/* Allocate registers for pseudo-registers that span basic blocks. Copyright (C) 1987, 88, 91, 94, 96, 1997 Free Software Foundation, Inc. This file is part of GNU CC. GNU CC 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. GNU CC 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 GNU CC; 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 #ifdef HAVE_STDLIB_H #include #endif #include "rtl.h" #include "flags.h" #include "basic-block.h" #include "hard-reg-set.h" #include "regs.h" #include "insn-config.h" #include "output.h" /* This pass of the compiler performs global register allocation. It assigns hard register numbers to all the pseudo registers that were not handled in local_alloc. Assignments are recorded in the vector reg_renumber, not by changing the rtl code. (Such changes are made by final). The entry point is the function global_alloc. After allocation is complete, the reload pass is run as a subroutine of this pass, so that when a pseudo reg loses its hard reg due to spilling it is possible to make a second attempt to find a hard reg for it. The reload pass is independent in other respects and it is run even when stupid register allocation is in use. 1. count the pseudo-registers still needing allocation and assign allocation-numbers (allocnos) to them. Set up tables reg_allocno and allocno_reg to map reg numbers to allocnos and vice versa. max_allocno gets the number of allocnos in use. 2. Allocate a max_allocno by max_allocno conflict bit matrix and clear it. Allocate a max_allocno by FIRST_PSEUDO_REGISTER conflict matrix for conflicts between allocnos and explicit hard register use (which includes use of pseudo-registers allocated by local_alloc). 3. for each basic block walk forward through the block, recording which unallocated registers and which hardware registers are live. Build the conflict matrix between the unallocated registers and another of unallocated registers versus hardware registers. Also record the preferred hardware registers for each unallocated one. 4. Sort a table of the allocnos into order of desirability of the variables. 5. Allocate the variables in that order; each if possible into a preferred register, else into another register. */ /* Number of pseudo-registers still requiring allocation (not allocated by local_allocate). */ static int max_allocno; /* Indexed by (pseudo) reg number, gives the allocno, or -1 for pseudo registers already allocated by local_allocate. */ int *reg_allocno; /* Indexed by allocno, gives the reg number. */ static int *allocno_reg; /* A vector of the integers from 0 to max_allocno-1, sorted in the order of first-to-be-allocated first. */ static int *allocno_order; /* Indexed by an allocno, gives the number of consecutive hard registers needed by that pseudo reg. */ static int *allocno_size; /* Indexed by (pseudo) reg number, gives the number of another lower-numbered pseudo reg which can share a hard reg with this pseudo *even if the two pseudos would otherwise appear to conflict*. */ static int *reg_may_share; /* Define the number of bits in each element of `conflicts' and what type that element has. We use the largest integer format on the host machine. */ #define INT_BITS HOST_BITS_PER_WIDE_INT #define INT_TYPE HOST_WIDE_INT /* max_allocno by max_allocno array of bits, recording whether two allocno's conflict (can't go in the same hardware register). `conflicts' is not symmetric; a conflict between allocno's i and j is recorded either in element i,j or in element j,i. */ static INT_TYPE *conflicts; /* Number of ints require to hold max_allocno bits. This is the length of a row in `conflicts'. */ static int allocno_row_words; /* Two macros to test or store 1 in an element of `conflicts'. */ #define CONFLICTP(I, J) \ (conflicts[(I) * allocno_row_words + (J) / INT_BITS] \ & ((INT_TYPE) 1 << ((J) % INT_BITS))) #define SET_CONFLICT(I, J) \ (conflicts[(I) * allocno_row_words + (J) / INT_BITS] \ |= ((INT_TYPE) 1 << ((J) % INT_BITS))) /* Set of hard regs currently live (during scan of all insns). */ static HARD_REG_SET hard_regs_live; /* Indexed by N, set of hard regs conflicting with allocno N. */ static HARD_REG_SET *hard_reg_conflicts; /* Indexed by N, set of hard regs preferred by allocno N. This is used to make allocnos go into regs that are copied to or from them, when possible, to reduce register shuffling. */ static HARD_REG_SET *hard_reg_preferences; /* Similar, but just counts register preferences made in simple copy operations, rather than arithmetic. These are given priority because we can always eliminate an insn by using these, but using a register in the above list won't always eliminate an insn. */ static HARD_REG_SET *hard_reg_copy_preferences; /* Similar to hard_reg_preferences, but includes bits for subsequent registers when an allocno is multi-word. The above variable is used for allocation while this is used to build reg_someone_prefers, below. */ static HARD_REG_SET *hard_reg_full_preferences; /* Indexed by N, set of hard registers that some later allocno has a preference for. */ static HARD_REG_SET *regs_someone_prefers; /* Set of registers that global-alloc isn't supposed to use. */ static HARD_REG_SET no_global_alloc_regs; /* Set of registers used so far. */ static HARD_REG_SET regs_used_so_far; /* Number of calls crossed by each allocno. */ static int *allocno_calls_crossed; /* Number of refs (weighted) to each allocno. */ static int *allocno_n_refs; /* Guess at live length of each allocno. This is actually the max of the live lengths of the regs. */ static int *allocno_live_length; /* Number of refs (weighted) to each hard reg, as used by local alloc. It is zero for a reg that contains global pseudos or is explicitly used. */ static int local_reg_n_refs[FIRST_PSEUDO_REGISTER]; /* Guess at live length of each hard reg, as used by local alloc. This is actually the sum of the live lengths of the specific regs. */ static int local_reg_live_length[FIRST_PSEUDO_REGISTER]; /* Test a bit in TABLE, a vector of HARD_REG_SETs, for vector element I, and hard register number J. */ #define REGBITP(TABLE, I, J) TEST_HARD_REG_BIT (TABLE[I], J) /* Set to 1 