/* Instruction scheduling pass. This file computes dependencies between instructions. Copyright (C) 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004 Free Software Foundation, Inc. Contributed by Michael Tiemann (tiemann@cygnus.com) Enhanced by, and currently maintained by, Jim Wilson (wilson@cygnus.com) This file is part of GCC. GCC is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2, or (at your option) any later version. GCC is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with GCC; see the file COPYING. If not, write to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ #include "config.h" #include "system.h" #include "coretypes.h" #include "tm.h" #include "toplev.h" #include "rtl.h" #include "tm_p.h" #include "hard-reg-set.h" #include "basic-block.h" #include "regs.h" #include "function.h" #include "flags.h" #include "insn-config.h" #include "insn-attr.h" #include "except.h" #include "toplev.h" #include "recog.h" #include "sched-int.h" #include "params.h" #include "cselib.h" #include "df.h" static regset_head reg_pending_sets_head; static regset_head reg_pending_clobbers_head; static regset_head reg_pending_uses_head; static regset reg_pending_sets; static regset reg_pending_clobbers; static regset reg_pending_uses; /* The following enumeration values tell us what dependencies we should use to implement the barrier. We use true-dependencies for TRUE_BARRIER and anti-dependencies for MOVE_BARRIER. */ enum reg_pending_barrier_mode { NOT_A_BARRIER = 0, MOVE_BARRIER, TRUE_BARRIER }; static enum reg_pending_barrier_mode reg_pending_barrier; /* To speed up the test for duplicate dependency links we keep a record of dependencies created by add_dependence when the average number of instructions in a basic block is very large. Studies have shown that there is typically around 5 instructions between branches for typical C code. So we can make a guess that the average basic block is approximately 5 instructions long; we will choose 100X the average size as a very large basic block. Each insn has associated bitmaps for its dependencies. Each bitmap has enough entries to represent a dependency on any other insn in the insn chain. All bitmap for true dependencies cache is allocated then the rest two ones are also allocated. */ static bitmap_head *true_dependency_cache; static bitmap_head *anti_dependency_cache; static bitmap_head *output_dependency_cache; int cache_size; /* To speed up checking consistency of formed forward insn dependencies we use the following cache. Another possible solution could be switching off checking duplication of insns in forward dependencies. */ #ifdef ENABLE_CHECKING static bitmap_head *forward_dependency_cache; #endif static int deps_may_trap_p (rtx); static void add_dependence_list (rtx, rtx, enum reg_note); static void add_dependence_list_and_free (rtx, rtx *, enum reg_note); static void set_sched_group_p (rtx); static void flush_pending_lists (struct deps *, rtx, int, int); static void sched_analyze_1 (struct deps *, rtx, rtx); static void sched_analyze_2 (struct deps *, rtx, rtx); static void sched_analyze_insn (struct deps *, rtx, rtx, rtx); static rtx get_condition (rtx); static int conditions_mutex_p (rtx, rtx); /* Return nonzero if a load of the memory reference MEM can cause a trap. */ static int deps_may_trap_p (rtx mem) { rtx addr = XEXP (mem, 0); if (REG_P (addr) && REGNO (addr) >= FIRST_PSEUDO_REGISTER) { rtx t = get_reg_known_value (REGNO (addr)); if (t) addr = t; } return rtx_addr_can_trap_p (addr); } /* Return the INSN_LIST containing INSN in LIST, or NULL if LIST does not contain INSN. */ rtx find_insn_list (rtx insn, rtx list) { while (list) { if (XEXP (list, 0) == insn) return list; list = XEXP (list, 1); } return 0; } /* Find the condition under which INSN is executed. */ static rtx get_condition (rtx insn) { rtx pat = PATTERN (insn); rtx cond; if (pat == 0) return 0; if (GET_CODE (pat) == COND_EXEC) return COND_EXEC_TEST (pat); if (GET_CODE (insn) != JUMP_INSN) return 0; if (GET_CODE (pat) != SET || SET_SRC (pat) != pc_rtx) return 0; if (GET_CODE (SET_DEST (pat)) != IF_THEN_ELSE) return 0; pat = SET_DEST (pat); cond = XEXP (pat, 0); if (GET_CODE (XEXP (cond, 1)) == LABEL_REF && XEXP (cond, 2) == pc_rtx) return cond; else if (GET_CODE (XEXP (cond, 2)) == LABEL_REF && XEXP (cond, 1) == pc_rtx) return gen_rtx_fmt_ee (reverse_condition (GET_CODE (cond)), GET_MODE (cond), XEXP (cond, 0), XEXP (cond, 1)); else return 0; } /* Return nonzero if conditions COND1 and COND2 can never be both true. */ static int conditions_mutex_p (rtx cond1, rtx cond2) { if (GET_RTX_CLASS (GET_CODE (cond1)) == '<' && GET_RTX_CLASS (GET_CODE (cond2)) == '<' && GET_CODE (cond1) == reverse_condition (GET_CODE (cond2)) && XEXP (cond1, 0) == XEXP (cond2, 0) && XEXP (cond1, 1) == XEXP (cond2, 1)) return 1; return 0; } /* Add ELEM wrapped in an INSN_LIST with reg note kind DEP_TYPE to the LOG_LINKS of INSN, if not already there. DEP_TYPE indicates the type of dependence that this link represents. The function returns nonzero if a new entry has been added to insn's LOG_LINK. */ int add_dependence (rtx insn, rtx elem, enum reg_note dep_type) { rtx link; int present_p; rtx cond1, cond2; /* Don't depend an insn on itself. */ if (insn == elem) return 0; /* We can get a dependency on deleted insns due to optimizations in the register allocation and reloading or due to splitting. Any such dependency