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[/] [openrisc/] [trunk/] [gnu-src/] [gcc-4.5.1/] [gcc/] [regrename.c] - Rev 325
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/* Register renaming for the GNU compiler. Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010 Free Software Foundation, Inc. This file is part of GCC. GCC is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3, or (at your option) any later version. GCC is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with GCC; see the file COPYING3. If not see <http://www.gnu.org/licenses/>. */ #include "config.h" #include "system.h" #include "coretypes.h" #include "tm.h" #include "rtl.h" #include "tm_p.h" #include "insn-config.h" #include "regs.h" #include "addresses.h" #include "hard-reg-set.h" #include "basic-block.h" #include "reload.h" #include "output.h" #include "function.h" #include "recog.h" #include "flags.h" #include "toplev.h" #include "obstack.h" #include "timevar.h" #include "tree-pass.h" #include "df.h" #if HOST_BITS_PER_WIDE_INT <= MAX_RECOG_OPERANDS #error "Use a different bitmap implementation for untracked_operands." #endif /* We keep linked lists of DU_HEAD structures, each of which describes a chain of occurrences of a reg. */ struct du_head { /* The next chain. */ struct du_head *next_chain; /* The first and last elements of this chain. */ struct du_chain *first, *last; /* Describes the register being tracked. */ unsigned regno, nregs; /* A unique id to be used as an index into the conflicts bitmaps. */ unsigned id; /* A bitmap to record conflicts with other chains. */ bitmap_head conflicts; /* Conflicts with untracked hard registers. */ HARD_REG_SET hard_conflicts; /* Nonzero if the chain is finished; zero if it is still open. */ unsigned int terminated:1; /* Nonzero if the chain crosses a call. */ unsigned int need_caller_save_reg:1; /* Nonzero if the register is used in a way that prevents renaming, such as the SET_DEST of a CALL_INSN or an asm operand that used to be a hard register. */ unsigned int cannot_rename:1; }; /* This struct describes a single occurrence of a register. */ struct du_chain { /* Links to the next occurrence of the register. */ struct du_chain *next_use; /* The insn where the register appears. */ rtx insn; /* The location inside the insn. */ rtx *loc; /* The register class required by the insn at this location. */ ENUM_BITFIELD(reg_class) cl : 16; }; enum scan_actions { terminate_write, terminate_dead, mark_all_read, mark_read, mark_write, /* mark_access is for marking the destination regs in REG_FRAME_RELATED_EXPR notes (as if they were read) so that the note is updated properly. */ mark_access }; static const char * const scan_actions_name[] = { "terminate_write", "terminate_dead", "mark_all_read", "mark_read", "mark_write", "mark_access" }; static struct obstack rename_obstack; static void do_replace (struct du_head *, int); static void scan_rtx_reg (rtx, rtx *, enum reg_class, enum scan_actions, enum op_type); static void scan_rtx_address (rtx, rtx *, enum reg_class, enum scan_actions, enum machine_mode); static void scan_rtx (rtx, rtx *, enum reg_class, enum scan_actions, enum op_type); static struct du_head *build_def_use (basic_block); static void dump_def_use_chain (struct du_head *); typedef struct du_head *du_head_p; DEF_VEC_P (du_head_p); DEF_VEC_ALLOC_P (du_head_p, heap); static VEC(du_head_p, heap) *id_to_chain; static void free_chain_data (void) { int i; du_head_p ptr; for (i = 0; VEC_iterate(du_head_p, id_to_chain, i, ptr); i++) bitmap_clear (&ptr->conflicts); VEC_free (du_head_p, heap, id_to_chain); } /* For a def-use chain HEAD, find which registers overlap its lifetime and set the corresponding bits in *PSET. */ static void merge_overlapping_regs (HARD_REG_SET *pset, struct du_head *head) { bitmap_iterator bi; unsigned i; IOR_HARD_REG_SET (*pset, head->hard_conflicts); EXECUTE_IF_SET_IN_BITMAP (&head->conflicts, 0, i, bi) { du_head_p other = VEC_index (du_head_p, id_to_chain, i); unsigned j = other->nregs; while (j-- > 0) SET_HARD_REG_BIT (*pset, other->regno + j); } } /* Perform register renaming on the current function. */ static unsigned int regrename_optimize (void) { int tick[FIRST_PSEUDO_REGISTER]; int this_tick = 0; basic_block bb; char *first_obj; df_set_flags (DF_LR_RUN_DCE); df_note_add_problem (); df_analyze (); df_set_flags (DF_DEFER_INSN_RESCAN); memset (tick, 0, sizeof tick); gcc_obstack_init (&rename_obstack); first_obj = XOBNEWVAR (&rename_obstack, char, 0); FOR_EACH_BB (bb) { struct du_head *all_chains = 0; HARD_REG_SET unavailable; #if 0 HARD_REG_SET regs_seen; CLEAR_HARD_REG_SET (regs_seen); #endif id_to_chain = VEC_alloc (du_head_p, heap, 0); CLEAR_HARD_REG_SET (unavailable); if (dump_file) fprintf (dump_file, "\nBasic block %d:\n", bb->index); all_chains = build_def_use (bb); if (dump_file) dump_def_use_chain (all_chains); CLEAR_HARD_REG_SET (unavailable); /* Don't clobber traceback for noreturn functions. */ if (frame_pointer_needed) { add_to_hard_reg_set (&unavailable, Pmode, FRAME_POINTER_REGNUM); #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM add_to_hard_reg_set (&unavailable, Pmode, HARD_FRAME_POINTER_REGNUM); #endif } while (all_chains) { int new_reg, best_new_reg, best_nregs; int n_uses; struct du_head *this_head = all_chains; struct du_chain *tmp; HARD_REG_SET this_unavailable; int reg = this_head->regno; int i; all_chains = this_head->next_chain; if (this_head->cannot_rename) continue; best_new_reg = reg; best_nregs = this_head->nregs; #if 0 /* This just disables optimization opportunities. */ /* Only rename once we've seen the reg more than once. */ if (! TEST_HARD_REG_BIT (regs_seen, reg)) { SET_HARD_REG_BIT (regs_seen, reg); continue; } #endif if (fixed_regs[reg] || global_regs[reg] #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM || (frame_pointer_needed && reg == HARD_FRAME_POINTER_REGNUM) #else || (frame_pointer_needed && reg == FRAME_POINTER_REGNUM) #endif ) continue; COPY_HARD_REG_SET (this_unavailable, unavailable); /* Count number of uses, and narrow the set of registers we can use for renaming. */ n_uses = 0; for (tmp = this_head->first; tmp; tmp = tmp->next_use) { if (DEBUG_INSN_P (tmp->insn)) continue; n_uses++; IOR_COMPL_HARD_REG_SET (this_unavailable, reg_class_contents[tmp->cl]); } if (n_uses < 2) continue; if (this_head->need_caller_save_reg) IOR_HARD_REG_SET (this_unavailable, call_used_reg_set); merge_overlapping_regs (&this_unavailable, this_head); /* Now potential_regs is a reasonable approximation, let's have a closer look at each register still in there. */ for (new_reg = 0; new_reg < FIRST_PSEUDO_REGISTER; new_reg++) { enum machine_mode mode = GET_MODE (*this_head->first->loc); int nregs = hard_regno_nregs[new_reg][mode]; for (i = nregs - 1; i >= 0; --i) if (TEST_HARD_REG_BIT (this_unavailable, new_reg + i) || fixed_regs[new_reg + i] || global_regs[new_reg + i] /* Can't use regs which aren't saved by the prologue. */ || (! df_regs_ever_live_p (new_reg + i) && ! call_used_regs[new_reg + i]) #ifdef LEAF_REGISTERS /* We can't use a non-leaf register if we're in a leaf function. */ || (current_function_is_leaf && !LEAF_REGISTERS[new_reg + i]) #endif #ifdef HARD_REGNO_RENAME_OK || ! HARD_REGNO_RENAME_OK (reg + i, new_reg + i) #endif ) break; if (i >= 0) continue; /* See whether it accepts all modes that occur in definition and uses. */ for (tmp = this_head->first; tmp; tmp = tmp->next_use) if ((! HARD_REGNO_MODE_OK (new_reg, GET_MODE (*tmp->loc)) && ! DEBUG_INSN_P (tmp->insn)) || (this_head->need_caller_save_reg && ! (HARD_REGNO_CALL_PART_CLOBBERED (reg, GET_MODE (*tmp->loc))) && (HARD_REGNO_CALL_PART_CLOBBERED (new_reg, GET_MODE (*tmp->loc))))) break; if (! tmp) { if (tick[best_new_reg] > tick[new_reg]) { best_new_reg = new_reg; best_nregs = nregs; } } } if (dump_file) { fprintf (dump_file, "Register %s in insn %d", reg_names[reg], INSN_UID (this_head->first->insn)); if (this_head->need_caller_save_reg) fprintf (dump_file, " crosses a call"); } if (best_new_reg == reg) { tick[reg] = ++this_tick; if (dump_file) fprintf (dump_file, "; no available better choice\n"); continue; } if (dump_file) fprintf (dump_file, ", renamed as %s\n", reg_names[best_new_reg]); do_replace (this_head, best_new_reg); this_head->regno = best_new_reg; this_head->nregs = best_nregs; tick[best_new_reg] = ++this_tick; df_set_regs_ever_live (best_new_reg, true); } free_chain_data (); obstack_free (&rename_obstack, first_obj); } obstack_free (&rename_obstack, NULL); if (dump_file) fputc ('\n', dump_file); return 0; } static void do_replace (struct du_head *head, int reg) { struct du_chain *chain; unsigned int base_regno = head->regno; bool found_note = false; gcc_assert (! DEBUG_INSN_P (head->first->insn)); for (chain = head->first; chain; chain = chain->next_use) { unsigned int regno = ORIGINAL_REGNO (*chain->loc); struct reg_attrs *attr = REG_ATTRS (*chain->loc); int reg_ptr = REG_POINTER (*chain->loc); if (DEBUG_INSN_P (chain->insn) && REGNO (*chain->loc) != base_regno) INSN_VAR_LOCATION_LOC (chain->insn) = gen_rtx_UNKNOWN_VAR_LOC (); else { rtx note; *chain->loc = gen_raw_REG (GET_MODE (*chain->loc), reg); if (regno >= FIRST_PSEUDO_REGISTER) ORIGINAL_REGNO (*chain->loc) = regno; REG_ATTRS (*chain->loc) = attr; REG_POINTER (*chain->loc) = reg_ptr; for (note = REG_NOTES (chain->insn); note; note = XEXP (note, 1)) { enum reg_note kind = REG_NOTE_KIND (note); if (kind == REG_DEAD || kind == REG_UNUSED) { rtx reg = XEXP (note, 0); gcc_assert (HARD_REGISTER_P (reg)); if (REGNO (reg) == base_regno) { found_note = true; if (kind == REG_DEAD && reg_set_p (*chain->loc, chain->insn)) remove_note (chain->insn, note); else XEXP (note, 0) = *chain->loc; break; } } } } df_insn_rescan (chain->insn); } if (!found_note) { /* If the chain's first insn is the same as the last, we should have found a REG_UNUSED note. */ gcc_assert (head->first->insn != head->last->insn); if (!reg_set_p (*head->last->loc, head->last->insn)) add_reg_note (head->last->insn, REG_DEAD, *head->last->loc); } } /* Walk all chains starting with CHAINS and record that they conflict with another chain whose id is ID. */ static void mark_conflict (struct du_head *chains, unsigned id) { while (chains) { bitmap_set_bit (&chains->conflicts, id); chains = chains->next_chain; } } /* True if we found a register with a size mismatch, which means that we can't track its lifetime accurately. If so, we abort the current block without renaming. */ static bool fail_current_block; /* The id to be given to the next opened chain. */ static unsigned current_id; /* List of currently open chains, and closed chains that can be renamed. */ static struct du_head *open_chains; static struct du_head *closed_chains; /* Bitmap of open chains. The bits set always match the list found in open_chains. */ static bitmap_head open_chains_set; /* Record the registers being tracked in open_chains. */ static HARD_REG_SET live_in_chains; /* Record the registers that are live but not tracked. The intersection between this and live_in_chains is empty. */ static HARD_REG_SET live_hard_regs; /* Return true if OP is a reg for which all bits are set in PSET, false if all bits are clear. In other cases, set fail_current_block and return false. */ static bool verify_reg_in_set (rtx op, HARD_REG_SET *pset) { unsigned regno, nregs; bool all_live, all_dead; if (!REG_P (op)) return false; regno = REGNO (op); nregs = hard_regno_nregs[regno][GET_MODE (op)]; all_live = all_dead = true; while (nregs-- > 0) if (TEST_HARD_REG_BIT (*pset, regno + nregs)) all_dead = false; else all_live = false; if (!all_dead && !all_live) { fail_current_block = true; return false; } return all_live; } /* Return true if OP is a reg that is being tracked already in some form. May set fail_current_block if it sees an unhandled case of overlap. */ static bool verify_reg_tracked (rtx op) { return (verify_reg_in_set (op, &live_hard_regs) || verify_reg_in_set (op, &live_in_chains)); } /* Called through note_stores. DATA points to a rtx_code, either SET or CLOBBER, which tells us which kind of rtx to look at. If we have a match, record the set register in live_hard_regs and in the hard_conflicts bitmap of open chains. */ static void note_sets_clobbers (rtx x, const_rtx set, void *data) { enum rtx_code code = *(enum rtx_code *)data; struct du_head *chain; if (GET_CODE (x) == SUBREG) x = SUBREG_REG (x); if (!REG_P (x) || GET_CODE (set) != code) return; /* There must not be pseudos at this point. */ gcc_assert (HARD_REGISTER_P (x)); add_to_hard_reg_set (&live_hard_regs, GET_MODE (x), REGNO (x)); for (chain = open_chains; chain; chain = chain->next_chain) add_to_hard_reg_set (&chain->hard_conflicts, GET_MODE (x), REGNO (x)); } /* Create a new chain for THIS_NREGS registers starting at THIS_REGNO, and record its occurrence in *LOC, which is being written to in INSN. This access requires a register of class CL. */ static void create_new_chain (unsigned this_regno, unsigned this_nregs, rtx *loc, rtx insn, enum reg_class cl) { struct du_head *head = XOBNEW (&rename_obstack, struct du_head); struct du_chain *this_du; int nregs; head->next_chain = open_chains; open_chains = head; head->regno = this_regno; head->nregs = this_nregs; head->need_caller_save_reg = 0; head->cannot_rename = 0; head->terminated = 0; VEC_safe_push (du_head_p, heap, id_to_chain, head); head->id = current_id++; bitmap_initialize (&head->conflicts, &bitmap_default_obstack); bitmap_copy (&head->conflicts, &open_chains_set); mark_conflict (open_chains, head->id); /* Since we're tracking this as a chain now, remove it from the list of conflicting live hard registers and track it in live_in_chains instead. */ nregs = head->nregs; while (nregs-- > 0) { SET_HARD_REG_BIT (live_in_chains, head->regno + nregs); CLEAR_HARD_REG_BIT (live_hard_regs, head->regno + nregs); } COPY_HARD_REG_SET (head->hard_conflicts, live_hard_regs); bitmap_set_bit (&open_chains_set, head->id); open_chains = head; if (dump_file) { fprintf (dump_file, "Creating chain %s (%d)", reg_names[head->regno], head->id); if (insn != NULL_RTX) fprintf (dump_file, " at insn %d", INSN_UID (insn)); fprintf (dump_file, "\n"); } if (insn == NULL_RTX) { head->first = head->last = NULL; return; } this_du = XOBNEW (&rename_obstack, struct du_chain); head->first = head->last = this_du; this_du->next_use = 0; this_du->loc = loc; this_du->insn = insn; this_du->cl = cl; } static void scan_rtx_reg (rtx insn, rtx *loc, enum reg_class cl, enum scan_actions action, enum op_type type) { struct du_head **p; rtx x = *loc; enum machine_mode mode = GET_MODE (x); unsigned this_regno = REGNO (x); unsigned this_nregs = hard_regno_nregs[this_regno][mode]; if (action == mark_write) { if (type == OP_OUT) create_new_chain (this_regno, this_nregs, loc, insn, cl); return; } if ((type == OP_OUT) != (action == terminate_write || action == mark_access)) return; for (p = &open_chains; *p;) { struct du_head *head = *p; struct du_head *next = head->next_chain; int exact_match = (head->regno == this_regno && head->nregs == this_nregs); int superset = (this_regno <= head->regno && this_regno + this_nregs >= head->regno + head->nregs); int subset = (this_regno >= head->regno && this_regno + this_nregs <= head->regno + head->nregs); if (head->terminated || head->regno + head->nregs <= this_regno || this_regno + this_nregs <= head->regno) { p = &head->next_chain; continue; } if (action == mark_read || action == mark_access) { /* ??? Class NO_REGS can happen if the md file makes use of EXTRA_CONSTRAINTS to match registers. Which is arguably wrong, but there we are. */ if (cl == NO_REGS || (!exact_match && !DEBUG_INSN_P (insn))) { if (dump_file) fprintf (dump_file, "Cannot rename chain %s (%d) at insn %d (%s)\n", reg_names[head->regno], head->id, INSN_UID (insn), scan_actions_name[(int) action]); head->cannot_rename = 1; if (superset) { unsigned nregs = this_nregs; head->regno = this_regno; head->nregs = this_nregs; while (nregs-- > 0) SET_HARD_REG_BIT (live_in_chains, head->regno + nregs); if (dump_file) fprintf (dump_file, "Widening register in chain %s (%d) at insn %d\n", reg_names[head->regno], head->id, INSN_UID (insn)); } else if (!subset) { fail_current_block = true; if (dump_file) fprintf (dump_file, "Failing basic block due to unhandled overlap\n"); } } else { struct du_chain *this_du; this_du = XOBNEW (&rename_obstack, struct du_chain); this_du->next_use = 0; this_du->loc = loc; this_du->insn = insn; this_du->cl = cl; if (head->first == NULL) head->first = this_du; else head->last->next_use = this_du; head->last = this_du; } /* Avoid adding the same location in a DEBUG_INSN multiple times, which could happen with non-exact overlap. */ if (DEBUG_INSN_P (insn)) return; /* Otherwise, find any other chains that do not match exactly; ensure they all get marked unrenamable. */ p = &head->next_chain; continue; } /* Whether the terminated chain can be used for renaming depends on the action and this being an exact match. In either case, we remove this element from open_chains. */ if ((action == terminate_dead || action == terminate_write) && superset) { unsigned nregs; head->terminated = 1; head->next_chain = closed_chains; closed_chains = head; bitmap_clear_bit (&open_chains_set, head->id); nregs = head->nregs; while (nregs-- > 0) CLEAR_HARD_REG_BIT (live_in_chains, head->regno + nregs); *p = next; if (dump_file) fprintf (dump_file, "Closing chain %s (%d) at insn %d (%s)\n", reg_names[head->regno], head->id, INSN_UID (insn), scan_actions_name[(int) action]); } else if (action == terminate_dead || action == terminate_write) { /* In this case, tracking liveness gets too hard. Fail the entire basic block. */ if (dump_file) fprintf (dump_file, "Failing basic block due to unhandled overlap\n"); fail_current_block = true; return; } else { head->cannot_rename = 1; if (dump_file) fprintf (dump_file, "Cannot