a bit in a vector of HARD_REG_SETs. Works like REGBITP. */ #define SET_REGBIT(TABLE, I, J) SET_HARD_REG_BIT (TABLE[I], J) /* Bit mask for allocnos live at current point in the scan. */ static INT_TYPE *allocnos_live; /* Test, set or clear bit number I in allocnos_live, a bit vector indexed by allocno. */ #define ALLOCNO_LIVE_P(I) \ (allocnos_live[(I) / INT_BITS] & ((INT_TYPE) 1 << ((I) % INT_BITS))) #define SET_ALLOCNO_LIVE(I) \ (allocnos_live[(I) / INT_BITS] |= ((INT_TYPE) 1 << ((I) % INT_BITS))) #define CLEAR_ALLOCNO_LIVE(I) \ (allocnos_live[(I) / INT_BITS] &= ~((INT_TYPE) 1 << ((I) % INT_BITS))) /* This is turned off because it doesn't work right for DImode. (And it is only used for DImode, so the other cases are worthless.) The problem is that it isn't true that there is NO possibility of conflict; only that there is no conflict if the two pseudos get the exact same regs. If they were allocated with a partial overlap, there would be a conflict. We can't safely turn off the conflict unless we have another way to prevent the partial overlap. Idea: change hard_reg_conflicts so that instead of recording which hard regs the allocno may not overlap, it records where the allocno may not start. Change both where it is used and where it is updated. Then there is a way to record that (reg:DI 108) may start at 10 but not at 9 or 11. There is still the question of how to record this semi-conflict between two pseudos. */ #if 0 /* Reg pairs for which conflict after the current insn is inhibited by a REG_NO_CONFLICT note. If the table gets full, we ignore any other notes--that is conservative. */ #define NUM_NO_CONFLICT_PAIRS 4 /* Number of pairs in use in this insn. */ int n_no_conflict_pairs; static struct { int allocno1, allocno2;} no_conflict_pairs[NUM_NO_CONFLICT_PAIRS]; #endif /* 0 */ /* Record all regs that are set in any one insn. Communication from mark_reg_{store,clobber} and global_conflicts. */ static rtx *regs_set; static int n_regs_set; /* All registers that can be eliminated. */ static HARD_REG_SET eliminable_regset; static int allocno_compare PROTO((const GENERIC_PTR, const GENERIC_PTR)); static void global_conflicts PROTO((void)); static void expand_preferences PROTO((void)); static void prune_preferences PROTO((void)); static void find_reg PROTO((int, HARD_REG_SET, int, int, int)); static void record_one_conflict PROTO((int)); static void record_conflicts PROTO((short *, int)); static void mark_reg_store PROTO((rtx, rtx)); static void mark_reg_clobber PROTO((rtx, rtx)); static void mark_reg_conflicts PROTO((rtx)); static void mark_reg_death PROTO((rtx)); static void mark_reg_live_nc PROTO((int, enum machine_mode)); static void set_preference PROTO((rtx, rtx)); static void dump_conflicts PROTO((FILE *)); /* Perform allocation of pseudo-registers not allocated by local_alloc. FILE is a file to output debugging information on, or zero if such output is not desired. Return value is nonzero if reload failed and we must not do any more for this function. */ int global_alloc (file) FILE *file; { int retval; #ifdef ELIMINABLE_REGS static struct {int from, to; } eliminables[] = ELIMINABLE_REGS; #endif int need_fp = (! flag_omit_frame_pointer #ifdef EXIT_IGNORE_STACK || (current_function_calls_alloca && EXIT_IGNORE_STACK) #endif || FRAME_POINTER_REQUIRED); register int i; rtx x; max_allocno = 0; /* A machine may have certain hard registers that are safe to use only within a basic block. */ CLEAR_HARD_REG_SET (no_global_alloc_regs); #ifdef OVERLAPPING_REGNO_P for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) if (OVERLAPPING_REGNO_P (i)) SET_HARD_REG_BIT (no_global_alloc_regs, i); #endif /* Build the regset of all eliminable registers and show we can't use those that we already know won't be eliminated. */ #ifdef ELIMINABLE_REGS for (i = 0; i < sizeof eliminables / sizeof eliminables[0]; i++) { SET_HARD_REG_BIT (eliminable_regset, eliminables[i].from); if (! CAN_ELIMINATE (eliminables[i].from, eliminables[i].to) || (eliminables[i].to == STACK_POINTER_REGNUM && need_fp)) SET_HARD_REG_BIT (no_global_alloc_regs, eliminables[i].from); } #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM SET_HARD_REG_BIT (eliminable_regset, HARD_FRAME_POINTER_REGNUM); if (need_fp) SET_HARD_REG_BIT (no_global_alloc_regs, HARD_FRAME_POINTER_REGNUM); #endif #else SET_HARD_REG_BIT (eliminable_regset, FRAME_POINTER_REGNUM); if (need_fp) SET_HARD_REG_BIT (no_global_alloc_regs, FRAME_POINTER_REGNUM); #endif /* Track which registers have already been used. Start with registers explicitly in the rtl, then registers allocated by local register allocation. */ CLEAR_HARD_REG_SET (regs_used_so_far); #ifdef LEAF_REGISTERS /* If we are doing the leaf function optimization, and this is a leaf function, it means that the registers that take work to save are those that need a register window. So prefer the ones that can be used in a leaf function. */ { char *cheap_regs; static char leaf_regs[] = LEAF_REGISTERS; if (only_leaf_regs_used () && leaf_function_p ()) cheap_regs = leaf_regs; else cheap_regs = call_used_regs; for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) if (regs_ever_live[i] || cheap_regs[i]) SET_HARD_REG_BIT (regs_used_so_far, i); } #else /* We consider registers that do not have to be saved over calls as if they were already used since there is no cost in using them. */ for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) if (regs_ever_live[i] || call_used_regs[i]) SET_HARD_REG_BIT (regs_used_so_far, i); #endif for (i = FIRST_PSEUDO_REGISTER; i < max_regno; i++) if (reg_renumber[i] >= 0) SET_HARD_REG_BIT (regs_used_so_far, reg_renumber[i]); /* Establish mappings from register number to allocation number and vice versa. In the process, count the allocnos. */ reg_allocno = (int *) alloca (max_regno * sizeof (int)); for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) reg_allocno[i] = -1; /* Initialize the shared-hard-reg mapping from the list of pairs that may share. */ reg_may_share = (int *) alloca (max_regno * sizeof (int)); bzero ((char *) reg_may_share, max_regno * sizeof (int)); for (x = regs_may_share; x; x = XEXP (XEXP (x, 1), 