/* Dummy data flow analysis for GNU compiler in nonoptimizing mode.
- Copyright (C) 1987, 1991, 1994 Free Software Foundation, Inc.
+ Copyright (C) 1987, 91, 94, 95, 96, 1997 Free Software Foundation, Inc.
This file is part of GNU CC.
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, 675 Mass Ave, Cambridge, MA 02139, USA. */
+the Free Software Foundation, 59 Temple Place - Suite 330,
+Boston, MA 02111-1307, USA. */
/* This file performs stupid register allocation, which is used
when cc1 gets the -noreg switch (which is when cc does not get -O).
- Stupid register allocation goes in place of the the flow_analysis,
+ Stupid register allocation goes in place of the flow_analysis,
local_alloc and global_alloc passes. combine_instructions cannot
be done with stupid allocation because the data flow info that it needs
is not computed here.
pseudo reg is computed. Then the pseudo regs are ordered by priority
and assigned hard regs in priority order. */
-#include <stdio.h>
#include "config.h"
+#include "system.h"
+
#include "rtl.h"
#include "hard-reg-set.h"
#include "regs.h"
static int last_call_suid;
+/* Record the suid of the last NOTE_INSN_SETJMP
+ so we can tell whether a pseudo reg crosses any setjmp. */
+
+static int last_setjmp_suid;
+
/* Element N is suid of insn where life span of pseudo reg N ends.
Element is 0 if register N has not been seen yet on backward scan. */
static char *regs_change_size;
+/* Indexed by reg number, nonzero if reg crosses a setjmp. */
+
+static char *regs_crosses_setjmp;
+
/* Indexed by insn's suid, the set of hard regs live after that insn. */
static HARD_REG_SET *after_insn_hard_regs;
#define MARK_LIVE_AFTER(INSN,REGNO) \
SET_HARD_REG_BIT (after_insn_hard_regs[INSN_SUID (INSN)], (REGNO))
-static int stupid_reg_compare PROTO((int *, int *));
+static int stupid_reg_compare PROTO((const GENERIC_PTR,const GENERIC_PTR));
static int stupid_find_reg PROTO((int, enum reg_class, enum machine_mode,
int, int, int));
static void stupid_mark_refs PROTO((rtx, rtx));
register rtx last, insn;
int max_uid, max_suid;
+ current_function_has_computed_jump = 0;
+
bzero (regs_ever_live, sizeof regs_ever_live);
regs_live = (char *) alloca (nregs);
}
last_call_suid = i + 1;
+ last_setjmp_suid = i + 1;
max_suid = i + 1;
max_regno = nregs;
regs_change_size = (char *) alloca (nregs * sizeof (char));
bzero ((char *) regs_change_size, nregs * sizeof (char));
- reg_renumber = (short *) oballoc (nregs * sizeof (short));
+ regs_crosses_setjmp = (char *) alloca (nregs * sizeof (char));
+ bzero ((char *) regs_crosses_setjmp, nregs * sizeof (char));
+
+ /* Allocate the reg_renumber array */
+ allocate_reg_info (max_regno, FALSE, TRUE);
for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
reg_renumber[i] = i;
- for (i = FIRST_VIRTUAL_REGISTER; i < max_regno; i++)
- reg_renumber[i] = -1;
-
after_insn_hard_regs
= (HARD_REG_SET *) alloca (max_suid * sizeof (HARD_REG_SET));
allocate_for_life_analysis ();
for (i = 0; i < max_regno; i++)
- reg_n_deaths[i] = 1;
+ REG_N_DEATHS (i) = 1;
bzero (regs_live, nregs);
if (GET_RTX_CLASS (GET_CODE (insn)) == 'i')
stupid_mark_refs (PATTERN (insn), insn);
- /* Mark all call-clobbered regs as live after each call insn
- so that a pseudo whose life span includes this insn
- will not go in one of them.
