| |
| /* Return pressure class and number of needed hard registers (through |
| *NREGS) of register REGNO. */ |
| static enum reg_class |
| get_regno_pressure_class (int regno, int *nregs) |
| { |
| if (regno >= FIRST_PSEUDO_REGISTER) |
| { |
| enum reg_class pressure_class; |
| |
| pressure_class = reg_allocno_class (regno); |
| pressure_class = ira_pressure_class_translate[pressure_class]; |
| *nregs |
| = ira_reg_class_max_nregs[pressure_class][PSEUDO_REGNO_MODE (regno)]; |
| return pressure_class; |
| } |
| else if (! TEST_HARD_REG_BIT (ira_no_alloc_regs, regno) |
| && ! TEST_HARD_REG_BIT (eliminable_regset, regno)) |
| { |
| *nregs = 1; |
| return ira_pressure_class_translate[REGNO_REG_CLASS (regno)]; |
| } |
| else |
| { |
| *nregs = 0; |
| return NO_REGS; |
| } |
| } |
| |
| /* Increase (if INCR_P) or decrease current register pressure for |
| register REGNO. */ |
| static void |
| change_pressure (int regno, bool incr_p) |
| { |
| int nregs; |
| enum reg_class pressure_class; |
| |
| pressure_class = get_regno_pressure_class (regno, &nregs); |
| if (! incr_p) |
| curr_reg_pressure[pressure_class] -= nregs; |
| else |
| { |
| curr_reg_pressure[pressure_class] += nregs; |
| if (LOOP_DATA (curr_loop)->max_reg_pressure[pressure_class] |
| < curr_reg_pressure[pressure_class]) |
| LOOP_DATA (curr_loop)->max_reg_pressure[pressure_class] |
| = curr_reg_pressure[pressure_class]; |
| } |
| } |
| |
| /* Mark REGNO birth. */ |
| static void |
| mark_regno_live (int regno) |
| { |
| struct loop *loop; |
| |
| for (loop = curr_loop; |
| loop != current_loops->tree_root; |
| loop = loop_outer (loop)) |
| bitmap_set_bit (&LOOP_DATA (loop)->regs_live, regno); |
| if (!bitmap_set_bit (&curr_regs_live, regno)) |
| return; |
| change_pressure (regno, true); |
| } |
| |
| /* Mark REGNO death. */ |
| static void |
| mark_regno_death (int regno) |
| { |
| if (! bitmap_clear_bit (&curr_regs_live, regno)) |
| return; |
| change_pressure (regno, false); |
| } |
| |
| /* Mark setting register REG. */ |
| static void |
| mark_reg_store (rtx reg, const_rtx setter ATTRIBUTE_UNUSED, |
| void *data ATTRIBUTE_UNUSED) |
| { |
| int regno; |
| |
| if (GET_CODE (reg) == SUBREG) |
| reg = SUBREG_REG (reg); |
| |
| if (! REG_P (reg)) |
| return; |
| |
| regs_set[n_regs_set++] = reg; |
| |
| regno = REGNO (reg); |
| |
| if (regno >= FIRST_PSEUDO_REGISTER) |
| mark_regno_live (regno); |
| else |
| { |
| int last = regno + hard_regno_nregs[regno][GET_MODE (reg)]; |
| |
| while (regno < last) |
| { |
| mark_regno_live (regno); |
| regno++; |
| } |
| } |
| } |
| |
| /* Mark clobbering register REG. */ |
| static void |
| mark_reg_clobber (rtx reg, const_rtx setter, void *data) |
| { |
| if (GET_CODE (setter) == CLOBBER) |
| mark_reg_store (reg, setter, data); |
| } |
| |
| /* Mark register REG death. */ |
| static void |
| mark_reg_death (rtx reg) |
| { |
| int regno = REGNO (reg); |
| |