1)) { int r1 = REGNO (XEXP (x, 0)); int r2 = REGNO (XEXP (XEXP (x, 1), 0)); if (r1 > r2) reg_may_share[r1] = r2; else reg_may_share[r2] = r1; } for (i = FIRST_PSEUDO_REGISTER; i < max_regno; i++) /* Note that reg_live_length[i] < 0 indicates a "constant" reg that we are supposed to refrain from putting in a hard reg. -2 means do make an allocno but don't allocate it. */ if (REG_N_REFS (i) != 0 && reg_renumber[i] < 0 && REG_LIVE_LENGTH (i) != -1 /* Don't allocate pseudos that cross calls, if this function receives a nonlocal goto. */ && (! current_function_has_nonlocal_label || REG_N_CALLS_CROSSED (i) == 0)) { if (reg_may_share[i] && reg_allocno[reg_may_share[i]] >= 0) reg_allocno[i] = reg_allocno[reg_may_share[i]]; else reg_allocno[i] = max_allocno++; if (REG_LIVE_LENGTH (i) == 0) abort (); } else reg_allocno[i] = -1; allocno_reg = (int *) alloca (max_allocno * sizeof (int)); allocno_size = (int *) alloca (max_allocno * sizeof (int)); allocno_calls_crossed = (int *) alloca (max_allocno * sizeof (int)); allocno_n_refs = (int *) alloca (max_allocno * sizeof (int)); allocno_live_length = (int *) alloca (max_allocno * sizeof (int)); bzero ((char *) allocno_size, max_allocno * sizeof (int)); bzero ((char *) allocno_calls_crossed, max_allocno * sizeof (int)); bzero ((char *) allocno_n_refs, max_allocno * sizeof (int)); bzero ((char *) allocno_live_length, max_allocno * sizeof (int)); for (i = FIRST_PSEUDO_REGISTER; i < max_regno; i++) if (reg_allocno[i] >= 0) { int allocno = reg_allocno[i]; allocno_reg[allocno] = i; allocno_size[allocno] = PSEUDO_REGNO_SIZE (i); allocno_calls_crossed[allocno] += REG_N_CALLS_CROSSED (i); allocno_n_refs[allocno] += REG_N_REFS (i); if (allocno_live_length[allocno] < REG_LIVE_LENGTH (i)) allocno_live_length[allocno] = REG_LIVE_LENGTH (i); } /* Calculate amount of usage of each hard reg by pseudos allocated by local-alloc. This is to see if we want to override it. */ bzero ((char *) local_reg_live_length, sizeof local_reg_live_length); bzero ((char *) local_reg_n_refs, sizeof local_reg_n_refs); for (i = FIRST_PSEUDO_REGISTER; i < max_regno; i++) if (reg_allocno[i] < 0 && reg_renumber[i] >= 0) { int regno = reg_renumber[i]; int endregno = regno + HARD_REGNO_NREGS (regno, PSEUDO_REGNO_MODE (i)); int j; for (j = regno; j < endregno; j++) { local_reg_n_refs[j] += REG_N_REFS (i); local_reg_live_length[j] += REG_LIVE_LENGTH (i); } } /* We can't override local-alloc for a reg used not just by local-alloc. */ for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) if (regs_ever_live[i]) local_reg_n_refs[i] = 0; /* Likewise for regs used in a SCRATCH. */ for (i = 0; i < scratch_list_length; i++) if (scratch_list[i]) { int regno = REGNO (scratch_list[i]); int lim = regno + HARD_REGNO_NREGS (regno, GET_MODE (scratch_list[i])); int j; for (j = regno; j < lim; j++) local_reg_n_refs[j] = 0; } /* Allocate the space for the conflict and preference tables and initialize them. */ hard_reg_conflicts = (HARD_REG_SET *) alloca (max_allocno * sizeof (HARD_REG_SET)); bzero ((char *) hard_reg_conflicts, max_allocno * sizeof (HARD_REG_SET)); hard_reg_preferences = (HARD_REG_SET *) alloca (max_allocno * sizeof (HARD_REG_SET)); bzero ((char *) hard_reg_preferences, max_allocno * sizeof (HARD_REG_SET)); hard_reg_copy_preferences = (HARD_REG_SET *) alloca (max_allocno * sizeof (HARD_REG_SET)); bzero ((char *) hard_reg_copy_preferences, max_allocno * sizeof (HARD_REG_SET)); hard_reg_full_preferences = (HARD_REG_SET *) alloca (max_allocno * sizeof (HARD_REG_SET)); bzero ((char *) hard_reg_full_preferences, max_allocno * sizeof (HARD_REG_SET)); regs_someone_prefers = (HARD_REG_SET *) alloca (max_allocno * sizeof (HARD_REG_SET)); bzero ((char *) regs_someone_prefers, max_allocno * sizeof (HARD_REG_SET)); allocno_row_words = (max_allocno + INT_BITS - 1) / INT_BITS; /* We used to use alloca here, but the size of what it would try to allocate would occasionally cause it to exceed the stack limit and cause unpredictable core dumps. Some examples were > 2Mb in size. */ conflicts = (INT_TYPE *) xmalloc (max_allocno * allocno_row_words * sizeof (INT_TYPE)); bzero ((char *) conflicts, max_allocno * allocno_row_words * sizeof (INT_TYPE)); allocnos_live = (INT_TYPE *) alloca (allocno_row_words * sizeof (INT_TYPE)); /* If there is work to be done (at least one reg to allocate), perform global conflict analysis and allocate the regs. */ if (max_allocno > 0) { /* Scan all the insns and compute the conflicts among allocnos and between allocnos and hard regs. */ global_conflicts (); /* Eliminate conflicts between pseudos and eliminable registers. If the register is not eliminated, the pseudo won't really be able to live in the eliminable register, so the conflict doesn't matter. If we do eliminate the register, the conflict will no longer exist. So in either case, we can ignore the conflict. Likewise for preferences. */ for (i = 0; i < max_allocno; i++) { AND_COMPL_HARD_REG_SET (hard_reg_conflicts[i], eliminable_regset); AND_COMPL_HARD_REG_SET (hard_reg_copy_preferences[i], eliminable_regset); AND_COMPL_HARD_REG_SET (hard_reg_preferences[i], eliminable_regset); } /* Try to expand the preferences by merging them between allocnos. */ expand_preferences (); /* Determine the order to allocate the remaining pseudo registers. */ allocno_order = (int *) alloca (max_allocno * sizeof (int)); for (i = 0; i < max_allocno; i++) allocno_order[i] = i; /* Default the size to 1, since allocno_compare uses it to divide by. Also convert allocno_live_length of zero to -1. A length of zero can occur when all the registers for that allocno have reg_live_length equal to -2. In this case, we want to make an allocno, but not allocate it. So avoid the divide-by-zero and set it to a low priority. */ for (i = 0; i < max_allocno; i++) { if (allocno_size[i] == 0) allocno_size[i] = 1; if (allocno_live_length[i] == 0) allocno_live_length[i] = -1; } qsort (allocno_order, max_allocno, sizeof (int), allocno_compare); prune_preferences (); if (file) dump_conflicts (file); /* Try allocating them, one by one, in that order, except for parameters marked with reg_live_length[regno] == -2. */ for (i = 