+ if (GET_CODE (insn) == NOTE
+ && NOTE_LINE_NUMBER (insn) == NOTE_INSN_SETJMP)
+ last_setjmp_suid = INSN_SUID (insn);
+
+ /* Mark all call-clobbered regs as dead after each call insn so that
+ a pseudo whose life span includes this insn will not go in one of
+ them. If the function contains a non-local goto, mark all hard
+ registers dead (except for stack related bits).
+
Then mark those regs as all dead for the continuing scan
of the insns before the call. */
if (GET_CODE (insn) == CALL_INSN)
{
last_call_suid = INSN_SUID (insn);
- IOR_HARD_REG_SET (after_insn_hard_regs[last_call_suid],
- call_used_reg_set);
- for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
- if (call_used_regs[i])
- regs_live[i] = 0;
+ if (current_function_has_nonlocal_label)
+ {
+ IOR_COMPL_HARD_REG_SET (after_insn_hard_regs[last_call_suid],
+ fixed_reg_set);
+ for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
+ if (! fixed_regs[i])
+ regs_live[i] = 0;
+ }
+ else
+ {
+ IOR_HARD_REG_SET (after_insn_hard_regs[last_call_suid],
+ call_used_reg_set);
+ for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
+ if (call_used_regs[i])
+ regs_live[i] = 0;
+ }
/* It is important that this be done after processing the insn's
pattern because we want the function result register to still
be live if it's also used to pass arguments. */
stupid_mark_refs (CALL_INSN_FUNCTION_USAGE (insn), insn);
}
+ if (GET_CODE (insn) == JUMP_INSN && computed_jump_p (insn))
+ current_function_has_computed_jump = 1;
}
/* Now decide the order in which to allocate the pseudo registers. */
{
register int r = reg_order[i];
- /* Some regnos disappear from the rtl. Ignore them to avoid crash. */
- if (regno_reg_rtx[r] == 0)
+ /* Some regnos disappear from the rtl. Ignore them to avoid crash.
+ Also don't allocate registers that cross a setjmp, or live across
+ a call if this function receives a nonlocal goto. */
+ if (regno_reg_rtx[r] == 0 || regs_crosses_setjmp[r]
+ || (REG_N_CALLS_CROSSED (r) > 0
+ && current_function_has_nonlocal_label))
continue;
/* Now find the best hard-register class for this pseudo register */
if (N_REG_CLASSES > 1)
- reg_renumber[r] = stupid_find_reg (reg_n_calls_crossed[r],
+ reg_renumber[r] = stupid_find_reg (REG_N_CALLS_CROSSED (r),
reg_preferred_class (r),
PSEUDO_REGNO_MODE (r),
reg_where_born[r],
/* If no reg available in that class, try alternate class. */
if (reg_renumber[r] == -1 && reg_alternate_class (r) != NO_REGS)
- reg_renumber[r] = stupid_find_reg (reg_n_calls_crossed[r],
+ reg_renumber[r] = stupid_find_reg (REG_N_CALLS_CROSSED (r),
reg_alternate_class (r),
PSEUDO_REGNO_MODE (r),
reg_where_born[r],
static int
stupid_reg_compare (r1p, r2p)
- int *r1p, *r2p;
+ const GENERIC_PTR r1p;
+ const GENERIC_PTR r2p;
{
- register int r1 = *r1p, r2 = *r2p;
+ register int r1 = *(int *)r1p, r2 = *(int *)r2p;
register int len1 = reg_where_dead[r1] - reg_where_born[r1];
register int len2 = reg_where_dead[r2] - reg_where_born[r2];
int tem;
if (tem != 0)
return tem;
- tem = reg_n_refs[r1] - reg_n_refs[r2];
+ tem = REG_N_REFS (r1) - REG_N_REFS (r2);
if (tem != 0)
return tem;
/* Find a block of SIZE words of hard registers in reg_class CLASS
that can hold a value of machine-mode MODE
(but actually we test only the first of the block for holding MODE)
- currently free from after insn whose suid is BIRTH
- through the insn whose suid is DEATH,
+ currently free from after insn whose suid is BORN_INSN
+ through the insn whose suid is DEAD_INSN,
and return the number of the first of them.
