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Commit 1e5bd841 by Bernd Schmidt Committed by Jeff Law
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reload1.c (reload): Break out several subroutines and make some variables global. 

	* reload1.c (reload): Break out several subroutines and make some
	variables global.
	(calculate_needs_all_insns): New function, broken out of reload.
	(calculate_needs): Likewise.
	(find_reload_regs): Likewise.
	(find_group): Likewise.
	(find_tworeg_group): Likewise.
	(something_needs_reloads): New global variable, formerly in reload.
	(something_needs_elimination): Likewise.
	(caller_save_spill_class): Likewise.
	(caller_save_group_size): Likewise.
	(max_needs): Likewise.
	(group_size): Likewise.
	(max_groups): Likewise.
	(max_nongroups): Likewise.
	(group_mode): Likewise.
	(max_needs_insn): Likewise.
	(max_groups_insn): Likewise.
	(max_nongroups_insn): Likewise.
	(failure): Likewise.

From-SVN: r22367
parent 5a0a1a66
Showing with 938 additions and 851 deletions
gcc/ChangeLog
Wed Sep 9 21:58:41 1998 Bernd Schmidt <crux@pool.informatik.rwth-aachen.de> Wed Sep 9 21:58:41 1998 Bernd Schmidt <crux@pool.informatik.rwth-aachen.de>
* reload1.c (reload): Break out several subroutines and make some
variables global.
(calculate_needs_all_insns): New function, broken out of reload.
(calculate_needs): Likewise.
(find_reload_regs): Likewise.
(find_group): Likewise.
(find_tworeg_group): Likewise.
(something_needs_reloads): New global variable, formerly in reload.
(something_needs_elimination): Likewise.
(caller_save_spill_class): Likewise.
(caller_save_group_size): Likewise.
(max_needs): Likewise.
(group_size): Likewise.
(max_groups): Likewise.
(max_nongroups): Likewise.
(group_mode): Likewise.
(max_needs_insn): Likewise.
(max_groups_insn): Likewise.
(max_nongroups_insn): Likewise.
(failure): Likewise.
* print-rtl.c (print_rtx): For MEMs, print MEM_ALIAS_SET. * print-rtl.c (print_rtx): For MEMs, print MEM_ALIAS_SET.
Wed Sep 9 13:14:41 1998 Richard Henderson <rth@cygnus.com> Wed Sep 9 13:14:41 1998 Richard Henderson <rth@cygnus.com>
......
gcc/reload1.c
...@@ -351,6 +351,11 @@ static int num_labels; ...@@ -351,6 +351,11 @@ static int num_labels;
struct hard_reg_n_uses { int regno; int uses; }; struct hard_reg_n_uses { int regno; int uses; };
static int calculate_needs_all_insns PROTO((rtx, int));
static int calculate_needs PROTO((int, rtx, rtx, int));
static int find_reload_regs PROTO((int, FILE *));
static int find_tworeg_group PROTO((int, int, FILE *));
static int find_group PROTO((int, int, FILE *));
static int possible_group_p PROTO((int, int *)); static int possible_group_p PROTO((int, int *));
static void count_possible_groups PROTO((int *, enum machine_mode *, static void count_possible_groups PROTO((int *, enum machine_mode *,
int *, int)); int *, int));
...@@ -511,6 +516,49 @@ init_reload () ...@@ -511,6 +516,49 @@ init_reload ()
} }
} }
/* Global variables used by reload and its subroutines. */
/* Set during calculate_needs if an insn needs reloading. */
static int something_needs_reloads;
/* Set during calculate_needs if an insn needs register elimination. */
static int something_needs_elimination;
/* Indicate whether caller saves need a spill register. */
static enum reg_class caller_save_spill_class = NO_REGS;
static int caller_save_group_size = 1;
/* For each class, number of reload regs needed in that class.
This is the maximum over all insns of the needs in that class
of the individual insn. */
static int max_needs[N_REG_CLASSES];
/* For each class, size of group of consecutive regs
that is needed for the reloads of this class. */
static int group_size[N_REG_CLASSES];
/* For each class, max number of consecutive groups needed.
(Each group contains group_size[CLASS] consecutive registers.) */
static int max_groups[N_REG_CLASSES];
/* For each class, max number needed of regs that don't belong
to any of the groups. */
static int max_nongroups[N_REG_CLASSES];
/* For each class, the machine mode which requires consecutive
groups of regs of that class.