0; i < max_allocno; i++) if (REG_LIVE_LENGTH (allocno_reg[allocno_order[i]]) >= 0) { /* If we have more than one register class, first try allocating in the class that is cheapest for this pseudo-reg. If that fails, try any reg. */ if (N_REG_CLASSES > 1) { find_reg (allocno_order[i], HARD_CONST (0), 0, 0, 0); if (reg_renumber[allocno_reg[allocno_order[i]]] >= 0) continue; } if (reg_alternate_class (allocno_reg[allocno_order[i]]) != NO_REGS) find_reg (allocno_order[i], HARD_CONST (0), 1, 0, 0); } } /* Do the reloads now while the allocno data still exist, so that we can try to assign new hard regs to any pseudo regs that are spilled. */ #if 0 /* We need to eliminate regs even if there is no rtl code, for the sake of debugging information. */ if (n_basic_blocks > 0) #endif retval = reload (get_insns (), 1, file); free (conflicts); return retval; } /* Sort predicate for ordering the allocnos. Returns -1 (1) if *v1 should be allocated before (after) *v2. */ static int allocno_compare (v1p, v2p) const GENERIC_PTR v1p; const GENERIC_PTR v2p; { int v1 = *(int *)v1p, v2 = *(int *)v2p; /* Note that the quotient will never be bigger than the value of floor_log2 times the maximum number of times a register can occur in one insn (surely less than 100). Multiplying this by 10000 can't overflow. */ register int pri1 = (((double) (floor_log2 (allocno_n_refs[v1]) * allocno_n_refs[v1]) / allocno_live_length[v1]) * 10000 * allocno_size[v1]); register int pri2 = (((double) (floor_log2 (allocno_n_refs[v2]) * allocno_n_refs[v2]) / allocno_live_length[v2]) * 10000 * allocno_size[v2]); if (pri2 - pri1) return pri2 - pri1; /* If regs are equally good, sort by allocno, so that the results of qsort leave nothing to chance. */ return v1 - v2; } /* Scan the rtl code and record all conflicts and register preferences in the conflict matrices and preference tables. */ static void global_conflicts () { register int b, i; register rtx insn; short *block_start_allocnos; /* Make a vector that mark_reg_{store,clobber} will store in. */ regs_set = (rtx *) alloca (max_parallel * sizeof (rtx) * 2); block_start_allocnos = (short *) alloca (max_allocno * sizeof (short)); for (b = 0; b < n_basic_blocks; b++) { bzero ((char *) allocnos_live, allocno_row_words * sizeof (INT_TYPE)); /* Initialize table of registers currently live to the state at the beginning of this basic block. This also marks the conflicts among them. For pseudo-regs, there is only one bit for each one no matter how many hard regs it occupies. This is ok; we know the size from PSEUDO_REGNO_SIZE. For explicit hard regs, we cannot know the size that way since one hard reg can be used with various sizes. Therefore, we must require that all the hard regs implicitly live as part of a multi-word hard reg are explicitly marked in basic_block_live_at_start. */ { register regset old = basic_block_live_at_start[b]; int ax = 0; REG_SET_TO_HARD_REG_SET (hard_regs_live, old); EXECUTE_IF_SET_IN_REG_SET (old, FIRST_PSEUDO_REGISTER, i, { register int a = reg_allocno[i]; if (a >= 0) { SET_ALLOCNO_LIVE (a); block_start_allocnos[ax++] = a; } else if ((a = reg_renumber[i]) >= 0) mark_reg_live_nc (a, PSEUDO_REGNO_MODE (i)); }); /* Record that each allocno now live conflicts with each other allocno now live, and with each hard reg now live. */ record_conflicts (block_start_allocnos, ax); } insn = basic_block_head[b]; /* Scan the code of this basic block, noting which allocnos and hard regs are born or die. When one is born, record a conflict with all others currently live. */ while (1) { register RTX_CODE code = GET_CODE (insn); register rtx link; /* Make regs_set an empty set. */ n_regs_set = 0; if (code == INSN || code == CALL_INSN || code == JUMP_INSN) { #if 0 int i = 0; for (link = REG_NOTES (insn); link && i < NUM_NO_CONFLICT_PAIRS; link = XEXP (link, 1)) if (REG_NOTE_KIND (link) == REG_NO_CONFLICT) { no_conflict_pairs[i].allocno1 = reg_allocno[REGNO (SET_DEST (PATTERN (insn)))]; no_conflict_pairs[i].allocno2 = reg_allocno[REGNO (XEXP (link, 0))]; i++; } #endif /* 0 */ /* Mark any registers clobbered by INSN as live, so they conflict with the inputs. */ note_stores (PATTERN (insn), mark_reg_clobber); /* 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); #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); #endif /* If INSN has multiple outputs, then any reg that dies here and is used inside of an output must conflict with the other outputs. */ if (GET_CODE (PATTERN (insn)) == PARALLEL && !single_set (insn)) for (link = REG_NOTES (insn); link; link = XEXP (link, 1)) if (REG_NOTE_KIND (link) == REG_DEAD) { int used_in_output = 0; int i; rtx reg = XEXP (link, 0); for (i = XVECLEN (PATTERN (insn), 0) - 1; i >= 0; i--) { rtx set = XVECEXP (PATTERN (insn), 0, i); if (GET_CODE (set) == SET && GET_CODE (SET_DEST (set)) != REG && !rtx_equal_p (reg, SET_DEST (set)) && reg_overlap_mentioned_p (reg, SET_DEST (set))) used_in_output = 1; } if (used_in_output) mark_reg_conflicts (reg); } /* Mark any registers set in INSN and then never used. */ while (n_regs_set > 0) if (find_regno_note (insn, REG_UNUSED, REGNO (regs_set[--n_regs_set]))) mark_reg_death (regs_set[n_regs_set]); } if (insn == basic_block_end[b]) break; insn = NEXT_INSN (insn); } } } /* Expand the preference information by looking for cases where one allocno dies in an insn that sets an allocno. If those two allocnos don't conflict, merge any preferences between those allocnos. */ static void expand_preferences () { rtx insn; rtx link; rtx set; /* We only try to handle the most common cases here. Most of the cases where this wins are reg-reg copies. */ for (insn = get_insns (); insn; insn = NEXT_INSN (insn)) if (GET_RTX_CLASS (GET_CODE (insn)) == 'i' && (set = single_set (insn)) != 0 && GET_CODE (SET_DEST (set)) == REG && reg_allocno[REGNO (SET_DEST (set))] >= 0) for (link = REG_NOTES (insn); link; link = XEXP (link, 1)) if (REG_NOTE_KIND (link) == REG_DEAD && GET_CODE (XEXP (link, 0)) == REG && reg_allocno[REGNO (XEXP (link, 0))] >= 0 && ! CONFLICTP (reg_allocno[REGNO (SET_DEST (set))], reg_allocno[REGNO (XEXP (link, 0))]) && ! CONFLICTP (reg_allocno[REGNO (XEXP (link, 