Return -1 if such a block cannot be found.
static struct {int from, to; } eliminables[] = ELIMINABLE_REGS;
#endif
+ /* If this register's life is more than 5,000 insns, we probably
+ can't allocate it, so don't waste the time trying. This avoids
+ quadratic behavior on programs that have regularly-occurring
+ SAVE_EXPRs. */
+ if (dead_insn > born_insn + 5000)
+ return -1;
+
COPY_HARD_REG_SET (used,
call_preserved ? call_used_reg_set : fixed_reg_set);
for (ins = born_insn; ins < dead_insn; ins++)
IOR_HARD_REG_SET (used, after_insn_hard_regs[ins]);
+#ifdef STACK_REGS
+ if (current_function_has_computed_jump)
+ for (i = FIRST_STACK_REG; i <= LAST_STACK_REG; i++)
+ SET_HARD_REG_BIT (used, i);
+#endif
+
IOR_COMPL_HARD_REG_SET (used, reg_class_contents[(int) class]);
#ifdef CLASS_CANNOT_CHANGE_SIZE
if (code == SET || code == CLOBBER)
{
- if (SET_DEST (x) != 0 && GET_CODE (SET_DEST (x)) == REG)
+ if (SET_DEST (x) != 0
+ && (GET_CODE (SET_DEST (x)) == REG
+ || (GET_CODE (SET_DEST (x)) == SUBREG
+ && GET_CODE (SUBREG_REG (SET_DEST (x))) == REG
+ && (REGNO (SUBREG_REG (SET_DEST (x)))
+ >= FIRST_PSEUDO_REGISTER))))
{
/* Register is being assigned. */
- regno = REGNO (SET_DEST (x));
+ /* If setting a SUBREG, we treat the entire reg as being set. */
+ if (GET_CODE (SET_DEST (x)) == SUBREG)
+ regno = REGNO (SUBREG_REG (SET_DEST (x)));
+ else
+ regno = REGNO (SET_DEST (x));
/* For hard regs, update the where-live info. */
if (regno < FIRST_PSEUDO_REGISTER)
/* The following line is for unused outputs;
they do get stored even though never used again. */
- MARK_LIVE_AFTER (insn, regno);
+ MARK_LIVE_AFTER (insn, regno+j);
/* When a hard reg is clobbered, mark it in use
just before this insn, so it is live all through. */
if (code == CLOBBER && INSN_SUID (insn) > 0)
SET_HARD_REG_BIT (after_insn_hard_regs[INSN_SUID (insn) - 1],
- regno);
+ regno+j);
}
}
/* For pseudo regs, record where born, where dead, number of
}
/* Count the refs of this reg. */
- reg_n_refs[regno]++;
+ REG_N_REFS (regno)++;
if (last_call_suid < reg_where_dead[regno])
- reg_n_calls_crossed[regno] += 1;
+ REG_N_CALLS_CROSSED (regno) += 1;
+
+ if (last_setjmp_suid < reg_where_dead[regno])
+ regs_crosses_setjmp[regno] = 1;
+
+ /* If this register is only used in this insn and is only
+ set, mark it unused. We have to do this even when not
+ optimizing so that MD patterns which count on this
+ behavior (e.g., it not causing an output reload on
+ an insn setting CC) will operate correctly. */
+ if (GET_CODE (SET_DEST (x)) == REG
+ && REGNO_FIRST_UID (regno) == INSN_UID (insn)
+ && REGNO_LAST_UID (regno) == INSN_UID (insn)
+ && (code == CLOBBER || ! reg_mentioned_p (SET_DEST (x),
+ SET_SRC (x))))
+ REG_NOTES (insn) = gen_rtx_EXPR_LIST (REG_UNUSED,
+ SET_DEST (x),
+ REG_NOTES (insn));
}
}
/* Pseudo reg: record first use, last use and number of uses. */
reg_where_born[regno] = INSN_SUID (insn);
- reg_n_refs[regno]++;
+ REG_N_REFS (regno)++;
if (regs_live[regno] == 0)
{
regs_live[regno] = 1;
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