If two different modes ever require groups of one class,
they must be the same size and equally restrictive for that class,
otherwise we can't handle the complexity. */
static enum machine_mode group_mode[N_REG_CLASSES];
/* Record the insn where each maximum need is first found. */
static rtx max_needs_insn[N_REG_CLASSES];
static rtx max_groups_insn[N_REG_CLASSES];
static rtx max_nongroups_insn[N_REG_CLASSES];
/* Nonzero means we couldn't get enough spill regs. */
static int failure;
/* Main entry point for the reload pass. /* Main entry point for the reload pass.
FIRST is the first insn of the function being compiled. FIRST is the first insn of the function being compiled.
...@@ -535,8 +583,7 @@ reload (first, global, dumpfile) ...@@ -535,8 +583,7 @@ reload (first, global, dumpfile)
int global; int global;
FILE *dumpfile; FILE *dumpfile;
{ {
register int class; register int i, j;
register int i, j, k;
register rtx insn; register rtx insn;
register struct elim_table *ep; register struct elim_table *ep;
...@@ -546,24 +593,18 @@ reload (first, global, dumpfile) ...@@ -546,24 +593,18 @@ reload (first, global, dumpfile)
int (*real_at_ptr)[NUM_ELIMINABLE_REGS]; int (*real_at_ptr)[NUM_ELIMINABLE_REGS];
int something_changed; int something_changed;
int something_needs_reloads;
int something_needs_elimination;
int new_basic_block_needs;
enum reg_class caller_save_spill_class = NO_REGS;
int caller_save_group_size = 1;
/* Nonzero means we couldn't get enough spill regs. */
int failure = 0;
/* The basic block number currently being processed for INSN. */
int this_block;
/* Make sure even insns with volatile mem refs are recognizable. */ /* Make sure even insns with volatile mem refs are recognizable. */
init_recog (); init_recog ();
failure = 0;
/* Enable find_equiv_reg to distinguish insns made by reload. */ /* Enable find_equiv_reg to distinguish insns made by reload. */
reload_first_uid = get_max_uid (); reload_first_uid = get_max_uid ();
caller_save_spill_class = NO_REGS;
caller_save_group_size = 1;
for (i = 0; i < N_REG_CLASSES; i++) for (i = 0; i < N_REG_CLASSES; i++)
basic_block_needs[i] = 0; basic_block_needs[i] = 0;
...@@ -864,31 +905,6 @@ reload (first, global, dumpfile) ...@@ -864,31 +905,6 @@ reload (first, global, dumpfile)
something_needs_elimination = 0; something_needs_elimination = 0;
while (something_changed) while (something_changed)
{ {
rtx after_call = 0;
/* For each class, number of reload regs needed in that class.
This is the maximum over all insns of the needs in that class
of the individual insn. */
int max_needs[N_REG_CLASSES];
/* For each class, size of group of consecutive regs
that is needed for the reloads of this class. */
int group_size[N_REG_CLASSES];
/* For each class, max number of consecutive groups needed.
(Each group contains group_size[CLASS] consecutive registers.) */
int max_groups[N_REG_CLASSES];
/* For each class, max number needed of regs that don't belong
to any of the groups. */
int max_nongroups[N_REG_CLASSES];
/* For each class, the machine mode which requires consecutive
groups of regs of that class.