0))], reg_allocno[REGNO (SET_DEST (set))])) { int a1 = reg_allocno[REGNO (SET_DEST (set))]; int a2 = reg_allocno[REGNO (XEXP (link, 0))]; if (XEXP (link, 0) == SET_SRC (set)) { IOR_HARD_REG_SET (hard_reg_copy_preferences[a1], hard_reg_copy_preferences[a2]); IOR_HARD_REG_SET (hard_reg_copy_preferences[a2], hard_reg_copy_preferences[a1]); } IOR_HARD_REG_SET (hard_reg_preferences[a1], hard_reg_preferences[a2]); IOR_HARD_REG_SET (hard_reg_preferences[a2], hard_reg_preferences[a1]); IOR_HARD_REG_SET (hard_reg_full_preferences[a1], hard_reg_full_preferences[a2]); IOR_HARD_REG_SET (hard_reg_full_preferences[a2], hard_reg_full_preferences[a1]); } } /* Prune the preferences for global registers to exclude registers that cannot be used. Compute `regs_someone_prefers', which is a bitmask of the hard registers that are preferred by conflicting registers of lower priority. If possible, we will avoid using these registers. */ static void prune_preferences () { int i, j; int allocno; /* Scan least most important to most important. For each allocno, remove from preferences registers that cannot be used, either because of conflicts or register type. Then compute all registers preferred by each lower-priority register that conflicts. */ for (i = max_allocno - 1; i >= 0; i--) { HARD_REG_SET temp; allocno = allocno_order[i]; COPY_HARD_REG_SET (temp, hard_reg_conflicts[allocno]); if (allocno_calls_crossed[allocno] == 0) IOR_HARD_REG_SET (temp, fixed_reg_set); else IOR_HARD_REG_SET (temp, call_used_reg_set); IOR_COMPL_HARD_REG_SET (temp, reg_class_contents[(int) reg_preferred_class (allocno_reg[allocno])]); AND_COMPL_HARD_REG_SET (hard_reg_preferences[allocno], temp); AND_COMPL_HARD_REG_SET (hard_reg_copy_preferences[allocno], temp); AND_COMPL_HARD_REG_SET (hard_reg_full_preferences[allocno], temp); CLEAR_HARD_REG_SET (regs_someone_prefers[allocno]); /* Merge in the preferences of lower-priority registers (they have already been pruned). If we also prefer some of those registers, don't exclude them unless we are of a smaller size (in which case we want to give the lower-priority allocno the first chance for these registers). */ for (j = i + 1; j < max_allocno; j++) if (CONFLICTP (allocno, allocno_order[j]) || CONFLICTP (allocno_order[j], allocno)) { COPY_HARD_REG_SET (temp, hard_reg_full_preferences[allocno_order[j]]); if (allocno_size[allocno_order[j]] <= allocno_size[allocno]) AND_COMPL_HARD_REG_SET (temp, hard_reg_full_preferences[allocno]); IOR_HARD_REG_SET (regs_someone_prefers[allocno], temp); } } } /* Assign a hard register to ALLOCNO; look for one that is the beginning of a long enough stretch of hard regs none of which conflicts with ALLOCNO. The registers marked in PREFREGS are tried first. LOSERS, if non-zero, is a HARD_REG_SET indicating registers that cannot be used for this allocation. If ALT_REGS_P is zero, consider only the preferred class of ALLOCNO's reg. Otherwise ignore that preferred class and use the alternate class. If ACCEPT_CALL_CLOBBERED is nonzero, accept a call-clobbered hard reg that will have to be saved and restored at calls. RETRYING is nonzero if this is called from retry_global_alloc. If we find one, record it in reg_renumber. If not, do nothing. */ static void find_reg (allocno, losers, alt_regs_p, accept_call_clobbered, retrying) int allocno; HARD_REG_SET losers; int alt_regs_p; int accept_call_clobbered; int retrying; { register int i, best_reg, pass; #ifdef HARD_REG_SET register /* Declare it register if it's a scalar. */ #endif HARD_REG_SET used, used1, used2; enum reg_class class = (alt_regs_p ? reg_alternate_class (allocno_reg[allocno]) : reg_preferred_class (allocno_reg[allocno])); enum machine_mode mode = PSEUDO_REGNO_MODE (allocno_reg[allocno]); if (accept_call_clobbered) COPY_HARD_REG_SET (used1, call_fixed_reg_set); else if (allocno_calls_crossed[allocno] == 0) COPY_HARD_REG_SET (used1, fixed_reg_set); else COPY_HARD_REG_SET (used1, call_used_reg_set); /* Some registers should not be allocated in global-alloc. */ IOR_HARD_REG_SET (used1, no_global_alloc_regs); if (losers) IOR_HARD_REG_SET (used1, losers); IOR_COMPL_HARD_REG_SET (used1, reg_class_contents[(int) class]); COPY_HARD_REG_SET (used2, used1); IOR_HARD_REG_SET (used1, hard_reg_conflicts[allocno]); #ifdef CLASS_CANNOT_CHANGE_SIZE if (REG_CHANGES_SIZE (allocno_reg[allocno])) IOR_HARD_REG_SET (used1, reg_class_contents[(int) CLASS_CANNOT_CHANGE_SIZE]); #endif /* Try each hard reg to see if it fits. Do this in two passes. In the first pass, skip registers that are preferred by some other pseudo to give it a better chance of getting one of those registers. Only if we can't get a register when excluding those do we take one of them. However, we never allocate a register for the first time in pass 0. */ COPY_HARD_REG_SET (used, used1); IOR_COMPL_HARD_REG_SET (used, regs_used_so_far); IOR_HARD_REG_SET (used, regs_someone_prefers[allocno]); best_reg = -1; for (i = FIRST_PSEUDO_REGISTER, pass = 0; pass <= 1 && i >= FIRST_PSEUDO_REGISTER; pass++) { if (pass == 1) COPY_HARD_REG_SET (used, used1); for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) { #ifdef REG_ALLOC_ORDER int regno = reg_alloc_order[i]; #else int regno = i; #endif if (! TEST_HARD_REG_BIT (used, regno) && HARD_REGNO_MODE_OK (regno, mode)) { register int j; register int lim = regno + HARD_REGNO_NREGS (regno, mode); for (j = regno + 1; (j < lim && ! TEST_HARD_REG_BIT (used, j)); j++); if (j == lim) { best_reg = regno; break; } #ifndef REG_ALLOC_ORDER i = j; /* Skip starting points we know will lose */ #endif } } } /* See if there is a preferred register with the same class as the register we allocated above. Making this restriction prevents register preferencing from creating worse register allocation. Remove from the preferred registers and conflicting registers. Note that additional conflicts may have been added after `prune_preferences' was called. First do this for those register with copy preferences, then all preferred registers. */ AND_COMPL_HARD_REG_SET (hard_reg_copy_preferences[allocno], used); GO_IF_HARD_REG_SUBSET (hard_reg_copy_preferences[allocno], reg_class_contents[(int) NO_REGS], no_copy_prefs); if (best_reg >= 0) { for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) if (TEST_HARD_REG_BIT (hard_reg_copy_preferences[allocno], i) && HARD_REGNO_MODE_OK (i, mode) && (REGNO_REG_CLASS (i) == REGNO_REG_CLASS (best_reg) || reg_class_subset_p (REGNO_REG_CLASS (i), REGNO_REG_CLASS (best_reg)) || reg_class_subset_p (REGNO_REG_CLASS (best_reg), REGNO_REG_CLASS (i)))) { register int j; register int lim = i + HARD_REGNO_NREGS (i, mode); for (j = i + 1; (j < lim && ! TEST_HARD_REG_BIT (used, j) && (REGNO_REG_CLASS (j) == REGNO_REG_CLASS (best_reg + (j - i)) || reg_class_subset_p (REGNO_REG_CLASS (j), REGNO_REG_CLASS (best_reg + (j - i))) || reg_class_subset_p (REGNO_REG_CLASS (best_reg + (j - i)), REGNO_REG_CLASS (j)))); j++); if (j == lim) { best_reg = i; goto no_prefs; } } } no_copy_prefs: AND_COMPL_HARD_REG_SET (hard_reg_preferences[allocno], used); GO_IF_HARD_REG_SUBSET (hard_reg_preferences[allocno], reg_class_contents[(int) NO_REGS], no_prefs); if (best_reg >= 0) { for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) if (TEST_HARD_REG_BIT (hard_reg_preferences[allocno], i) && HARD_REGNO_MODE_OK (i, mode) && (REGNO_REG_CLASS (i) == REGNO_REG_CLASS (best_reg) || reg_class_subset_p (REGNO_REG_CLASS (i), REGNO_REG_CLASS (best_reg)) || reg_class_subset_p (REGNO_REG_CLASS (best_reg), REGNO_REG_CLASS (i)))) { register int j; register int lim = i + HARD_REGNO_NREGS (i, mode); for (j = i + 1; (j < lim && ! TEST_HARD_REG_BIT (used, j) && (REGNO_REG_CLASS (j) == REGNO_REG_CLASS (best_reg + (j - i)) || reg_class_subset_p (REGNO_REG_CLASS (j), REGNO_REG_CLASS (best_reg + (j - i))) || reg_class_subset_p (REGNO_REG_CLASS (best_reg + (j - i)), REGNO_REG_CLASS (j)))); j++); if (j == lim) { best_reg = i; break; } } } no_prefs: /* If we haven't succeeded yet, try with caller-saves. We need not check to see if the current function has nonlocal labels because we don't put any pseudos that are live over calls in registers in that case. */ if (flag_caller_saves && best_reg < 0) { /* Did not find a register. If it would be profitable to allocate a call-clobbered register and save and restore it around calls, do that. */ if (! accept_call_clobbered && allocno_calls_crossed[allocno] != 0 && CALLER_SAVE_PROFITABLE (allocno_n_refs[allocno], allocno_calls_crossed[allocno])) { HARD_REG_SET new_losers; if (! losers) CLEAR_HARD_REG_SET (new_losers); else COPY_HARD_REG_SET (new_losers, losers); IOR_HARD_REG_SET(new_losers, losing_caller_save_reg_set); find_reg (allocno, new_losers, alt_regs_p, 1, retrying); if (reg_renumber[allocno_reg[allocno]] >= 0) { caller_save_needed = 1; return; } } } /* If we haven't succeeded yet, see if some hard reg that conflicts with us was utilized poorly by local-alloc. If so, kick out the regs that were put there by local-alloc so we can use it instead. */ if (best_reg < 0 && !retrying /* Let's not bother with multi-reg allocnos. */ && allocno_size[allocno] == 1) { /* Count from the end, to find the least-used ones first. */ for (i = FIRST_PSEUDO_REGISTER - 1; i >= 0; i--) { #ifdef REG_ALLOC_ORDER int regno = reg_alloc_order[i]; #else int regno = i; #endif if (local_reg_n_refs[regno] != 0 /* Don't use a reg no good for this pseudo. */ && ! TEST_HARD_REG_BIT (used2, regno) && HARD_REGNO_MODE_OK (regno, mode) #ifdef CLASS_CANNOT_CHANGE_SIZE && ! (REG_CHANGES_SIZE (allocno_reg[allocno]) && (TEST_HARD_REG_BIT (reg_class_contents[(int) CLASS_CANNOT_CHANGE_SIZE], regno))) #endif ) { /* We explicitly evaluate the divide results into temporary variables so as to avoid excess precision problems that occur on a i386-unknown-sysv4.2 (unixware) host. */ double tmp1 = ((double) local_reg_n_refs[regno] / local_reg_live_length[regno]); double tmp2 = ((double) allocno_n_refs[allocno] / allocno_live_length[allocno]); if (tmp1 < tmp2) { /* Hard reg REGNO was used less in total by local regs than it would be used by this one allocno! */ int k; for (k = 0; k < max_regno; k++) if (reg_renumber[k] >= 0) { int r = reg_renumber[k]; int endregno = r + HARD_REGNO_NREGS (r, PSEUDO_REGNO_MODE (k)); if (regno >= r && regno < endregno) reg_renumber[k] = -1; } best_reg = regno; break; } } } } /* Did we find a register? */ if (best_reg >= 0) { register int lim, j; HARD_REG_SET this_reg; /* Yes. Record it as the hard register of this pseudo-reg. */ reg_renumber[allocno_reg[allocno]] = best_reg; /* Also of any pseudo-regs that share with it. */ if (reg_may_share[allocno_reg[allocno]]) for (j = FIRST_PSEUDO_REGISTER; j < max_regno; j++) if (reg_allocno[j] == allocno) reg_renumber[j] = best_reg; /* Make a set of the hard regs being allocated. */ CLEAR_HARD_REG_SET (this_reg); lim = best_reg + HARD_REGNO_NREGS (best_reg, mode); for (j = best_reg; j < lim; j++) { SET_HARD_REG_BIT (this_reg, j); SET_HARD_REG_BIT (regs_used_so_far, j); /* This is no longer a reg used just by local regs. */ local_reg_n_refs[j] = 0; } /* For each other pseudo-reg conflicting with this one, mark it as conflicting with the hard regs this one occupies. */ lim = allocno; for (j = 0; j < max_allocno; j++) if (CONFLICTP (lim, j) || CONFLICTP (j, lim)) { IOR_HARD_REG_SET (hard_reg_conflicts[j], this_reg); } } } /* Called from `reload' to look for a hard reg to put pseudo reg REGNO in. Perhaps it had previously seemed not worth a hard reg, or perhaps its old hard reg has been commandeered for reloads. FORBIDDEN_REGS indicates certain hard regs that may not be used, even if they do not appear to be allocated. If FORBIDDEN_REGS is zero, no regs are forbidden. */ void retry_global_alloc (regno, forbidden_regs) int regno; HARD_REG_SET forbidden_regs; { int allocno = reg_allocno[regno]; if (allocno >= 0) { /* If we have more than one register class, first try allocating in the class that is cheapest for this pseudo-reg. If that fails, try any reg. */ if (N_REG_CLASSES > 1) find_reg (allocno, forbidden_regs, 0, 0, 1); if (reg_renumber[regno] < 0 && reg_alternate_class (regno) != NO_REGS) find_reg (allocno, forbidden_regs, 1, 0, 1); /* If we found a register, modify the RTL for the register to show the hard register, and mark that register live. */ if (reg_renumber[regno] >= 0) { REGNO (regno_reg_rtx[regno]) = reg_renumber[regno]; mark_home_live (regno); } } } /* Record a conflict between register REGNO and everything currently live. REGNO must not be a pseudo reg that was allocated by local_alloc; such numbers must be translated through reg_renumber before calling here. */ static void record_one_conflict (regno) int regno; { register int j; if (regno < FIRST_PSEUDO_REGISTER) /* When a hard register becomes live, record conflicts with live pseudo regs. */ for (j = 0; j < max_allocno; j++) { if (ALLOCNO_LIVE_P (j)) SET_HARD_REG_BIT (hard_reg_conflicts[j], regno); } else /* When a pseudo-register becomes live, record conflicts first with hard regs, then with other pseudo regs. */ { register int ialloc = reg_allocno[regno]; register int ialloc_prod = ialloc * allocno_row_words; IOR_HARD_REG_SET (hard_reg_conflicts[ialloc], hard_regs_live); for (j = allocno_row_words - 1; j >= 0; j--) { #if 0 int k; for (k = 0; k < n_no_conflict_pairs; k++) if (! ((j == no_conflict_pairs[k].allocno1 && ialloc == no_conflict_pairs[k].allocno2) || (j == no_conflict_pairs[k].allocno2 && ialloc == no_conflict_pairs[k].allocno1))) #endif /* 0 */ conflicts[ialloc_prod + j] |= allocnos_live[j]; } } } /* Record all allocnos currently live as conflicting with each other and with all hard regs currently live. ALLOCNO_VEC is a vector of LEN allocnos, all allocnos that are currently live. Their bits are also flagged in allocnos_live. */ static void record_conflicts (allocno_vec, len) register short *allocno_vec; register int len; { register int allocno; register int j; register int ialloc_prod; while (--len >= 0) { allocno = allocno_vec[len]; ialloc_prod = allocno * allocno_row_words; IOR_HARD_REG_SET (hard_reg_conflicts[allocno], hard_regs_live); for (j = allocno_row_words - 1; j >= 0; j--) conflicts[ialloc_prod + j] |= allocnos_live[j]; } } /* Handle the case where REG is set by the insn being scanned, during the forward scan to accumulate conflicts. Store a 1 in regs_live or allocnos_live for this register, record how many consecutive hardware registers it actually needs, and record a conflict with all other registers already live. Note that even if REG does not remain alive after this insn, we must mark it here as live, to ensure a conflict between REG and any other regs set in this insn that really do live. This is because those other regs could be considered after this. REG might actually be something other than a register; if so, we do nothing. SETTER is 0 if this register was modified by an auto-increment (i.e., a REG_INC note was found for it). CLOBBERs are processed here by calling mark_reg_clobber. */ static void mark_reg_store (orig_reg, setter) rtx orig_reg, setter; { register int regno; register rtx reg = orig_reg; /* WORD is which word of a multi-register group is being stored. For the case where the store is actually into a SUBREG of REG. Except we don't use it; I believe the entire REG needs to be made live. */ int word = 0; if (GET_CODE (reg) == SUBREG) { word = SUBREG_WORD (reg); reg = SUBREG_REG (reg); } if (GET_CODE (reg) != REG) return; if (setter && GET_CODE (setter) == CLOBBER) { /* A clobber of a register should be processed here too. */ mark_reg_clobber (orig_reg, setter); return; } regs_set[n_regs_set++] = reg; if (setter) set_preference (reg, SET_SRC (setter)); regno = REGNO (reg); if (reg_renumber[regno] >= 0) regno = reg_renumber[regno] /* + word */; /* Either this is one of the max_allocno pseudo regs not allocated, or it is or has a hardware reg. First handle the pseudo-regs. */ if (regno >= FIRST_PSEUDO_REGISTER) { if (reg_allocno[regno] >= 0) { SET_ALLOCNO_LIVE (reg_allocno[regno]); record_one_conflict (regno); } } /* Handle hardware regs (and pseudos allocated to hard regs). */ else if (! fixed_regs[regno]) { register int last = regno + HARD_REGNO_NREGS (regno, GET_MODE (reg)); while (regno < last) { record_one_conflict (regno); SET_HARD_REG_BIT (hard_regs_live, regno); regno++; } } } /* Like mark_reg_set except notice just CLOBBERs; ignore SETs. */ static void mark_reg_clobber (reg, setter) rtx reg, setter; { register int regno; /* WORD is which word of a multi-register group is being stored. For the case where the store is actually into a SUBREG of REG. Except we don't use it; I believe the entire REG needs to be made live. */ int word = 0; if (GET_CODE (setter) != CLOBBER) return; if (GET_CODE (reg) == SUBREG) { word = SUBREG_WORD (reg); reg = SUBREG_REG (reg); } if (GET_CODE (reg) != REG) return; regs_set[n_regs_set++] = reg; regno = REGNO (reg); if (reg_renumber[regno] >= 0) regno = reg_renumber[regno] /* + word */; /* Either this is one of the max_allocno pseudo regs not allocated, or it is or has a hardware reg. First handle the pseudo-regs. */ if (regno >= FIRST_PSEUDO_REGISTER) { if (reg_allocno[regno] >= 0) { SET_ALLOCNO_LIVE (reg_allocno[regno]); record_one_conflict (regno); } } /* Handle hardware regs (and pseudos allocated to hard regs). */ else if (! fixed_regs[regno]) { register int last = regno + HARD_REGNO_NREGS (regno, GET_MODE (reg)); while (regno < last) { record_one_conflict (regno); SET_HARD_REG_BIT (hard_regs_live, regno); regno++; } } } /* Record that REG has conflicts with all the regs currently live. Do not mark REG itself as live. */ static void mark_reg_conflicts (reg) rtx reg; { register int regno; if (GET_CODE (reg) == SUBREG) reg = SUBREG_REG (reg); if (GET_CODE (reg) != REG) return; regno = REGNO (reg); if (reg_renumber[regno] >= 0) regno = reg_renumber[regno]; /* Either this is one of the max_allocno pseudo regs not allocated, or it is or has a hardware reg. First handle the pseudo-regs. */ if (regno >= FIRST_PSEUDO_REGISTER) { if (reg_allocno[regno] >= 0) record_one_conflict (regno); } /* Handle hardware regs (and pseudos allocated to hard regs). */ else if (! fixed_regs[regno]) { register int last = regno + HARD_REGNO_NREGS (regno, GET_MODE (reg)); while (regno < last) { record_one_conflict (regno); regno++; } } } /* Mark REG as being dead (following the insn being scanned now). Store a 0 in regs_live or allocnos_live for this register. */ static void mark_reg_death (reg) rtx