is useless and can be ignored. */ if (GET_CODE (elem) == NOTE) return 0; /* flow.c doesn't handle conditional lifetimes entirely correctly; calls mess up the conditional lifetimes. */ /* ??? add_dependence is the wrong place to be eliding dependencies, as that forgets that the condition expressions themselves may be dependent. */ if (GET_CODE (insn) != CALL_INSN && GET_CODE (elem) != CALL_INSN) { cond1 = get_condition (insn); cond2 = get_condition (elem); if (cond1 && cond2 && conditions_mutex_p (cond1, cond2) /* Make sure first instruction doesn't affect condition of second instruction if switched. */ && !modified_in_p (cond1, elem) /* Make sure second instruction doesn't affect condition of first instruction if switched. */ && !modified_in_p (cond2, insn)) return 0; } present_p = 1; #ifdef INSN_SCHEDULING /* ??? No good way to tell from here whether we're doing interblock scheduling. Possibly add another callback. */ #if 0 /* (This code is guarded by INSN_SCHEDULING, otherwise INSN_BB is undefined.) No need for interblock dependences with calls, since calls are not moved between blocks. Note: the edge where elem is a CALL is still required. */ if (GET_CODE (insn) == CALL_INSN && (INSN_BB (elem) != INSN_BB (insn))) return 0; #endif /* If we already have a dependency for ELEM, then we do not need to do anything. Avoiding the list walk below can cut compile times dramatically for some code. */ if (true_dependency_cache != NULL) { enum reg_note present_dep_type = 0; if (anti_dependency_cache == NULL || output_dependency_cache == NULL) abort (); if (bitmap_bit_p (&true_dependency_cache[INSN_LUID (insn)], INSN_LUID (elem))) /* Do nothing (present_set_type is already 0). */ ; else if (bitmap_bit_p (&anti_dependency_cache[INSN_LUID (insn)], INSN_LUID (elem))) present_dep_type = REG_DEP_ANTI; else if (bitmap_bit_p (&output_dependency_cache[INSN_LUID (insn)], INSN_LUID (elem))) present_dep_type = REG_DEP_OUTPUT; else present_p = 0; if (present_p && (int) dep_type >= (int) present_dep_type) return 0; } #endif /* Check that we don't already have this dependence. */ if (present_p) for (link = LOG_LINKS (insn); link; link = XEXP (link, 1)) if (XEXP (link, 0) == elem) { #ifdef INSN_SCHEDULING /* Clear corresponding cache entry because type of the link may be changed. */ if (true_dependency_cache != NULL) { if (REG_NOTE_KIND (link) == REG_DEP_ANTI) bitmap_clear_bit (&anti_dependency_cache[INSN_LUID (insn)], INSN_LUID (elem)); else if (REG_NOTE_KIND (link) == REG_DEP_OUTPUT && output_dependency_cache) bitmap_clear_bit (&output_dependency_cache[INSN_LUID (insn)], INSN_LUID (elem)); else abort (); } #endif /* If this is a more restrictive type of dependence than the existing one, then change the existing dependence to this type. */ if ((int) dep_type < (int) REG_NOTE_KIND (link)) PUT_REG_NOTE_KIND (link, dep_type); #ifdef INSN_SCHEDULING /* If we are adding a dependency to INSN's LOG_LINKs, then note that in the bitmap caches of dependency information. */ if (true_dependency_cache != NULL) { if ((int) REG_NOTE_KIND (link) == 0) bitmap_set_bit (&true_dependency_cache[INSN_LUID (insn)], INSN_LUID (elem)); else if (REG_NOTE_KIND (link) == REG_DEP_ANTI) bitmap_set_bit (&anti_dependency_cache[INSN_LUID (insn)], INSN_LUID (elem)); else if (REG_NOTE_KIND (link) == REG_DEP_OUTPUT) bitmap_set_bit (&output_dependency_cache[INSN_LUID (insn)], INSN_LUID (elem)); } #endif return 0; } /* Might want to check one level of transitivity to save conses. */ link = alloc_INSN_LIST (elem, LOG_LINKS (insn)); LOG_LINKS (insn) = link; /* Insn dependency, not data dependency. */ PUT_REG_NOTE_KIND (link, dep_type); #ifdef INSN_SCHEDULING /* If we are adding a dependency to INSN's LOG_LINKs, then note that in the bitmap caches of dependency information. */ if (true_dependency_cache != NULL) { if ((int) dep_type == 0) bitmap_set_bit (&true_dependency_cache[INSN_LUID (insn)], INSN_LUID (elem)); else if (dep_type == REG_DEP_ANTI) bitmap_set_bit (&anti_dependency_cache[INSN_LUID (insn)], INSN_LUID (elem)); else if (dep_type == REG_DEP_OUTPUT) bitmap_set_bit (&output_dependency_cache[INSN_LUID (insn)], INSN_LUID (elem)); } #endif return 1; } /* A convenience wrapper to operate on an entire list. */ static void add_dependence_list (rtx insn, rtx list, enum reg_note dep_type) { for (; list; list = XEXP (list, 1)) add_dependence (insn, XEXP (list, 0), dep_type); } /* Similar, but free *LISTP at the same time. */ static void add_dependence_list_and_free (rtx insn, rtx *listp, enum reg_note dep_type) { rtx list, next; for (list = *listp, *listp = NULL; list ; list = next) { next = XEXP (list, 1); add_dependence (insn, XEXP (list, 0), dep_type); free_INSN_LIST_node (list); } } /* Set SCHED_GROUP_P and care for the rest of the bookkeeping that goes along with that. */ static void set_sched_group_p (rtx insn) { rtx prev; SCHED_GROUP_P (insn) = 1; prev = prev_nonnote_insn (insn); add_dependence (insn, prev, REG_DEP_ANTI); } /* Process an insn's memory dependencies. There are four kinds of dependencies: (0) read dependence: read follows read (1) true dependence: read follows write (2) anti dependence: write follows read (3) output dependence: write follows write We are careful to build only dependencies which actually exist, and use transitivity to avoid building too many links. */ /* Add an INSN and MEM reference pair to a pending INSN_LIST and MEM_LIST. The MEM is a memory