If two different modes ever require groups of one class,
they must be the same size and equally restrictive for that class,
otherwise we can't handle the complexity. */
enum machine_mode group_mode[N_REG_CLASSES];
/* Record the insn where each maximum need is first found. */
rtx max_needs_insn[N_REG_CLASSES];
rtx max_groups_insn[N_REG_CLASSES];
rtx max_nongroups_insn[N_REG_CLASSES];
rtx x; rtx x;
HOST_WIDE_INT starting_frame_size; HOST_WIDE_INT starting_frame_size;
#if HARD_FRAME_POINTER_REGNUM != FRAME_POINTER_REGNUM #if HARD_FRAME_POINTER_REGNUM != FRAME_POINTER_REGNUM
...@@ -907,13 +923,6 @@ reload (first, global, dumpfile) ...@@ -907,13 +923,6 @@ reload (first, global, dumpfile)
for (i = 0; i < N_REG_CLASSES; i++) for (i = 0; i < N_REG_CLASSES; i++)
group_mode[i] = VOIDmode; group_mode[i] = VOIDmode;
/* Keep track of which basic blocks are needing the reloads. */
this_block = 0;
/* Remember whether any element of basic_block_needs
changes from 0 to 1 in this pass. */
new_basic_block_needs = 0;
/* Round size of stack frame to BIGGEST_ALIGNMENT. This must be done /* Round size of stack frame to BIGGEST_ALIGNMENT. This must be done
here because the stack size may be a part of the offset computation here because the stack size may be a part of the offset computation
for register elimination, and there might have been new stack slots for register elimination, and there might have been new stack slots
...@@ -1025,511 +1034,7 @@ reload (first, global, dumpfile) ...@@ -1025,511 +1034,7 @@ reload (first, global, dumpfile)
group_size[(int) caller_save_spill_class] = caller_save_group_size; group_size[(int) caller_save_spill_class] = caller_save_group_size;
} }
/* Compute the most additional registers needed by any instruction. something_changed |= calculate_needs_all_insns (first, global);
Collect information separately for each class of regs. */
for (insn = first; insn; insn = NEXT_INSN (insn))
{
if (global && this_block + 1 < n_basic_blocks
&& insn == basic_block_head[this_block+1])
++this_block;
/* If this is a label, a JUMP_INSN, or has REG_NOTES (which
might include REG_LABEL), we need to see what effects this
has on the known offsets at labels. */
if (GET_CODE (insn) == CODE_LABEL || GET_CODE (insn) == JUMP_INSN
|| (GET_RTX_CLASS (GET_CODE (insn)) == 'i'
&& REG_NOTES (insn) != 0))
set_label_offsets (insn, insn, 0);
if (GET_RTX_CLASS (GET_CODE (insn)) == 'i')
{
/* Nonzero means don't use a reload reg that overlaps
the place where a function value can be returned. */
rtx avoid_return_reg = 0;
rtx old_body = PATTERN (insn);
int old_code = INSN_CODE (insn);
rtx old_notes = REG_NOTES (insn);
int did_elimination = 0;
/* To compute the number of reload registers of each class
needed for an insn, we must simulate what choose_reload_regs
can do. We do this by splitting an insn into an "input" and
an "output" part. RELOAD_OTHER reloads are used in both.
The input part uses those reloads, RELOAD_FOR_INPUT reloads,
which must be live over the entire input section of reloads,
and the maximum of all the RELOAD_FOR_INPUT_ADDRESS and
RELOAD_FOR_OPERAND_ADDRESS reloads, which conflict with the
inputs.
The registers needed for output are RELOAD_OTHER and
RELOAD_FOR_OUTPUT, which are live for the entire output
portion, and the maximum of all the RELOAD_FOR_OUTPUT_ADDRESS
reloads for each operand.
The total number of registers needed is the maximum of the
inputs and outputs. */
struct needs
{
/* [0] is normal, [1] is nongroup. */
int regs[2][N_REG_CLASSES];
int groups[N_REG_CLASSES];
};
/* Each `struct needs' corresponds to one RELOAD_... type. */
struct {
struct needs other;
struct needs input;
struct needs output;
struct needs insn;
struct needs other_addr;
struct needs op_addr;
struct needs op_addr_reload;
struct needs in_addr[MAX_RECOG_OPERANDS];
struct needs in_addr_addr[MAX_RECOG_OPERANDS];
struct needs out_addr[MAX_RECOG_OPERANDS];
struct needs out_addr_addr[MAX_RECOG_OPERANDS];
} insn_needs;
/* If needed, eliminate any eliminable registers. */
if (num_eliminable)
did_elimination = eliminate_regs_in_insn (insn, 0);
/* Set avoid_return_reg if this is an insn
that might use the value of a function call. */
if (SMALL_REGISTER_CLASSES && GET_CODE (insn) == CALL_INSN)
{
if (GET_CODE (PATTERN (insn)) == SET)
after_call = SET_DEST (PATTERN (insn));
else if (GET_CODE (PATTERN (insn)) == PARALLEL
&& GET_CODE (XVECEXP (PATTERN (insn), 0, 0)) == SET)
after_call = SET_DEST (XVECEXP (PATTERN (insn), 0, 0));
else
after_call = 0;
}
else if (SMALL_REGISTER_CLASSES && after_call != 0
&& !(GET_CODE (PATTERN (insn)) == SET
&& SET_DEST (PATTERN (insn)) == stack_pointer_rtx)
&& GET_CODE (PATTERN (insn)) != USE)
{
if (reg_referenced_p (after_call, PATTERN (insn)))
avoid_return_reg = after_call;
after_call = 0;
}
/* Analyze the instruction. */
find_reloads (insn, 0, spill_indirect_levels, global,
spill_reg_order);
/* Remember for later shortcuts which insns had any reloads or
register eliminations.