rename chain %s (%d) at insn %d (%s)\n", reg_names[head->regno], head->id, INSN_UID (insn), scan_actions_name[(int) action]); p = &head->next_chain; } } } /* Adapted from find_reloads_address_1. CL is INDEX_REG_CLASS or BASE_REG_CLASS depending on how the register is being considered. */ static void scan_rtx_address (rtx insn, rtx *loc, enum reg_class cl, enum scan_actions action, enum machine_mode mode) { rtx x = *loc; RTX_CODE code = GET_CODE (x); const char *fmt; int i, j; if (action == mark_write || action == mark_access) return; switch (code) { case PLUS: { rtx orig_op0 = XEXP (x, 0); rtx orig_op1 = XEXP (x, 1); RTX_CODE code0 = GET_CODE (orig_op0); RTX_CODE code1 = GET_CODE (orig_op1); rtx op0 = orig_op0; rtx op1 = orig_op1; rtx *locI = NULL; rtx *locB = NULL; enum rtx_code index_code = SCRATCH; if (GET_CODE (op0) == SUBREG) { op0 = SUBREG_REG (op0); code0 = GET_CODE (op0); } if (GET_CODE (op1) == SUBREG) { op1 = SUBREG_REG (op1); code1 = GET_CODE (op1); } if (code0 == MULT || code0 == SIGN_EXTEND || code0 == TRUNCATE || code0 == ZERO_EXTEND || code1 == MEM) { locI = &XEXP (x, 0); locB = &XEXP (x, 1); index_code = GET_CODE (*locI); } else if (code1 == MULT || code1 == SIGN_EXTEND || code1 == TRUNCATE || code1 == ZERO_EXTEND || code0 == MEM) { locI = &XEXP (x, 1); locB = &XEXP (x, 0); index_code = GET_CODE (*locI); } else if (code0 == CONST_INT || code0 == CONST || code0 == SYMBOL_REF || code0 == LABEL_REF) { locB = &XEXP (x, 1); index_code = GET_CODE (XEXP (x, 0)); } else if (code1 == CONST_INT || code1 == CONST || code1 == SYMBOL_REF || code1 == LABEL_REF) { locB = &XEXP (x, 0); index_code = GET_CODE (XEXP (x, 1)); } else if (code0 == REG && code1 == REG) { int index_op; unsigned regno0 = REGNO (op0), regno1 = REGNO (op1); if (REGNO_OK_FOR_INDEX_P (regno1) && regno_ok_for_base_p (regno0, mode, PLUS, REG)) index_op = 1; else if (REGNO_OK_FOR_INDEX_P (regno0) && regno_ok_for_base_p (regno1, mode, PLUS, REG)) index_op = 0; else if (regno_ok_for_base_p (regno0, mode, PLUS, REG) || REGNO_OK_FOR_INDEX_P (regno1)) index_op = 1; else if (regno_ok_for_base_p (regno1, mode, PLUS, REG)) index_op = 0; else index_op = 1; locI = &XEXP (x, index_op); locB = &XEXP (x, !index_op); index_code = GET_CODE (*locI); } else if (code0 == REG) { locI = &XEXP (x, 0); locB = &XEXP (x, 1); index_code = GET_CODE (*locI); } else if (code1 == REG) { locI = &XEXP (x, 1); locB = &XEXP (x, 0); index_code = GET_CODE (*locI); } if (locI) scan_rtx_address (insn, locI, INDEX_REG_CLASS, action, mode); if (locB) scan_rtx_address (insn, locB, base_reg_class (mode, PLUS, index_code), action, mode); return; } case POST_INC: case POST_DEC: case POST_MODIFY: case PRE_INC: case PRE_DEC: case PRE_MODIFY: #ifndef AUTO_INC_DEC /* If the target doesn't claim to handle autoinc, this must be something special, like a stack push. Kill this chain. */ action = mark_all_read; #endif break; case MEM: scan_rtx_address (insn, &XEXP (x, 0), base_reg_class (GET_MODE (x), MEM, SCRATCH), action, GET_MODE (x)); return; case REG: scan_rtx_reg (insn, loc, cl, action, OP_IN); return; default: break; } fmt = GET_RTX_FORMAT (code); for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--) { if (fmt[i] == 'e') scan_rtx_address (insn, &XEXP (x, i), cl, action, mode); else if (fmt[i] == 'E') for (j = XVECLEN (x, i) - 1; j >= 0; j--) scan_rtx_address (insn, &XVECEXP (x, i, j), cl, action, mode); } } static void scan_rtx (rtx insn, rtx *loc, enum reg_class cl, enum scan_actions action, enum op_type type) { const char *fmt; rtx x = *loc; enum rtx_code code = GET_CODE (x); int i, j; code = GET_CODE (x); switch (code) { case CONST: case CONST_INT: case CONST_DOUBLE: case CONST_FIXED: case CONST_VECTOR: case SYMBOL_REF: case LABEL_REF: case CC0: case PC: return; case REG: scan_rtx_reg (insn, loc, cl, action, type); return; case MEM: scan_rtx_address (insn, &XEXP (x, 0), base_reg_class (GET_MODE (x), MEM, SCRATCH), action, GET_MODE (x)); return; case SET: scan_rtx (insn, &SET_SRC (x), cl, action, OP_IN); scan_rtx (insn, &SET_DEST (x), cl, action, (GET_CODE (PATTERN (insn)) == COND_EXEC && verify_reg_tracked (SET_DEST (x))) ? OP_INOUT : OP_OUT); return; case STRICT_LOW_PART: scan_rtx (insn, &XEXP (x, 0), cl, action, verify_reg_tracked (XEXP (x, 0)) ? OP_INOUT : OP_OUT); return; case ZERO_EXTRACT: case SIGN_EXTRACT: scan_rtx (insn, &XEXP (x, 0), cl, action, (type == OP_IN ? OP_IN : verify_reg_tracked (XEXP (x, 0)) ? OP_INOUT : OP_OUT)); scan_rtx (insn, &XEXP (x, 1), cl, action, OP_IN); scan_rtx (insn, &XEXP (x, 2), cl, action, OP_IN); return; case POST_INC: case PRE_INC: case POST_DEC: case PRE_DEC: case POST_MODIFY: case PRE_MODIFY: /* Should only happen inside MEM. */ gcc_unreachable (); case CLOBBER: scan_rtx (insn, &SET_DEST (x), cl, action, (GET_CODE (PATTERN (insn)) == COND_EXEC && verify_reg_tracked (SET_DEST (x))) ? OP_INOUT : OP_OUT); return; case EXPR_LIST: scan_rtx (insn, &XEXP (x, 0), cl, action, type); if (XEXP (x, 1)) scan_rtx (insn, &XEXP (x, 1), cl, action, type); return; default: break; } fmt = GET_RTX_FORMAT (code); for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--) { if (fmt[i] == 'e') scan_rtx (insn, &XEXP (x, i), cl, action, type); else if (fmt[i] == 'E') for (j = XVECLEN (x, i) - 1; j >= 0; j--) scan_rtx (insn, &XVECEXP (x, i, j), cl, action, type); } } /* Hide operands of the current insn (of which there are N_OPS) by substituting cc0 for them. Previous values are stored in the OLD_OPERANDS and OLD_DUPS. For every bit set in DO_NOT_HIDE, we leave the operand alone. If INOUT_AND_EC_ONLY is set, we only do this for OP_INOUT type operands and earlyclobbers. */ static void hide_operands (int n_ops, rtx *old_operands, rtx *old_dups, unsigned HOST_WIDE_INT do_not_hide, bool inout_and_ec_only) { int i; int alt = which_alternative; for (i = 0; i < n_ops; i++) { old_operands[i] = recog_data.operand[i]; /* Don't squash match_operator or match_parallel here, since we don't know that all of the contained registers are reachable by proper operands. */ if (recog_data.constraints[i][0] == '\0') continue; if (do_not_hide & (1 << i)) continue; if (!inout_and_ec_only || recog_data.operand_type[i] == OP_INOUT || recog_op_alt[i][alt].earlyclobber) *recog_data.operand_loc[i] = cc0_rtx; } for (i = 0; i < recog_data.n_dups; i++) { int opn = recog_data.dup_num[i]; old_dups[i] = *recog_data.dup_loc[i]; if (do_not_hide & (1 << opn)) continue; if (!inout_and_ec_only || recog_data.operand_type[opn] == OP_INOUT || recog_op_alt[opn][alt].earlyclobber) *recog_data.dup_loc[i] = cc0_rtx; } } /* Undo the substitution performed by hide_operands. INSN is the insn we are processing; the arguments are the same as in hide_operands. */ static void restore_operands (rtx insn, int n_ops, rtx *old_operands, rtx *old_dups) { int i; for (i = 0; i < recog_data.n_dups; i++) *recog_data.dup_loc[i] = old_dups[i]; for (i = 0; i < n_ops; i++) *recog_data.operand_loc[i] = old_operands[i]; if (recog_data.n_dups) df_insn_rescan (insn); } /* For each output operand of INSN, call scan_rtx to create a new open chain. Do this only for normal or earlyclobber outputs, depending on EARLYCLOBBER. */ static void record_out_operands (rtx insn, bool earlyclobber) { int n_ops = recog_data.n_operands; int alt = which_alternative; int i; for (i = 0; i < n_ops + recog_data.n_dups; i++) { int opn = i < n_ops ? i : recog_data.dup_num[i - n_ops]; rtx *loc = (i < n_ops ? recog_data.operand_loc[opn] : recog_data.dup_loc[i - n_ops]); rtx op = *loc; enum reg_class cl = recog_op_alt[opn][alt].cl; struct du_head *prev_open; if (recog_data.operand_type[opn] != OP_OUT || recog_op_alt[opn][alt].earlyclobber != earlyclobber) continue; prev_open = open_chains; scan_rtx (insn, loc, cl, mark_write, OP_OUT); /* ??? Many targets have output constraints on the SET_DEST of a call insn, which is stupid, since these are certainly ABI defined hard registers. For these, and for asm operands that originally referenced hard registers, we must record that the chain cannot be renamed. */ if (CALL_P (insn) || (asm_noperands (PATTERN (insn)) > 0 && REG_P (op) && REGNO (op) == ORIGINAL_REGNO (op))) { if (prev_open != open_chains) open_chains->cannot_rename = 1; } } } /* Build def/use chain. */ static struct du_head * build_def_use (basic_block bb) { rtx insn; df_ref *def_rec; unsigned HOST_WIDE_INT untracked_operands; open_chains = closed_chains = NULL; fail_current_block = false; current_id = 0; bitmap_initialize (&open_chains_set, &bitmap_default_obstack); CLEAR_HARD_REG_SET (live_in_chains); REG_SET_TO_HARD_REG_SET (live_hard_regs, df_get_live_in (bb)); for (def_rec = df_get_artificial_defs (bb->index); *def_rec; def_rec++) { df_ref def = *def_rec; if (DF_REF_FLAGS (def) & DF_REF_AT_TOP) SET_HARD_REG_BIT (live_hard_regs, DF_REF_REGNO (def)); } for (insn = BB_HEAD (bb); ; insn = NEXT_INSN (insn)) { if (NONDEBUG_INSN_P (insn)) { int n_ops; rtx note; rtx old_operands[MAX_RECOG_OPERANDS]; rtx