reg; { register int regno = REGNO (reg); /* For pseudo reg, see if it has been assigned a hardware reg. */ if (reg_renumber[regno] >= 0) regno = reg_renumber[regno]; /* Either this is one of the max_allocno pseudo regs not allocated, or it is a hardware reg. First handle the pseudo-regs. */ if (regno >= FIRST_PSEUDO_REGISTER) { if (reg_allocno[regno] >= 0) CLEAR_ALLOCNO_LIVE (reg_allocno[regno]); } /* Handle hardware regs (and pseudos allocated to hard regs). */ else if (! fixed_regs[regno]) { /* Pseudo regs already assigned hardware regs are treated almost the same as explicit hardware regs. */ register int last = regno + HARD_REGNO_NREGS (regno, GET_MODE (reg)); while (regno < last) { CLEAR_HARD_REG_BIT (hard_regs_live, regno); regno++; } } } /* Mark hard reg REGNO as currently live, assuming machine mode MODE for the value stored in it. MODE determines how many consecutive registers are actually in use. Do not record conflicts; it is assumed that the caller will do that. */ static void mark_reg_live_nc (regno, mode) register int regno; enum machine_mode mode; { register int last = regno + HARD_REGNO_NREGS (regno, mode); while (regno < last) { SET_HARD_REG_BIT (hard_regs_live, regno); regno++; } } /* Try to set a preference for an allocno to a hard register. We are passed DEST and SRC which are the operands of a SET. It is known that SRC is a register. If SRC or the first operand of SRC is a register, try to set a preference. If one of the two is a hard register and the other is a pseudo-register, mark the preference. Note that we are not as aggressive as local-alloc in trying to tie a pseudo-register to a hard register. */ static void set_preference (dest, src) rtx dest, src; { int src_regno, dest_regno; /* Amount to add to the hard regno for SRC, or subtract from that for DEST, to compensate for subregs in SRC or DEST. */ int offset = 0; int i; int copy = 1; if (GET_RTX_FORMAT (GET_CODE (src))[0] == 'e') src = XEXP (src, 0), copy = 0; /* Get the reg number for both SRC and DEST. If neither is a reg, give up. */ if (GET_CODE (src) == REG) src_regno = REGNO (src); else if (GET_CODE (src) == SUBREG && GET_CODE (SUBREG_REG (src)) == REG) { src_regno = REGNO (SUBREG_REG (src)); offset += SUBREG_WORD (src); } else return; if (GET_CODE (dest) == REG) dest_regno = REGNO (dest); else if (GET_CODE (dest) == SUBREG && GET_CODE (SUBREG_REG (dest)) == REG) { dest_regno = REGNO (SUBREG_REG (dest)); offset -= SUBREG_WORD (dest); } else return; /* Convert either or both to hard reg numbers. */ if (reg_renumber[src_regno] >= 0) src_regno = reg_renumber[src_regno]; if (reg_renumber[dest_regno] >= 0) dest_regno = reg_renumber[dest_regno]; /* Now if one is a hard reg and the other is a global pseudo then give the other a preference. */ if (dest_regno < FIRST_PSEUDO_REGISTER && src_regno >= FIRST_PSEUDO_REGISTER && reg_allocno[src_regno] >= 0) { dest_regno -= offset; if (dest_regno >= 0 && dest_regno < FIRST_PSEUDO_REGISTER) { if (copy) SET_REGBIT (hard_reg_copy_preferences, reg_allocno[src_regno], dest_regno); SET_REGBIT (hard_reg_preferences, reg_allocno[src_regno], dest_regno); for (i = dest_regno; i < dest_regno + HARD_REGNO_NREGS (dest_regno, GET_MODE (dest)); i++) SET_REGBIT (hard_reg_full_preferences, reg_allocno[src_regno], i); } } if (src_regno < FIRST_PSEUDO_REGISTER && dest_regno >= FIRST_PSEUDO_REGISTER && reg_allocno[dest_regno] >= 0) { src_regno += offset; if (src_regno >= 0 && src_regno < FIRST_PSEUDO_REGISTER) { if (copy) SET_REGBIT (hard_reg_copy_preferences, reg_allocno[dest_regno], src_regno); SET_REGBIT (hard_reg_preferences, reg_allocno[dest_regno], src_regno); for (i = src_regno; i < src_regno + HARD_REGNO_NREGS (src_regno, GET_MODE (src)); i++) SET_REGBIT (hard_reg_full_preferences, reg_allocno[dest_regno], i); } } } /* Indicate that hard register number FROM was eliminated and replaced with an offset from hard register number TO. The status of hard registers live at the start of a basic block is updated by replacing a use of FROM with a use of TO. */ void mark_elimination (from, to) int from, to; { int i; for (i = 0; i < n_basic_blocks; i++) if (REGNO_REG_SET_P (basic_block_live_at_start[i], from)) { CLEAR_REGNO_REG_SET (basic_block_live_at_start[i], from); SET_REGNO_REG_SET (basic_block_live_at_start[i], to); } } /* Print debugging trace information if -greg switch is given, showing the information on which the allocation decisions are based. */ static void dump_conflicts (file) FILE *file; { register int i; register int has_preferences; fprintf (file, ";; %d regs to allocate:", max_allocno); for (i = 0; i < max_allocno; i++) { int j; fprintf (file, " %d", allocno_reg[allocno_order[i]]); for (j = 0; j < max_regno; j++) if (reg_allocno[j] == allocno_order[i] && j != allocno_reg[allocno_order[i]]) fprintf (file, "+%d", j); if (allocno_size[allocno_order[i]] != 1) fprintf (file, " (%d)", allocno_size[allocno_order[i]]); } fprintf (file, "\n"); for (i = 0; i < max_allocno; i++) { register int j; fprintf (file, ";; %d conflicts:", allocno_reg[i]); for (j = 0; j < max_allocno; j++) if (CONFLICTP (i, j) || CONFLICTP (j, i)) fprintf (file, " %d", allocno_reg[j]); for (j = 0; j < FIRST_PSEUDO_REGISTER; j++) if (TEST_HARD_REG_BIT (hard_reg_conflicts[i], j)) fprintf (file, " %d", j); fprintf (file, "\n"); has_preferences = 0; for (j = 0; j < FIRST_PSEUDO_REGISTER; j++) if (TEST_HARD_REG_BIT (hard_reg_preferences[i], j)) has_preferences = 1; if (! has_preferences) continue; fprintf (file, ";; %d preferences:", allocno_reg[i]); for (j = 0; j < FIRST_PSEUDO_REGISTER; j++) if (TEST_HARD_REG_BIT (hard_reg_preferences[i], j)) fprintf (file, " %d", j); fprintf (file, "\n"); } fprintf (file, "\n"); } void dump_global_regs (file) FILE *file; { register int i, j; fprintf (file, ";; Register dispositions:\n"); for (i = FIRST_PSEUDO_REGISTER, j = 0; i < max_regno; i++) if (reg_renumber[i] >= 0) { fprintf (file, "%d in %d ", i, reg_renumber[i]); if (++j % 6 == 0) fprintf (file, "\n"); } fprintf (file, "\n\n;; Hard regs used: "); for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) if (regs_ever_live[i]) fprintf (file, " %d", i); fprintf (file, "\n\n"); }