One might think that it would be worthwhile to mark insns
that need register replacements but not reloads, but this is
not safe because find_reloads may do some manipulation of
the insn (such as swapping commutative operands), which would
be lost when we restore the old pattern after register
replacement. So the actions of find_reloads must be redone in
subsequent passes or in reload_as_needed.
However, it is safe to mark insns that need reloads
but not register replacement. */
PUT_MODE (insn, (did_elimination ? QImode
: n_reloads ? HImode
: GET_MODE (insn) == DImode ? DImode
: VOIDmode));
/* Discard any register replacements done. */
if (did_elimination)
{
obstack_free (&reload_obstack, reload_firstobj);
PATTERN (insn) = old_body;
INSN_CODE (insn) = old_code;
REG_NOTES (insn) = old_notes;
something_needs_elimination = 1;
}
/* If this insn has no reloads, we need not do anything except
in the case of a CALL_INSN when we have caller-saves and
caller-save needs reloads. */
if (n_reloads == 0
&& ! (GET_CODE (insn) == CALL_INSN
&& caller_save_spill_class != NO_REGS))
continue;
something_needs_reloads = 1;
bzero ((char *) &insn_needs, sizeof insn_needs);
/* Count each reload once in every class
containing the reload's own class. */
for (i = 0; i < n_reloads; i++)
{
register enum reg_class *p;
enum reg_class class = reload_reg_class[i];
int size;
enum machine_mode mode;
struct needs *this_needs;
/* Don't count the dummy reloads, for which one of the
regs mentioned in the insn can be used for reloading.
Don't count optional reloads.
Don't count reloads that got combined with others. */
if (reload_reg_rtx[i] != 0
|| reload_optional[i] != 0
|| (reload_out[i] == 0 && reload_in[i] == 0
&& ! reload_secondary_p[i]))
continue;
/* Show that a reload register of this class is needed
in this basic block. We do not use insn_needs and
insn_groups because they are overly conservative for
this purpose. */
if (global && ! basic_block_needs[(int) class][this_block])
{
basic_block_needs[(int) class][this_block] = 1;
new_basic_block_needs = 1;
}
mode = reload_inmode[i];
if (GET_MODE_SIZE (reload_outmode[i]) > GET_MODE_SIZE (mode))
mode = reload_outmode[i];
size = CLASS_MAX_NREGS (class, mode);
/* Decide which time-of-use to count this reload for. */
switch (reload_when_needed[i])
{
case RELOAD_OTHER:
this_needs = &insn_needs.other;
break;
case RELOAD_FOR_INPUT:
this_needs = &insn_needs.input;
break;
case RELOAD_FOR_OUTPUT:
this_needs = &insn_needs.output;
break;
case RELOAD_FOR_INSN:
this_needs = &insn_needs.insn;
break;
case RELOAD_FOR_OTHER_ADDRESS:
this_needs = &insn_needs.other_addr;
break;
case RELOAD_FOR_INPUT_ADDRESS:
this_needs = &insn_needs.in_addr[reload_opnum[i]];
break;
case RELOAD_FOR_INPADDR_ADDRESS:
this_needs = &insn_needs.in_addr_addr[reload_opnum[i]];
break;
case RELOAD_FOR_OUTPUT_ADDRESS:
this_needs = &insn_needs.out_addr[reload_opnum[i]];
break;
case RELOAD_FOR_OUTADDR_ADDRESS:
this_needs = &insn_needs.out_addr_addr[reload_opnum[i]];
break;
case RELOAD_FOR_OPERAND_ADDRESS:
this_needs = &insn_needs.op_addr;
break;
case RELOAD_FOR_OPADDR_ADDR:
this_needs = &insn_needs.op_addr_reload;
break;
}
if (size > 1)
{
enum machine_mode other_mode, allocate_mode;
/* Count number of groups needed separately from
number of individual regs needed. */
this_needs->groups[(int) class]++;
p = reg_class_superclasses[(int) class];
while (*p != LIM_REG_CLASSES)
this_needs->groups[(int) *p++]++;
/* Record size and mode of a group of this class. */
/* If more than one size group is needed,
make all groups the largest needed size. */
if (group_size[(int) class] < size)
{
other_mode = group_mode[(int) class];
allocate_mode = mode;
group_size[(int) class] = size;
group_mode[(int) class] = mode;
}
else
{
other_mode = mode;
allocate_mode = group_mode[(int) class];
}
/* Crash if two dissimilar machine modes both need
groups of consecutive regs of the same class. */
if (other_mode != VOIDmode && other_mode != allocate_mode
&& ! modes_equiv_for_class_p (allocate_mode,
other_mode, class))
fatal_insn ("Two dissimilar machine modes both need groups of consecutive regs of the same class",
insn);
}
else if (size == 1)
{
this_needs->regs[reload_nongroup[i]][(int) class] += 1;
p = reg_class_superclasses[(int) class];
while (*p != LIM_REG_CLASSES)
this_needs->regs[reload_nongroup[i]][(int) *p++] += 1;
}
else
abort ();
}
/* All reloads have been counted for this insn;
now merge the various times of use.