old_dups[MAX_DUP_OPERANDS]; int i; int alt; int predicated; enum rtx_code set_code = SET; enum rtx_code clobber_code = CLOBBER; /* Process the insn, determining its effect on the def-use chains and live hard registers. We perform the following steps with the register references in the insn, simulating its effect: (1) Deal with earlyclobber operands and CLOBBERs of non-operands by creating chains and marking hard regs live. (2) Any read outside an operand causes any chain it overlaps with to be marked unrenamable. (3) Any read inside an operand is added if there's already an open chain for it. (4) For any REG_DEAD note we find, close open chains that overlap it. (5) For any non-earlyclobber write we find, close open chains that overlap it. (6) For any non-earlyclobber write we find in an operand, make a new chain or mark the hard register as live. (7) For any REG_UNUSED, close any chains we just opened. We cannot deal with situations where we track a reg in one mode and see a reference in another mode; these will cause the chain to be marked unrenamable or even cause us to abort the entire basic block. */ extract_insn (insn); if (! constrain_operands (1)) fatal_insn_not_found (insn); preprocess_constraints (); alt = which_alternative; n_ops = recog_data.n_operands; untracked_operands = 0; /* Simplify the code below by rewriting things to reflect matching constraints. Also promote OP_OUT to OP_INOUT in predicated instructions, but only for register operands that are already tracked, so that we can create a chain when the first SET makes a register live. */ predicated = GET_CODE (PATTERN (insn)) == COND_EXEC; for (i = 0; i < n_ops; ++i) { rtx op = recog_data.operand[i]; int matches = recog_op_alt[i][alt].matches; if (matches >= 0) recog_op_alt[i][alt].cl = recog_op_alt[matches][alt].cl; if (matches >= 0 || recog_op_alt[i][alt].matched >= 0 || (predicated && recog_data.operand_type[i] == OP_OUT)) { recog_data.operand_type[i] = OP_INOUT; /* A special case to deal with instruction patterns that have matching operands with different modes. If we're not already tracking such a reg, we won't start here, and we must instead make sure to make the operand visible to the machinery that tracks hard registers. */ if (matches >= 0 && (GET_MODE_SIZE (recog_data.operand_mode[i]) != GET_MODE_SIZE (recog_data.operand_mode[matches])) && !verify_reg_in_set (op, &live_in_chains)) { untracked_operands |= 1 << i; untracked_operands |= 1 << matches; } } /* If there's an in-out operand with a register that is not being tracked at all yet, open a chain. */ if (recog_data.operand_type[i] == OP_INOUT && !(untracked_operands & (1 << i)) && REG_P (op) && !verify_reg_tracked (op)) { enum machine_mode mode = GET_MODE (op); unsigned this_regno = REGNO (op); unsigned this_nregs = hard_regno_nregs[this_regno][mode]; create_new_chain (this_regno, this_nregs, NULL, NULL_RTX, NO_REGS); } } if (fail_current_block) break; /* Step 1a: Mark hard registers that are clobbered in this insn, outside an operand, as live. */ hide_operands (n_ops, old_operands, old_dups, untracked_operands, false); note_stores (PATTERN (insn), note_sets_clobbers, &clobber_code); restore_operands (insn, n_ops, old_operands, old_dups); /* Step 1b: Begin new chains for earlyclobbered writes inside operands. */ record_out_operands (insn, true); /* Step 2: Mark chains for which we have reads outside operands as unrenamable. We do this by munging all operands into CC0, and closing everything remaining. */ hide_operands (n_ops, old_operands, old_dups, untracked_operands, false); scan_rtx (insn, &PATTERN (insn), NO_REGS, mark_all_read, OP_IN); restore_operands (insn, n_ops, old_operands, old_dups); /* Step 2B: Can't rename function call argument registers. */ if (CALL_P (insn) && CALL_INSN_FUNCTION_USAGE (insn)) scan_rtx (insn, &CALL_INSN_FUNCTION_USAGE (insn), NO_REGS, mark_all_read, OP_IN); /* Step 2C: Can't rename asm operands that were originally hard registers. */ if (asm_noperands (PATTERN (insn)) > 0) for (i = 0; i < n_ops; i++) { rtx *loc = recog_data.operand_loc[i]; rtx op = *loc; if (REG_P (op) && REGNO (op) == ORIGINAL_REGNO (op) && (recog_data.operand_type[i] == OP_IN || recog_data.operand_type[i] == OP_INOUT)) scan_rtx (insn, loc, NO_REGS, mark_all_read, OP_IN); } /* Step 3: Append to chains for reads inside operands. */ for (i = 0; i < n_ops + recog_data.n_dups; i++) { int opn = i < n_ops ? i : recog_data.dup_num[i - n_ops]; rtx *loc = (i < n_ops ? recog_data.operand_loc[opn] : recog_data.dup_loc[i - n_ops]); enum reg_class cl = recog_op_alt[opn][alt].cl; enum op_type type = recog_data.operand_type[opn]; /* Don't scan match_operand here, since we've no reg class information to pass down. Any operands that we could substitute in will be represented elsewhere. */ if (recog_data.constraints[opn][0] == '\0' || untracked_operands & (1 << opn)) continue; if (recog_op_alt[opn][alt].is_address) scan_rtx_address (insn, loc, cl, mark_read, VOIDmode); else scan_rtx (insn, loc, cl, mark_read, type); } /* Step 3B: Record updates for regs in REG_INC notes, and source regs in REG_FRAME_RELATED_EXPR notes. */ for (note = REG_NOTES (insn); note; note = XEXP (note, 1)) if (REG_NOTE_KIND (note) == REG_INC || REG_NOTE_KIND (note) == REG_FRAME_RELATED_EXPR) scan_rtx (insn, &XEXP (note, 0), ALL_REGS, mark_read, OP_INOUT); /* Step 4: Close chains for registers that die here. */ for (note = REG_NOTES (insn); note; note = XEXP (note, 1)) if (REG_NOTE_KIND (note) == REG_DEAD) { remove_from_hard_reg_set (&live_hard_regs, GET_MODE (XEXP (note, 0)), REGNO (XEXP (note, 0))); scan_rtx (insn, &XEXP (note, 0), NO_REGS, terminate_dead, OP_IN); } /* Step 4B: If this is a call, any chain live at this point requires a caller-saved reg. */ if (CALL_P (insn)) { struct du_head *p; for (p = open_chains; p; p = p->next_chain) p->need_caller_save_reg = 1; } /* Step 5: Close open chains that overlap writes. Similar to step 2, we hide in-out operands, since we do not want to close these chains. We also hide earlyclobber operands, since we've opened chains for them in step 1, and earlier chains they would overlap with must have been closed at the previous insn at the latest, as such operands cannot possibly overlap with any input operands. */ hide_operands (n_ops, old_operands, old_dups, untracked_operands, true); scan_rtx (insn, &PATTERN (insn), NO_REGS, terminate_write, OP_IN); restore_operands (insn, n_ops, old_operands, old_dups); /* Step 6a: Mark hard registers that are set in this insn, outside an operand, as live. */ hide_operands (n_ops, old_operands, old_dups, untracked_operands, false); note_stores (PATTERN (insn), note_sets_clobbers, &set_code); restore_operands (insn, n_ops, old_operands, old_dups); /* Step 6b: Begin new chains for writes inside operands. */ record_out_operands (insn, false); /* Step 6c: Record destination regs in REG_FRAME_RELATED_EXPR notes for update. */ for (note = REG_NOTES (insn); note; note = XEXP (note, 1)) if (REG_NOTE_KIND (note) == REG_FRAME_RELATED_EXPR) scan_rtx (insn, &XEXP (note, 0), ALL_REGS, mark_access, OP_INOUT); /* Step 7: Close chains for registers that were never really used here. */ for (note = REG_NOTES (insn); note; note = XEXP (note, 1)) if (REG_NOTE_KIND (note) == REG_UNUSED) { remove_from_hard_reg_set (&live_hard_regs, GET_MODE (XEXP (note, 0)), REGNO (XEXP (note, 0))); scan_rtx (insn, &XEXP (note, 0), NO_REGS, terminate_dead, OP_IN); } } else if (DEBUG_INSN_P (insn) && !VAR_LOC_UNKNOWN_P (INSN_VAR_LOCATION_LOC (insn))) { scan_rtx (insn, &INSN_VAR_LOCATION_LOC (insn), ALL_REGS, mark_read, OP_IN); } if (insn == BB_END (bb)) break; } bitmap_clear (&open_chains_set); if (fail_current_block) return NULL; /* Since we close every chain when we find a REG_DEAD note, anything that is still open lives past the basic block, so it can't be renamed. */ return closed_chains; } /* Dump all def/use chains in CHAINS to DUMP_FILE. They are printed in reverse order as that's how we build them. */ static void dump_def_use_chain (struct du_head *head) { while (head) { struct du_chain *this_du = head->first; fprintf (dump_file, "Register %s (%d):", reg_names[head->regno], head->nregs); while (this_du) { fprintf (dump_file, " %d [%s]", INSN_UID (this_du->insn), reg_class_names[this_du->cl]); this_du = this_du->next_use; } fprintf (dump_file, "\n"); head = head->next_chain; } } static bool gate_handle_regrename (void) { return (optimize > 0 && (flag_rename_registers)); } struct rtl_opt_pass pass_regrename = { { RTL_PASS, "rnreg", /* name */ gate_handle_regrename, /* gate */ regrename_optimize, /* execute */ NULL, /* sub */ NULL, /* next */ 0, /* static_pass_number */ TV_RENAME_REGISTERS, /* tv_id */ 0, /* properties_required */ 0, /* properties_provided */ 0, /* properties_destroyed */ 0, /* todo_flags_start */ TODO_df_finish | TODO_verify_rtl_sharing | TODO_dump_func /* todo_flags_finish */ } };
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