reference contained within INSN, which we are saving so that we can do memory aliasing on it. */ void add_insn_mem_dependence (struct deps *deps, rtx *insn_list, rtx *mem_list, rtx insn, rtx mem) { rtx link; link = alloc_INSN_LIST (insn, *insn_list); *insn_list = link; if (current_sched_info->use_cselib) { mem = shallow_copy_rtx (mem); XEXP (mem, 0) = cselib_subst_to_values (XEXP (mem, 0)); } link = alloc_EXPR_LIST (VOIDmode, canon_rtx (mem), *mem_list); *mem_list = link; deps->pending_lists_length++; } /* Make a dependency between every memory reference on the pending lists and INSN, thus flushing the pending lists. FOR_READ is true if emitting dependencies for a read operation, similarly with FOR_WRITE. */ static void flush_pending_lists (struct deps *deps, rtx insn, int for_read, int for_write) { if (for_write) { add_dependence_list_and_free (insn, &deps->pending_read_insns, REG_DEP_ANTI); free_EXPR_LIST_list (&deps->pending_read_mems); } add_dependence_list_and_free (insn, &deps->pending_write_insns, for_read ? REG_DEP_ANTI : REG_DEP_OUTPUT); free_EXPR_LIST_list (&deps->pending_write_mems); deps->pending_lists_length = 0; add_dependence_list_and_free (insn, &deps->last_pending_memory_flush, for_read ? REG_DEP_ANTI : REG_DEP_OUTPUT); deps->last_pending_memory_flush = alloc_INSN_LIST (insn, NULL_RTX); deps->pending_flush_length = 1; } /* Analyze a single SET, CLOBBER, PRE_DEC, POST_DEC, PRE_INC or POST_INC rtx, X, creating all dependencies generated by the write to the destination of X, and reads of everything mentioned. */ static void sched_analyze_1 (struct deps *deps, rtx x, rtx insn) { int regno; rtx dest = XEXP (x, 0); enum rtx_code code = GET_CODE (x); if (dest == 0) return; if (GET_CODE (dest) == PARALLEL) { int i; for (i = XVECLEN (dest, 0) - 1; i >= 0; i--) if (XEXP (XVECEXP (dest, 0, i), 0) != 0) sched_analyze_1 (deps, gen_rtx_CLOBBER (VOIDmode, XEXP (XVECEXP (dest, 0, i), 0)), insn); if (GET_CODE (x) == SET) sched_analyze_2 (deps, SET_SRC (x), insn); return; } while (GET_CODE (dest) == STRICT_LOW_PART || GET_CODE (dest) == SUBREG || GET_CODE (dest) == ZERO_EXTRACT || GET_CODE (dest) == SIGN_EXTRACT) { if (GET_CODE (dest) == STRICT_LOW_PART || GET_CODE (dest) == ZERO_EXTRACT || GET_CODE (dest) == SIGN_EXTRACT || read_modify_subreg_p (dest)) { /* These both read and modify the result. We must handle them as writes to get proper dependencies for following instructions. We must handle them as reads to get proper dependencies from this to previous instructions. Thus we need to call sched_analyze_2. */ sched_analyze_2 (deps, XEXP (dest, 0), insn); } if (GET_CODE (dest) == ZERO_EXTRACT || GET_CODE (dest) == SIGN_EXTRACT) { /* The second and third arguments are values read by this insn. */ sched_analyze_2 (deps, XEXP (dest, 1), insn); sched_analyze_2 (deps, XEXP (dest, 2), insn); } dest = XEXP (dest, 0); } if (GET_CODE (dest) == REG) { regno = REGNO (dest); /* A hard reg in a wide mode may really be multiple registers. If so, mark all of them just like the first. */ if (regno < FIRST_PSEUDO_REGISTER) { int i = HARD_REGNO_NREGS (regno, GET_MODE (dest)); if (code == SET) { while (--i >= 0) SET_REGNO_REG_SET (reg_pending_sets, regno + i); } else { while (--i >= 0) SET_REGNO_REG_SET (reg_pending_clobbers, regno + i); } } /* ??? Reload sometimes emits USEs and CLOBBERs of pseudos that it does not reload. Ignore these as they have served their purpose already. */ else if (regno >= deps->max_reg) { if (GET_CODE (PATTERN (insn)) != USE && GET_CODE (PATTERN (insn)) != CLOBBER) abort (); } else { if (code == SET) SET_REGNO_REG_SET (reg_pending_sets, regno); else SET_REGNO_REG_SET (reg_pending_clobbers, regno); /* Pseudos that are REG_EQUIV to something may be replaced by that during reloading. We need only add dependencies for the address in the REG_EQUIV note. */ if (!reload_completed && get_reg_known_equiv_p (regno)) { rtx t = get_reg_known_value (regno); if (GET_CODE (t) == MEM) sched_analyze_2 (deps, XEXP (t, 0), insn); } /* Don't let it cross a call after scheduling if it doesn't already cross one. */ if (REG_N_CALLS_CROSSED (regno) == 0) add_dependence_list (insn, deps->last_function_call, REG_DEP_ANTI); } } else if (GET_CODE (dest) == MEM) { /* Writing memory. */ rtx t = dest; if (current_sched_info->use_cselib) { t = shallow_copy_rtx (dest); cselib_lookup (XEXP (t, 0), Pmode, 1); XEXP (t, 0) = cselib_subst_to_values (XEXP (t, 0)); } t = canon_rtx (t); if (deps->pending_lists_length > MAX_PENDING_LIST_LENGTH) { /* Flush all pending reads and writes to prevent the pending lists from getting any larger. Insn scheduling runs too slowly when these lists get long. When compiling GCC with itself, this flush occurs 8 times for sparc, and 10 times for m88k using the default value of 32. */ flush_pending_lists (deps, insn, false, true); } else { rtx pending, pending_mem; pending = deps->pending_read_insns; pending_mem = deps->pending_read_mems; while (pending) { if (anti_dependence (XEXP (pending_mem, 0), t)) add_dependence (insn, XEXP (pending, 0), REG_DEP_ANTI); pending = XEXP (pending, 1); pending_mem = XEXP (pending_mem, 1); } pending = deps->pending_write_insns; pending_mem = deps->pending_write_mems; while (pending) { if (output_dependence (XEXP (pending_mem, 0), t)) add_dependence (insn, XEXP (pending, 0), REG_DEP_OUTPUT); pending = XEXP (pending, 1); pending_mem = XEXP (pending_mem, 1); } add_dependence_list (insn, deps->last_pending_memory_flush, REG_DEP_ANTI); add_insn_mem_dependence (deps, &deps->pending_write_insns, &deps->pending_write_mems, insn, dest); } sched_analyze_2 (deps, XEXP (dest, 0), insn); } /* Analyze reads. */ if (GET_CODE (x) == SET) sched_analyze_2 (deps, SET_SRC (x), insn); } /* Analyze the uses of memory and registers in rtx X in INSN. */ static void sched_analyze_2 (struct deps *deps, rtx x, rtx insn) { int i; int j; enum rtx_code code; const char *fmt; if (x == 0) return; code = GET_CODE (x); switch (code) { case CONST_INT: case CONST_DOUBLE: case CONST_VECTOR: case SYMBOL_REF: case CONST: case LABEL_REF: /* Ignore constants. Note that we must handle CONST_DOUBLE here because it may have a cc0_rtx in its CONST_DOUBLE_CHAIN field, but this does not mean that this insn is using cc0. */ return; #ifdef HAVE_cc0 case CC0: /* User of CC0 depends on immediately preceding insn. */ set_sched_group_p (insn); /* Don't move CC0 setter to another block (it can set up the same flag for previous CC0 users which is safe). */ CANT_MOVE (prev_nonnote_insn (insn)) = 1; return; #endif case REG: { int regno = REGNO (x); if (regno < FIRST_PSEUDO_REGISTER) { int i = HARD_REGNO_NREGS (regno, GET_MODE (x)); while (--i >= 0) SET_REGNO_REG_SET (reg_pending_uses, regno + i); } /* ??? Reload sometimes emits USEs and CLOBBERs of pseudos that it does not reload. Ignore these as they have served their purpose already. */ else if (regno >= deps->max_reg) { if (GET_CODE (PATTERN (insn)) != USE && GET_CODE (PATTERN (insn)) != CLOBBER) abort (); } else { SET_REGNO_REG_SET (reg_pending_uses, regno); /* Pseudos that are REG_EQUIV to something may be replaced by that during reloading. We need only add dependencies for the address in the REG_EQUIV note. */ if (!reload_completed && get_reg_known_equiv_p (regno)) { rtx t = get_reg_known_value (regno); if (GET_CODE (t) == MEM) sched_analyze_2 (deps, XEXP (t, 0), insn); } /* If the register does not already cross any calls, then add this insn to the sched_before_next_call list so that it will still not cross calls after scheduling. */ if (REG_N_CALLS_CROSSED (regno) == 0) deps->sched_before_next_call = alloc_INSN_LIST (insn, deps->sched_before_next_call); } return; } case MEM: { /* Reading memory. */ rtx u; rtx pending, pending_mem; rtx t = x; if (current_sched_info->use_cselib) { t = shallow_copy_rtx (t); cselib_lookup (XEXP (t, 0), Pmode, 1); XEXP (t, 0) = cselib_subst_to_values (XEXP (t, 0)); } t = canon_rtx (t); pending = deps->pending_read_insns; pending_mem = deps->pending_read_mems; while (pending) { if (read_dependence (XEXP (pending_mem, 0), t)) add_dependence (insn, XEXP (pending, 0), REG_DEP_ANTI); pending = XEXP (pending, 1); pending_mem = XEXP (pending_mem, 1); } pending = deps->pending_write_insns; pending_mem = deps->pending_write_mems; while (pending) { if (true_dependence (XEXP (pending_mem, 0), VOIDmode, t, rtx_varies_p)) add_dependence (insn, XEXP (pending, 0), 0); pending = XEXP (pending, 1); pending_mem = XEXP (pending_mem, 1); } for (u = deps->last_pending_memory_flush; u; u = XEXP (u, 1)) if (GET_CODE (XEXP (u, 0)) != JUMP_INSN || deps_may_trap_p (x)) add_dependence (insn, XEXP (u, 0), REG_DEP_ANTI); /* Always add these dependencies to pending_reads, since this insn may be followed by a write. */ add_insn_mem_dependence (deps, &deps->pending_read_insns, &deps->pending_read_mems, insn, x); /* Take advantage of tail recursion here. */ sched_analyze_2 (deps, XEXP (x, 0), insn); return; } /* Force pending stores to memory in case a trap handler needs them. */ case TRAP_IF: flush_pending_lists (deps, insn, true, false); break; case ASM_OPERANDS: case ASM_INPUT: case UNSPEC_VOLATILE: { /* Traditional and volatile asm instructions must be considered to use and clobber all hard registers, all pseudo-registers and all of memory. So must TRAP_IF and UNSPEC_VOLATILE operations. Consider for instance a volatile asm that changes the fpu rounding mode. An insn should not be moved across this even if it only uses pseudo-regs because it might give an incorrectly rounded result. */ if (code != ASM_OPERANDS || MEM_VOLATILE_P (x)) reg_pending_barrier = TRUE_BARRIER; /* For all ASM_OPERANDS, we must traverse the vector of input operands. We can not just fall through here since then we would be confused by the ASM_INPUT rtx inside ASM_OPERANDS, which do not indicate traditional asms unlike their normal usage. */ if (code == ASM_OPERANDS) { for (j = 0; j < ASM_OPERANDS_INPUT_LENGTH (x); j++) sched_analyze_2 (deps, ASM_OPERANDS_INPUT (x, j), insn); return; } break; } case PRE_DEC: case POST_DEC: case PRE_INC: case POST_INC: /* These both read and modify the result. We must handle them as writes to get proper dependencies for following instructions. We must handle them as reads to get proper dependencies from this to previous instructions. Thus we need to pass them to both sched_analyze_1 and sched_analyze_2. We must call sched_analyze_2 first in order to get the proper antecedent for the read. */ sched_analyze_2 (deps, XEXP (x, 0), insn); sched_analyze_1 (deps, x, insn); return; case POST_MODIFY: case PRE_MODIFY: /* op0 = op0 + op1 */ sched_analyze_2 (deps, XEXP (x, 0), insn); sched_analyze_2 (deps, XEXP (x, 1), insn); sched_analyze_1 (deps, x, insn); return; default: break; } /* Other cases: walk the insn. */ fmt = GET_RTX_FORMAT (code); for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--) { if (fmt[i] == 'e') sched_analyze_2 (deps, XEXP (x, i), insn); else if (fmt[i] == 'E') for (j = 0; j < XVECLEN (x, i); j++) sched_analyze_2 (deps, XVECEXP (x, i, j), insn); } } /* Analyze an INSN with pattern X to find all dependencies. */ static void sched_analyze_insn (struct deps *deps, rtx x, rtx insn, rtx loop_notes) { RTX_CODE code = GET_CODE (x); rtx link; int i; if (code == COND_EXEC) { sched_analyze_2 (deps, COND_EXEC_TEST (x), insn); /* ??? Should be recording conditions so we reduce the number of false dependencies. */ x = COND_EXEC_CODE (x); code = GET_CODE (x); } if (code == SET || code == CLOBBER) { sched_analyze_1 (deps, x, insn); /* Bare clobber insns are used for letting life analysis, reg-stack and others know that a value is dead. Depend on the last call instruction so that reg-stack won't get confused. */ if (code == CLOBBER) add_dependence_list (insn, deps->last_function_call, REG_DEP_OUTPUT); } else if (code == PARALLEL) { int i; for (i = XVECLEN (x, 0) - 1; i >= 0; i--) { rtx sub = XVECEXP (x, 0, i); code = GET_CODE (sub); if (code == COND_EXEC) { sched_analyze_2 (deps, COND_EXEC_TEST (sub), insn); sub = COND_EXEC_CODE (sub); code = GET_CODE (sub); } if (code == SET || code == CLOBBER) sched_analyze_1 (deps, sub, insn); else sched_analyze_2 (deps, sub, insn); } } else sched_analyze_2 (deps, x, insn); /* Mark registers CLOBBERED or used by called function. */ if (GET_CODE (insn) == CALL_INSN) { for (link = CALL_INSN_FUNCTION_USAGE (insn); link; link = XEXP (link, 1)) { if (GET_CODE (XEXP (link, 0)) == CLOBBER) sched_analyze_1 (deps, XEXP (link, 0), insn); else sched_analyze_2 (deps, XEXP (link, 0), insn); } if (find_reg_note (insn, REG_SETJMP, NULL)) reg_pending_barrier = MOVE_BARRIER; } if (GET_CODE (insn) == JUMP_INSN) { rtx next; next = next_nonnote_insn (insn); if (next && GET_CODE (next) == BARRIER) reg_pending_barrier = TRUE_BARRIER; else { rtx pending, pending_mem; regset_head tmp_uses, tmp_sets; INIT_REG_SET (&tmp_uses); INIT_REG_SET (&tmp_sets); (*current_sched_info->compute_jump_reg_dependencies) (insn, &deps->reg_conditional_sets, &tmp_uses, &tmp_sets); /* Make latency of jump equal to 0 by using anti-dependence. */ EXECUTE_IF_SET_IN_REG_SET (&tmp_uses, 0, i, { struct deps_reg *reg_last = &deps->reg_last[i]; add_dependence_list (insn, reg_last->sets, REG_DEP_ANTI); add_dependence_list (insn, reg_last->clobbers, REG_DEP_ANTI); reg_last->uses_length++; reg_last->uses = alloc_INSN_LIST (insn, reg_last->uses); }); IOR_REG_SET (reg_pending_sets, &tmp_sets); CLEAR_REG_SET (&tmp_uses); CLEAR_REG_SET (&tmp_sets); /* All memory writes and volatile reads must happen before the jump. Non-volatile reads must happen before the jump iff the result is needed by the above register used mask. */ pending = deps->pending_write_insns; pending_mem = deps->pending_write_mems; while (pending) { add_dependence (insn, XEXP (pending, 0), REG_DEP_OUTPUT); pending = XEXP (pending, 1); pending_mem = XEXP (pending_mem, 1); } pending = deps->pending_read_insns; pending_mem = deps->pending_read_mems; while (pending) { if (MEM_VOLATILE_P (XEXP (pending_mem, 0))) add_dependence (insn, XEXP (pending, 0), REG_DEP_OUTPUT); pending = XEXP (pending, 1); pending_mem = XEXP (pending_mem, 1); } add_dependence_list (insn, deps->last_pending_memory_flush, REG_DEP_ANTI); } } /* If there is a {LOOP,EHREGION}_{BEG,END} note in the middle of a basic block, then we must be sure that no instructions are scheduled across it. Otherwise, the reg_n_refs info (which depends on loop_depth) would become incorrect. */ if (loop_notes) { rtx link; /* Update loop_notes with any notes from this insn. Also determine if any of the notes on the list correspond to instruction scheduling barriers (loop, eh & setjmp notes, but not range notes). */ link = loop_notes; while (XEXP (link, 1)) { if (INTVAL (XEXP (link, 0)) == NOTE_INSN_LOOP_BEG || INTVAL (XEXP (link, 0)) == NOTE_INSN_LOOP_END || INTVAL (XEXP (link, 0)) == NOTE_INSN_EH_REGION_BEG || INTVAL (XEXP (link, 0)) == NOTE_INSN_EH_REGION_END) reg_pending_barrier = MOVE_BARRIER; link = XEXP (link, 1); } XEXP (link, 1) = REG_NOTES (insn); REG_NOTES (insn) = loop_notes; } /* If this instruction can throw an exception, then moving it changes where block boundaries fall. This is mighty confusing elsewhere. Therefore, prevent such an instruction from being moved. */ if (can_throw_internal (insn)) reg_pending_barrier = MOVE_BARRIER; /* Add dependencies if a scheduling barrier was found. */ if (reg_pending_barrier) { /* In the case of barrier the most added dependencies are not real, so we use anti-dependence here. */ if (GET_CODE (PATTERN (insn)) == COND_EXEC) { EXECUTE_IF_SET_IN_REG_SET (&deps->reg_last_in_use, 0, i, { struct deps_reg *reg_last = &deps->reg_last[i]; add_dependence_list (insn, reg_last->uses, REG_DEP_ANTI); add_dependence_list (insn, reg_last->sets, reg_pending_barrier == TRUE_BARRIER ? 0 : REG_DEP_ANTI); add_dependence_list (insn, reg_last->clobbers, reg_pending_barrier == TRUE_BARRIER ? 0 : REG_DEP_ANTI); }); } else { EXECUTE_IF_SET_IN_REG_SET (&deps->reg_last_in_use, 0, i, { struct deps_reg *reg_last = &deps->reg_last[i]; add_dependence_list_and_free (insn, ®_last->uses, REG_DEP_ANTI); add_dependence_list_and_free (insn, ®_last->sets, reg_pending_barrier == TRUE_BARRIER ? 0 : REG_DEP_ANTI); add_dependence_list_and_free (insn, ®_last->clobbers, reg_pending_barrier == TRUE_BARRIER ? 