This sets insn_needs, etc., to the maximum total number
of registers needed at any point in this insn. */
for (i = 0; i < N_REG_CLASSES; i++)
{
int in_max, out_max;
/* Compute normal and nongroup needs. */
for (j = 0; j <= 1; j++)
{
for (in_max = 0, out_max = 0, k = 0;
k < reload_n_operands; k++)
{
in_max
= MAX (in_max,
(insn_needs.in_addr[k].regs[j][i]
+ insn_needs.in_addr_addr[k].regs[j][i]));
out_max
= MAX (out_max, insn_needs.out_addr[k].regs[j][i]);
out_max
= MAX (out_max,
insn_needs.out_addr_addr[k].regs[j][i]);
}
/* RELOAD_FOR_INSN reloads conflict with inputs, outputs,
and operand addresses but not things used to reload
them. Similarly, RELOAD_FOR_OPERAND_ADDRESS reloads
don't conflict with things needed to reload inputs or
outputs. */
in_max = MAX (MAX (insn_needs.op_addr.regs[j][i],
insn_needs.op_addr_reload.regs[j][i]),
in_max);
out_max = MAX (out_max, insn_needs.insn.regs[j][i]);
insn_needs.input.regs[j][i]
= MAX (insn_needs.input.regs[j][i]
+ insn_needs.op_addr.regs[j][i]
+ insn_needs.insn.regs[j][i],
in_max + insn_needs.input.regs[j][i]);
insn_needs.output.regs[j][i] += out_max;
insn_needs.other.regs[j][i]
+= MAX (MAX (insn_needs.input.regs[j][i],
insn_needs.output.regs[j][i]),
insn_needs.other_addr.regs[j][i]);
}
/* Now compute group needs. */
for (in_max = 0, out_max = 0, j = 0;
j < reload_n_operands; j++)
{
in_max = MAX (in_max, insn_needs.in_addr[j].groups[i]);
in_max = MAX (in_max,
insn_needs.in_addr_addr[j].groups[i]);
out_max
= MAX (out_max, insn_needs.out_addr[j].groups[i]);
out_max
= MAX (out_max, insn_needs.out_addr_addr[j].groups[i]);
}
in_max = MAX (MAX (insn_needs.op_addr.groups[i],
insn_needs.op_addr_reload.groups[i]),
in_max);
out_max = MAX (out_max, insn_needs.insn.groups[i]);
insn_needs.input.groups[i]
= MAX (insn_needs.input.groups[i]
+ insn_needs.op_addr.groups[i]
+ insn_needs.insn.groups[i],
in_max + insn_needs.input.groups[i]);
insn_needs.output.groups[i] += out_max;
insn_needs.other.groups[i]
+= MAX (MAX (insn_needs.input.groups[i],
insn_needs.output.groups[i]),
insn_needs.other_addr.groups[i]);
}
/* If this is a CALL_INSN and caller-saves will need
a spill register, act as if the spill register is
needed for this insn. However, the spill register
can be used by any reload of this insn, so we only
need do something if no need for that class has
been recorded.
The assumption that every CALL_INSN will trigger a
caller-save is highly conservative, however, the number
of cases where caller-saves will need a spill register but
a block containing a CALL_INSN won't need a spill register
of that class should be quite rare.