| if (regno >= FIRST_PSEUDO_REGISTER) |
| mark_regno_death (regno); |
| else |
| { |
| int last = regno + hard_regno_nregs[regno][GET_MODE (reg)]; |
| |
| while (regno < last) |
| { |
| mark_regno_death (regno); |
| regno++; |
| } |
| } |
| } |
| |
| /* Mark occurrence of registers in X for the current loop. */ |
| static void |
| mark_ref_regs (rtx x) |
| { |
| RTX_CODE code; |
| int i; |
| const char *fmt; |
| |
| if (!x) |
| return; |
| |
| code = GET_CODE (x); |
| if (code == REG) |
| { |
| struct loop *loop; |
| |
| for (loop = curr_loop; |
| loop != current_loops->tree_root; |
| loop = loop_outer (loop)) |
| bitmap_set_bit (&LOOP_DATA (loop)->regs_ref, REGNO (x)); |
| return; |
| } |
| |
| fmt = GET_RTX_FORMAT (code); |
| for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--) |
| if (fmt[i] == 'e') |
| mark_ref_regs (XEXP (x, i)); |
| else if (fmt[i] == 'E') |
| { |
| int j; |
| |
| for (j = 0; j < XVECLEN (x, i); j++) |
| mark_ref_regs (XVECEXP (x, i, j)); |
| } |
| } |
| |
| /* Calculate register pressure in the loops. */ |
| static void |
| calculate_loop_reg_pressure (void) |
| { |
| int i; |
| unsigned int j; |
| bitmap_iterator bi; |
| basic_block bb; |
| rtx_insn *insn; |
| rtx link; |
| struct loop *loop, *parent; |
| |
| FOR_EACH_LOOP (loop, 0) |
| if (loop->aux == NULL) |
| { |
| loop->aux = xcalloc (1, sizeof (struct loop_data)); |
| bitmap_initialize (&LOOP_DATA (loop)->regs_ref, ®_obstack); |
| bitmap_initialize (&LOOP_DATA (loop)->regs_live, ®_obstack); |
| } |
| ira_setup_eliminable_regset (); |
| bitmap_initialize (&curr_regs_live, ®_obstack); |
| FOR_EACH_BB_FN (bb, cfun) |
| { |
| curr_loop = bb->loop_father; |
| if (curr_loop == current_loops->tree_root) |
| continue; |
| |
| for (loop = curr_loop; |
| loop != current_loops->tree_root; |
| loop = loop_outer (loop)) |
| bitmap_ior_into (&LOOP_DATA (loop)->regs_live, DF_LR_IN (bb)); |
| |
| bitmap_copy (&curr_regs_live, DF_LR_IN (bb)); |
| for (i = 0; i < ira_pressure_classes_num; i++) |
| curr_reg_pressure[ira_pressure_classes[i]] = 0; |
| EXECUTE_IF_SET_IN_BITMAP (&curr_regs_live, 0, j, bi) |
| change_pressure (j, true); |
| |
| FOR_BB_INSNS (bb, insn) |
| { |
| if (! NONDEBUG_INSN_P (insn)) |
| continue; |
| |
| mark_ref_regs (PATTERN (insn)); |
| n_regs_set = 0; |
| note_stores (PATTERN (insn), mark_reg_clobber, NULL); |
| |
| /* Mark any registers dead after INSN as dead now. */ |
| |
| for (link = REG_NOTES (insn); link; link = XEXP (link, 1)) |
| if (REG_NOTE_KIND (link) == REG_DEAD) |
| mark_reg_death (XEXP (link, 0)); |
| |
| /* Mark any registers set in INSN as live, |
| and mark them as conflicting with all other live regs. |
| Clobbers are processed again, so they conflict with |
| the registers that are set. */ |
| |
| note_stores (PATTERN (insn), mark_reg_store, NULL); |
| |
| #ifdef AUTO_INC_DEC |
| for (link = REG_NOTES (insn); link; link = XEXP (link, 1)) |
| if (REG_NOTE_KIND (link) == REG_INC) |