0 : REG_DEP_ANTI); reg_last->uses_length = 0; reg_last->clobbers_length = 0; }); } for (i = 0; i < deps->max_reg; i++) { struct deps_reg *reg_last = &deps->reg_last[i]; reg_last->sets = alloc_INSN_LIST (insn, reg_last->sets); SET_REGNO_REG_SET (&deps->reg_last_in_use, i); } flush_pending_lists (deps, insn, true, true); CLEAR_REG_SET (&deps->reg_conditional_sets); reg_pending_barrier = NOT_A_BARRIER; } else { /* If the current insn is conditional, we can't free any of the lists. */ if (GET_CODE (PATTERN (insn)) == COND_EXEC) { EXECUTE_IF_SET_IN_REG_SET (reg_pending_uses, 0, i, { struct deps_reg *reg_last = &deps->reg_last[i]; add_dependence_list (insn, reg_last->sets, 0); add_dependence_list (insn, reg_last->clobbers, 0); reg_last->uses = alloc_INSN_LIST (insn, reg_last->uses); reg_last->uses_length++; }); EXECUTE_IF_SET_IN_REG_SET (reg_pending_clobbers, 0, i, { struct deps_reg *reg_last = &deps->reg_last[i]; add_dependence_list (insn, reg_last->sets, REG_DEP_OUTPUT); add_dependence_list (insn, reg_last->uses, REG_DEP_ANTI); reg_last->clobbers = alloc_INSN_LIST (insn, reg_last->clobbers); reg_last->clobbers_length++; }); EXECUTE_IF_SET_IN_REG_SET (reg_pending_sets, 0, i, { struct deps_reg *reg_last = &deps->reg_last[i]; add_dependence_list (insn, reg_last->sets, REG_DEP_OUTPUT); add_dependence_list (insn, reg_last->clobbers, REG_DEP_OUTPUT); add_dependence_list (insn, reg_last->uses, REG_DEP_ANTI); reg_last->sets = alloc_INSN_LIST (insn, reg_last->sets); SET_REGNO_REG_SET (&deps->reg_conditional_sets, i); }); } else { EXECUTE_IF_SET_IN_REG_SET (reg_pending_uses, 0, i, { struct deps_reg *reg_last = &deps->reg_last[i]; add_dependence_list (insn, reg_last->sets, 0); add_dependence_list (insn, reg_last->clobbers, 0); reg_last->uses_length++; reg_last->uses = alloc_INSN_LIST (insn, reg_last->uses); }); EXECUTE_IF_SET_IN_REG_SET (reg_pending_clobbers, 0, i, { struct deps_reg *reg_last = &deps->reg_last[i]; if (reg_last->uses_length > MAX_PENDING_LIST_LENGTH || reg_last->clobbers_length > MAX_PENDING_LIST_LENGTH) { add_dependence_list_and_free (insn, ®_last->sets, REG_DEP_OUTPUT); add_dependence_list_and_free (insn, ®_last->uses, REG_DEP_ANTI); add_dependence_list_and_free (insn, ®_last->clobbers, REG_DEP_OUTPUT); reg_last->sets = alloc_INSN_LIST (insn, reg_last->sets); reg_last->clobbers_length = 0; reg_last->uses_length = 0; } else { add_dependence_list (insn, reg_last->sets, REG_DEP_OUTPUT); add_dependence_list (insn, reg_last->uses, REG_DEP_ANTI); } reg_last->clobbers_length++; reg_last->clobbers = alloc_INSN_LIST (insn, reg_last->clobbers); }); EXECUTE_IF_SET_IN_REG_SET (reg_pending_sets, 0, i, { struct deps_reg *reg_last = &deps->reg_last[i]; add_dependence_list_and_free (insn, ®_last->sets, REG_DEP_OUTPUT); add_dependence_list_and_free (insn, ®_last->clobbers, REG_DEP_OUTPUT); add_dependence_list_and_free (insn, ®_last->uses, REG_DEP_ANTI); reg_last->sets = alloc_INSN_LIST (insn, reg_last->sets); reg_last->uses_length = 0; reg_last->clobbers_length = 0; CLEAR_REGNO_REG_SET (&deps->reg_conditional_sets, i); }); } IOR_REG_SET (&deps->reg_last_in_use, reg_pending_uses); IOR_REG_SET (&deps->reg_last_in_use, reg_pending_clobbers); IOR_REG_SET (&deps->reg_last_in_use, reg_pending_sets); } CLEAR_REG_SET (reg_pending_uses); CLEAR_REG_SET (reg_pending_clobbers); CLEAR_REG_SET (reg_pending_sets); /* If we are currently in a libcall scheduling group, then mark the current insn as being in a scheduling group and that it can not be moved into a different basic block. */ if (deps->libcall_block_tail_insn) { set_sched_group_p (insn); CANT_MOVE (insn) = 1; } /* If a post-call group is still open, see if it should remain so. This insn must be a simple move of a hard reg to a pseudo or vice-versa. We must avoid moving these insns for correctness on SMALL_REGISTER_CLASS machines, and for special registers like PIC_OFFSET_TABLE_REGNUM. For simplicity, extend this to all hard regs for all targets. */ if (deps->in_post_call_group_p) { rtx tmp, set = single_set (insn); int src_regno, dest_regno; if (set == NULL) goto end_call_group; tmp = SET_DEST (set); if (GET_CODE (tmp) == SUBREG) tmp = SUBREG_REG (tmp); if (GET_CODE (tmp) == REG) dest_regno = REGNO (tmp); else goto end_call_group; tmp = SET_SRC (set); if (GET_CODE (tmp) == SUBREG) tmp = SUBREG_REG (tmp); if (GET_CODE (tmp) == REG) src_regno = REGNO (tmp); else goto end_call_group; if (src_regno < FIRST_PSEUDO_REGISTER || dest_regno < FIRST_PSEUDO_REGISTER) { set_sched_group_p (insn); CANT_MOVE (insn) = 1; } else { end_call_group: deps->in_post_call_group_p = false; } } } /* Analyze every insn between HEAD and TAIL inclusive, creating LOG_LINKS for every dependency. */ void sched_analyze (struct deps *deps, rtx head, rtx tail) { rtx insn; rtx loop_notes = 0; if (current_sched_info->use_cselib) cselib_init (); for (insn = head;; insn = NEXT_INSN (insn)) { rtx link, end_seq, r0, set; if (GET_CODE (insn) == INSN || GET_CODE (insn) == JUMP_INSN) { /* Clear out the stale LOG_LINKS from flow. */ free_INSN_LIST_list (&LOG_LINKS (insn)); /* Make each JUMP_INSN a scheduling barrier for memory references. */ if (GET_CODE (insn) == JUMP_INSN) { /* Keep the list a reasonable size. */ if (deps->pending_flush_length++ > MAX_PENDING_LIST_LENGTH) flush_pending_lists (deps, insn, true, true); else deps->last_pending_memory_flush = alloc_INSN_LIST (insn, deps->last_pending_memory_flush); } sched_analyze_insn (deps, PATTERN (insn), insn, loop_notes); loop_notes = 0; } else if (GET_CODE (insn) == CALL_INSN) { int i; CANT_MOVE (insn) = 1; /* Clear out the stale LOG_LINKS from flow. */ free_INSN_LIST_list (&LOG_LINKS (insn)); if (find_reg_note (insn, REG_SETJMP, NULL)) { /* This is setjmp. Assume that all registers, not just hard registers, may be clobbered by this call. */ reg_pending_barrier = MOVE_BARRIER; } else { for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) /* A call may read and modify global register variables. */ if (global_regs[i]) { SET_REGNO_REG_SET (reg_pending_sets, i); SET_REGNO_REG_SET (reg_pending_uses, i); } /* Other call-clobbered hard regs may be clobbered. Since we only have a choice between 'might be clobbered' and 'definitely not clobbered', we must include all partly call-clobbered registers here. */ else if (HARD_REGNO_CALL_PART_CLOBBERED (i, reg_raw_mode[i]) || TEST_HARD_REG_BIT (regs_invalidated_by_call, i)) SET_REGNO_REG_SET (reg_pending_clobbers, i); /* We don't know what set of fixed registers might be used by the function, but it is certain that the stack pointer is among them, but be conservative. */ else if (fixed_regs[i]) SET_REGNO_REG_SET (reg_pending_uses, i); /* The frame pointer is normally not used by the function itself, but by the debugger. */ /* ??? MIPS o32 is an exception. It uses the frame pointer in the macro expansion of jal but does not represent this fact in the call_insn rtl. */ else if (i == FRAME_POINTER_REGNUM || (i == HARD_FRAME_POINTER_REGNUM && (! reload_completed || frame_pointer_needed))) SET_REGNO_REG_SET (reg_pending_uses, i); } /* For each insn which shouldn't cross a call, add a dependence between that insn and this call insn. */ add_dependence_list_and_free (insn, &deps->sched_before_next_call, REG_DEP_ANTI); sched_analyze_insn (deps, PATTERN (insn), insn, loop_notes); loop_notes = 0; /* In the absence of interprocedural alias analysis, we must flush all pending reads and writes, and start new dependencies starting from here. But only flush writes for constant calls (which may be passed a pointer to something we haven't written yet). */ flush_pending_lists (deps, insn, true, !CONST_OR_PURE_CALL_P (insn)); /* Remember the last function call for limiting lifetimes. */ free_INSN_LIST_list (&deps->last_function_call); deps->last_function_call = alloc_INSN_LIST (insn, NULL_RTX); /* Before reload, begin a post-call group, so as to keep the lifetimes of hard registers correct. */ if (! reload_completed) deps->in_post_call_group_p = true; } /* See comments on reemit_notes as to why we do this. ??? Actually, the reemit_notes just say what is done, not why. */ if (GET_CODE (insn) == NOTE && (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG || NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_END || NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_BEG || NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_END)) { rtx rtx_region; if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_BEG || NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_END) rtx_region = GEN_INT (NOTE_EH_HANDLER (insn)); else rtx_region = GEN_INT (0); loop_notes = alloc_EXPR_LIST (REG_SAVE_NOTE, rtx_region, loop_notes); loop_notes = alloc_EXPR_LIST (REG_SAVE_NOTE, GEN_INT (NOTE_LINE_NUMBER (insn)), loop_notes); CONST_OR_PURE_CALL_P (loop_notes) = CONST_OR_PURE_CALL_P (insn); } if (current_sched_info->use_cselib) cselib_process_insn (insn); /* Now that we have completed handling INSN, check and see if it is a CLOBBER beginning a libcall block. If it is, record the end of the libcall sequence. We want to schedule libcall blocks as a unit before reload. While this restricts scheduling, it preserves the meaning of a libcall block. As a side effect, we may get better code due to decreased register pressure as well as less chance of a foreign insn appearing in a libcall block. */ if (!reload_completed /* Note we may have nested libcall sequences. We only care about the outermost libcall sequence. */ && deps->libcall_block_tail_insn == 0 /* The sequence must start with a clobber of a register. */ && GET_CODE (insn) == INSN && GET_CODE (PATTERN (insn)) == CLOBBER && (r0 = XEXP (PATTERN (insn), 0), GET_CODE (r0) == REG) && GET_CODE (XEXP (PATTERN (insn), 0)) == REG /* The CLOBBER must also have a REG_LIBCALL note attached. */ && (link = find_reg_note (insn, REG_LIBCALL, NULL_RTX)) != 0 && (end_seq = XEXP (link, 0)) != 0 /* The insn referenced by the REG_LIBCALL note must be a simple nop copy with the same destination as the register mentioned in the clobber. */ && (set = single_set (end_seq)) != 0 && SET_DEST (set) == r0 && SET_SRC (set) == r0 /* And finally the insn referenced by the REG_LIBCALL must also contain a REG_EQUAL note and a REG_RETVAL note. */ && find_reg_note (end_seq, REG_EQUAL, NULL_RTX) != 0 && find_reg_note (end_seq, REG_RETVAL, NULL_RTX) != 0) deps->libcall_block_tail_insn = XEXP (link, 0); /* If we have reached the end of a libcall block, then close the block. */ if (deps->libcall_block_tail_insn == insn) deps->libcall_block_tail_insn = 0; if (insn == tail) { if (current_sched_info->use_cselib) cselib_finish (); return; } } abort (); } /* The following function adds forward dependence (FROM, TO) with given DEP_TYPE. The forward dependence should be not exist before. */ void add_forward_dependence (rtx from, rtx to, enum reg_note dep_type) { rtx new_link; #ifdef