If a group is needed, the size and mode of the group will
have been set up at the beginning of this loop. */
if (GET_CODE (insn) == CALL_INSN
&& caller_save_spill_class != NO_REGS)
{
/* See if this register would conflict with any reload that
needs a group or any reload that needs a nongroup. */
int nongroup_need = 0;
int *caller_save_needs;
for (j = 0; j < n_reloads; j++)
if (reg_classes_intersect_p (caller_save_spill_class,
reload_reg_class[j])
&& ((CLASS_MAX_NREGS
(reload_reg_class[j],
(GET_MODE_SIZE (reload_outmode[j])
> GET_MODE_SIZE (reload_inmode[j]))
? reload_outmode[j] : reload_inmode[j])
> 1)
|| reload_nongroup[j]))
{
nongroup_need = 1;
break;
}
caller_save_needs
= (caller_save_group_size > 1
? insn_needs.other.groups
: insn_needs.other.regs[nongroup_need]);
if (caller_save_needs[(int) caller_save_spill_class] == 0)
{
register enum reg_class *p
= reg_class_superclasses[(int) caller_save_spill_class];
caller_save_needs[(int) caller_save_spill_class]++;
while (*p != LIM_REG_CLASSES)
caller_save_needs[(int) *p++] += 1;
}
/* Show that this basic block will need a register of
this class. */
if (global
&& ! (basic_block_needs[(int) caller_save_spill_class]
[this_block]))
{
basic_block_needs[(int) caller_save_spill_class]
[this_block] = 1;
new_basic_block_needs = 1;
}
}
/* If this insn stores the value of a function call,
and that value is in a register that has been spilled,
and if the insn needs a reload in a class
that might use that register as the reload register,
then add an extra need in that class.
This makes sure we have a register available that does
not overlap the return value. */
if (SMALL_REGISTER_CLASSES && avoid_return_reg)
{
int regno = REGNO (avoid_return_reg);
int nregs
= HARD_REGNO_NREGS (regno, GET_MODE (avoid_return_reg));
int r;
int basic_needs[N_REG_CLASSES], basic_groups[N_REG_CLASSES];
/* First compute the "basic needs", which counts a
need only in the smallest class in which it
is required. */
bcopy ((char *) insn_needs.other.regs[0],
(char *) basic_needs, sizeof basic_needs);
bcopy ((char *) insn_needs.other.groups,
(char *) basic_groups, sizeof basic_groups);
for (i = 0; i < N_REG_CLASSES; i++)
{
enum reg_class *p;
if (basic_needs[i] >= 0)
for (p = reg_class_superclasses[i];
*p != LIM_REG_CLASSES; p++)
basic_needs[(int) *p] -= basic_needs[i];
if (basic_groups[i] >= 0)
for (p = reg_class_superclasses[i];
*p != LIM_REG_CLASSES; p++)
basic_groups[(int) *p] -= basic_groups[i];
}
/* Now count extra regs if there might be a conflict with
the return value register. */
for (r = regno; r < regno + nregs; r++)
if (spill_reg_order[r] >= 0)
for (i = 0; i < N_REG_CLASSES; i++)
if (TEST_HARD_REG_BIT (reg_class_contents[i], r))
{
if (basic_needs[i] > 0)
{
enum reg_class *p;
insn_needs.other.regs[0][i]++;
p = reg_class_superclasses[i];
while (*p != LIM_REG_CLASSES)
insn_needs.other.regs[0][(int) *p++]++;
}
if (basic_groups[i] > 0)
{
enum reg_class *p;
insn_needs.other.groups[i]++;
p = reg_class_superclasses[i];
while (*p != LIM_REG_CLASSES)
insn_needs.other.groups[(int) *p++]++;
}
}
}
/* For each class, collect maximum need of any insn. */
for (i = 0; i < N_REG_CLASSES; i++)
{
if (max_needs[i] < insn_needs.other.regs[0][i])
{
max_needs[i] = insn_needs.other.regs[0][i];
max_needs_insn[i] = insn;
}
if (max_groups[i] < insn_needs.other.groups[i])
{
max_groups[i] = insn_needs.other.groups[i];
max_groups_insn[i] = insn;
}
if (max_nongroups[i] < insn_needs.other.regs[1][i])
{
max_nongroups[i] = insn_needs.other.regs[1][i];
max_nongroups_insn[i] = insn;
}
}
}
/* Note that there is a continue statement above. */
}