| mark_reg_store (XEXP (link, 0), NULL_RTX, NULL); |
| #endif |
| while (n_regs_set-- > 0) |
| { |
| rtx note = find_regno_note (insn, REG_UNUSED, |
| REGNO (regs_set[n_regs_set])); |
| if (! note) |
| continue; |
| |
| mark_reg_death (XEXP (note, 0)); |
| } |
| } |
| } |
| bitmap_clear (&curr_regs_live); |
| if (flag_ira_region == IRA_REGION_MIXED |
| || flag_ira_region == IRA_REGION_ALL) |
| FOR_EACH_LOOP (loop, 0) |
| { |
| EXECUTE_IF_SET_IN_BITMAP (&LOOP_DATA (loop)->regs_live, 0, j, bi) |
| if (! bitmap_bit_p (&LOOP_DATA (loop)->regs_ref, j)) |
| { |
| enum reg_class pressure_class; |
| int nregs; |
| |
| pressure_class = get_regno_pressure_class (j, &nregs); |
| LOOP_DATA (loop)->max_reg_pressure[pressure_class] -= nregs; |
| } |
| } |
| if (dump_file == NULL) |
| return; |
| FOR_EACH_LOOP (loop, 0) |
| { |
| parent = loop_outer (loop); |
| fprintf (dump_file, "\n Loop %d (parent %d, header bb%d, depth %d)\n", |
| loop->num, (parent == NULL ? -1 : parent->num), |
| loop->header->index, loop_depth (loop)); |
| fprintf (dump_file, "\n ref. regnos:"); |
| EXECUTE_IF_SET_IN_BITMAP (&LOOP_DATA (loop)->regs_ref, 0, j, bi) |
| fprintf (dump_file, " %d", j); |
| fprintf (dump_file, "\n live regnos:"); |
| EXECUTE_IF_SET_IN_BITMAP (&LOOP_DATA (loop)->regs_live, 0, j, bi) |
| fprintf (dump_file, " %d", j); |
| fprintf (dump_file, "\n Pressure:"); |
| for (i = 0; (int) i < ira_pressure_classes_num; i++) |
| { |
| enum reg_class pressure_class; |
| |
| pressure_class = ira_pressure_classes[i]; |
| if (LOOP_DATA (loop)->max_reg_pressure[pressure_class] == 0) |
| continue; |
| fprintf (dump_file, " %s=%d", reg_class_names[pressure_class], |
| LOOP_DATA (loop)->max_reg_pressure[pressure_class]); |
| } |
| fprintf (dump_file, "\n"); |
| } |
| } |
| |
| |
| |
| /* Move the invariants out of the loops. */ |
| |
| void |
| move_loop_invariants (void) |
| { |
| struct loop *loop; |
| |
| if (flag_ira_loop_pressure) |
| { |
| df_analyze (); |
| regstat_init_n_sets_and_refs (); |
| ira_set_pseudo_classes (true, dump_file); |
| calculate_loop_reg_pressure (); |
| regstat_free_n_sets_and_refs (); |
| } |
| df_set_flags (DF_EQ_NOTES + DF_DEFER_INSN_RESCAN); |
| /* Process the loops, innermost first. */ |
| FOR_EACH_LOOP (loop, LI_FROM_INNERMOST) |
| { |
| curr_loop = loop; |
| /* move_single_loop_invariants for very large loops |
| is time consuming and might need a lot of memory. */ |
| if (loop->num_nodes <= (unsigned) LOOP_INVARIANT_MAX_BBS_IN_LOOP) |
| move_single_loop_invariants (loop); |
| } |
| |
| FOR_EACH_LOOP (loop, 0) |
| { |
| free_loop_data (loop); |
| } |
| |
| if (flag_ira_loop_pressure) |
| /* There is no sense to keep this info because it was most |
| probably outdated by subsequent passes. */ |
| free_reg_info (); |
| free (invariant_table); |
| invariant_table = NULL; |
| invariant_table_size = 0; |
| |
| #ifdef ENABLE_CHECKING |
| verify_flow_info (); |
| #endif |
| } |