ENABLE_CHECKING /* If add_dependence is working properly there should never be notes, deleted insns or duplicates in the backward links. Thus we need not check for them here. However, if we have enabled checking we might as well go ahead and verify that add_dependence worked properly. */ if (GET_CODE (from) == NOTE || INSN_DELETED_P (from) || (forward_dependency_cache != NULL && bitmap_bit_p (&forward_dependency_cache[INSN_LUID (from)], INSN_LUID (to))) || (forward_dependency_cache == NULL && find_insn_list (to, INSN_DEPEND (from)))) abort (); if (forward_dependency_cache != NULL) bitmap_bit_p (&forward_dependency_cache[INSN_LUID (from)], INSN_LUID (to)); #endif new_link = alloc_INSN_LIST (to, INSN_DEPEND (from)); PUT_REG_NOTE_KIND (new_link, dep_type); INSN_DEPEND (from) = new_link; INSN_DEP_COUNT (to) += 1; } /* Examine insns in the range [ HEAD, TAIL ] and Use the backward dependences from LOG_LINKS to build forward dependences in INSN_DEPEND. */ void compute_forward_dependences (rtx head, rtx tail) { rtx insn, link; rtx next_tail; next_tail = NEXT_INSN (tail); for (insn = head; insn != next_tail; insn = NEXT_INSN (insn)) { if (! INSN_P (insn)) continue; for (link = LOG_LINKS (insn); link; link = XEXP (link, 1)) add_forward_dependence (XEXP (link, 0), insn, REG_NOTE_KIND (link)); } } /* Initialize variables for region data dependence analysis. n_bbs is the number of region blocks. */ void init_deps (struct deps *deps) { int max_reg = (reload_completed ? FIRST_PSEUDO_REGISTER : max_reg_num ()); deps->max_reg = max_reg; deps->reg_last = xcalloc (max_reg, sizeof (struct deps_reg)); INIT_REG_SET (&deps->reg_last_in_use); INIT_REG_SET (&deps->reg_conditional_sets); deps->pending_read_insns = 0; deps->pending_read_mems = 0; deps->pending_write_insns = 0; deps->pending_write_mems = 0; deps->pending_lists_length = 0; deps->pending_flush_length = 0; deps->last_pending_memory_flush = 0; deps->last_function_call = 0; deps->sched_before_next_call = 0; deps->in_post_call_group_p = false; deps->libcall_block_tail_insn = 0; } /* Free insn lists found in DEPS. */ void free_deps (struct deps *deps) { int i; free_INSN_LIST_list (&deps->pending_read_insns); free_EXPR_LIST_list (&deps->pending_read_mems); free_INSN_LIST_list (&deps->pending_write_insns); free_EXPR_LIST_list (&deps->pending_write_mems); free_INSN_LIST_list (&deps->last_pending_memory_flush); /* Without the EXECUTE_IF_SET, this loop is executed max_reg * nr_regions times. For a testcase with 42000 regs and 8000 small basic blocks, this loop accounted for nearly 60% (84 sec) of the total -O2 runtime. */ EXECUTE_IF_SET_IN_REG_SET (&deps->reg_last_in_use, 0, i, { struct deps_reg *reg_last = &deps->reg_last[i]; if (reg_last->uses) free_INSN_LIST_list (®_last->uses); if (reg_last->sets) free_INSN_LIST_list (®_last->sets); if (reg_last->clobbers) free_INSN_LIST_list (®_last->clobbers); }); CLEAR_REG_SET (&deps->reg_last_in_use); CLEAR_REG_SET (&deps->reg_conditional_sets); free (deps->reg_last); } /* If it is profitable to use them, initialize caches for tracking dependency information. LUID is the number of insns to be scheduled, it is used in the estimate of profitability. */ void init_dependency_caches (int luid) { /* ?!? We could save some memory by computing a per-region luid mapping which could reduce both the number of vectors in the cache and the size of each vector. Instead we just avoid the cache entirely unless the average number of instructions in a basic block is very high. See the comment before the declaration of true_dependency_cache for what we consider "very high". */ if (luid / n_basic_blocks > 100 * 5) { int i; true_dependency_cache = xmalloc (luid * sizeof (bitmap_head)); anti_dependency_cache = xmalloc (luid * sizeof (bitmap_head)); output_dependency_cache = xmalloc (luid * sizeof (bitmap_head)); #ifdef ENABLE_CHECKING forward_dependency_cache = xmalloc (luid * sizeof (bitmap_head)); #endif for (i = 0; i < luid; i++) { bitmap_initialize (&true_dependency_cache[i], 0); bitmap_initialize (&anti_dependency_cache[i], 0); bitmap_initialize (&output_dependency_cache[i], 0); #ifdef ENABLE_CHECKING bitmap_initialize (&forward_dependency_cache[i], 0); #endif } cache_size = luid; } } /* Free the caches allocated in init_dependency_caches. */ void free_dependency_caches (void) { if (true_dependency_cache) { int i; for (i = 0; i < cache_size; i++) { bitmap_clear (&true_dependency_cache[i]); bitmap_clear (&anti_dependency_cache[i]); bitmap_clear (&output_dependency_cache[i]); #ifdef ENABLE_CHECKING bitmap_clear (&forward_dependency_cache[i]); #endif } free (true_dependency_cache); true_dependency_cache = NULL; free (anti_dependency_cache); anti_dependency_cache = NULL; free (output_dependency_cache); output_dependency_cache = NULL; #ifdef ENABLE_CHECKING free (forward_dependency_cache); forward_dependency_cache = NULL; #endif } } /* Initialize some global variables needed by the dependency analysis code. */ void init_deps_global (void) { reg_pending_sets = INITIALIZE_REG_SET (reg_pending_sets_head); reg_pending_clobbers = INITIALIZE_REG_SET (reg_pending_clobbers_head); reg_pending_uses = INITIALIZE_REG_SET (reg_pending_uses_head); reg_pending_barrier = NOT_A_BARRIER; } /* Free everything used by the dependency analysis code. */ void finish_deps_global (void) { FREE_REG_SET (reg_pending_sets); FREE_REG_SET (reg_pending_clobbers); FREE_REG_SET (reg_pending_uses); }