/* If we allocated any new memory locations, make another pass /* If we allocated any new memory locations, make another pass
since it might have changed elimination offsets. */ since it might have changed elimination offsets. */
...@@ -1556,7 +1061,7 @@ reload (first, global, dumpfile) ...@@ -1556,7 +1061,7 @@ reload (first, global, dumpfile)
mode_name[(int) group_mode[i]], mode_name[(int) group_mode[i]],
reg_class_names[i], INSN_UID (max_groups_insn[i])); reg_class_names[i], INSN_UID (max_groups_insn[i]));
} }
/* If we have caller-saves, set up the save areas and see if caller-save /* If we have caller-saves, set up the save areas and see if caller-save
will need a spill register. */ will need a spill register. */
...@@ -1666,7 +1171,7 @@ reload (first, global, dumpfile) ...@@ -1666,7 +1171,7 @@ reload (first, global, dumpfile)
for (i = 0; i < N_REG_CLASSES; i++) for (i = 0; i < N_REG_CLASSES; i++)
if (max_needs[i] > 0 || max_groups[i] > 0 || max_nongroups[i] > 0) if (max_needs[i] > 0 || max_groups[i] > 0 || max_nongroups[i] > 0)
break; break;
if (i == N_REG_CLASSES && !new_basic_block_needs && ! something_changed) if (i == N_REG_CLASSES && ! something_changed)
break; break;
/* Not all needs are met; must spill some hard regs. */ /* Not all needs are met; must spill some hard regs. */
...@@ -1708,305 +1213,9 @@ reload (first, global, dumpfile) ...@@ -1708,305 +1213,9 @@ reload (first, global, dumpfile)
n_spills = 0; n_spills = 0;
} }
/* Now find more reload regs to satisfy the remaining need something_changed |= find_reload_regs (global, dumpfile);
Do it by ascending class number, since otherwise a reg if (failure)
might be spilled for a big class and might fail to count goto failed;
for a smaller class even though it belongs to that class.
Count spilled regs in `spills', and add entries to
`spill_regs' and `spill_reg_order'.
??? Note there is a problem here.
When there is a need for a group in a high-numbered class,
and also need for non-group regs that come from a lower class,
the non-group regs are chosen first. If there aren't many regs,
they might leave no room for a group.
This was happening on the 386. To fix it, we added the code
that calls possible_group_p, so that the lower class won't
break up the last possible group.
Really fixing the problem would require changes above
in counting the regs already spilled, and in choose_reload_regs.
It might be hard to avoid introducing bugs there. */
CLEAR_HARD_REG_SET (counted_for_groups);
CLEAR_HARD_REG_SET (counted_for_nongroups);
for (class = 0; class < N_REG_CLASSES; class++)
{
/* First get the groups of registers.
If we got single registers first, we might fragment
possible groups. */
while (max_groups[class] > 0)
{
/* If any single spilled regs happen to form groups,
count them now. Maybe we don't really need
to spill another group. */
count_possible_groups (group_size, group_mode, max_groups,
class);
if (max_groups[class] <= 0)
break;
/* Groups of size 2 (the only groups used on most machines)
are treated specially. */
if (group_size[class] == 2)
{
/* First, look for a register that will complete a group. */
for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
{
int other;
j = potential_reload_regs[i];
if (j >= 0 && ! TEST_HARD_REG_BIT (bad_spill_regs, j)
&&
((j > 0 && (other = j - 1, spill_reg_order[other] >= 0)
&& TEST_HARD_REG_BIT (reg_class_contents[class], j)
&& TEST_HARD_REG_BIT (reg_class_contents[class], other)
&& HARD_REGNO_MODE_OK (other, group_mode[class])
&& ! TEST_HARD_REG_BIT (counted_for_nongroups,
other)
/* We don't want one part of another group.
We could get "two groups" that overlap! */
&& ! TEST_HARD_REG_BIT (counted_for_groups, other))
||
(j < FIRST_PSEUDO_REGISTER - 1
&& (other = j + 1, spill_reg_order[other] >= 0)
&& TEST_HARD_REG_BIT (reg_class_contents[class], j)
&& TEST_HARD_REG_BIT (reg_class_contents[class], other)
&& HARD_REGNO_MODE_OK (j, group_mode[class])
&& ! TEST_HARD_REG_BIT (counted_for_nongroups,
other)
&& ! TEST_HARD_REG_BIT (counted_for_groups,
other))))
{
register enum reg_class *p;
/* We have found one that will complete a group,
so count off one group as provided. */
max_groups[class]--;
p = reg_class_superclasses[class];
while (*p != LIM_REG_CLASSES)
{
if (group_size [(int) *p] <= group_size [class])
max_groups[(int) *p]--;
p++;
}
/* Indicate both these regs are part of a group. */
SET_HARD_REG_BIT (counted_for_groups, j);
SET_HARD_REG_BIT (counted_for_groups, other);
break;
}
}
/* We can't complete a group, so start one. */
/* Look for a pair neither of which is explicitly used. */
if (SMALL_REGISTER_CLASSES && i == FIRST_PSEUDO_REGISTER)
for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
{
int k;
j = potential_reload_regs[i];
/* Verify that J+1 is a potential reload reg. */
for (k = 0; k < FIRST_PSEUDO_REGISTER; k++)
if (potential_reload_regs[k] == j + 1)
break;
if (j >= 0 && j + 1 < FIRST_PSEUDO_REGISTER
&& k < FIRST_PSEUDO_REGISTER
&& spill_reg_order[j] < 0 && spill_reg_order[j + 1] < 0
&& TEST_HARD_REG_BIT (reg_class_contents[class], j)
&& TEST_HARD_REG_BIT (reg_class_contents[class], j + 1)
&& HARD_REGNO_MODE_OK (j, group_mode[class])
&& ! TEST_HARD_REG_BIT (counted_for_nongroups,
j + 1)
&& ! TEST_HARD_REG_BIT (bad_spill_regs, j + 1)
/* Reject J at this stage
if J+1 was explicitly used. */
&& ! regs_explicitly_used[j + 1])
break;
}
/* Now try any group at all
whose registers are not in bad_spill_regs. */
if (i == FIRST_PSEUDO_REGISTER)
for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
{
int k;
j = potential_reload_regs[i];
/* Verify that J+1 is a potential reload reg. */
for (k = 0; k < FIRST_PSEUDO_REGISTER; k++)
if (potential_reload_regs[k] == j + 1)
break;
if (j >= 0 && j + 1 < FIRST_PSEUDO_REGISTER
&& k < FIRST_PSEUDO_REGISTER
&& spill_reg_order[j] < 0 && spill_reg_order[j + 1] < 0
&& TEST_HARD_REG_BIT (reg_class_contents[class], j)
&& TEST_HARD_REG_BIT (reg_class_contents[class], j + 1)
&& HARD_REGNO_MODE_OK (j, group_mode[class])
&& ! TEST_HARD_REG_BIT (counted_for_nongroups,
j + 1)
&& ! TEST_HARD_REG_BIT (bad_spill_regs, j + 1))
break;
}
/* I should be the index in potential_reload_regs
of the new reload reg we have found. */
if (i >= FIRST_PSEUDO_REGISTER)
{
/* There are no groups left to spill. */
spill_failure (max_groups_insn[class]);
failure = 1;
goto failed;
}
else
something_changed
|= new_spill_reg (i, class, max_needs, NULL_PTR,
global, dumpfile);
}
else
{
/* For groups of more than 2 registers,
look for a sufficient sequence of unspilled registers,
and spill them all at once. */
for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
{
int k;
j = potential_reload_regs[i];
if (j >= 0
&& j + group_size[class] <= FIRST_PSEUDO_REGISTER
&& HARD_REGNO_MODE_OK (j, group_mode[class]))
{
/* Check each reg in the sequence. */
for (k = 0; k < group_size[class]; k++)
if (! (spill_reg_order[j + k] < 0
&& ! TEST_HARD_REG_BIT (bad_spill_regs, j + k)
&& TEST_HARD_REG_BIT (reg_class_contents[class], j + k)))
break;
/* We got a full sequence, so spill them all. */
if (k == group_size[class])
{
register enum reg_class *p;
for (k = 0; k < group_size[class]; k++)
{
int idx;
SET_HARD_REG_BIT (counted_for_groups, j + k);
for (idx = 0; idx < FIRST_PSEUDO_REGISTER; idx++)
if (potential_reload_regs[idx] == j + k)
break;
something_changed
|= new_spill_reg (idx, class,
max_needs, NULL_PTR,
global, dumpfile);
}
/* We have found one that will complete a group,
so count off one group as provided. */
max_groups[class]--;
p = reg_class_superclasses[class];
while (*p != LIM_REG_CLASSES)
{
if (group_size [(int) *p]
<= group_size [class])
max_groups[(int) *p]--;
p++;
}
break;
}
}
}
/* We couldn't find any registers for this reload.
Avoid going into an infinite loop. */
if (i >= FIRST_PSEUDO_REGISTER)
{
/* There are no groups left. */
spill_failure (max_groups_insn[class]);
failure = 1;
goto failed;
}
}
}
/* Now similarly satisfy all need for single registers. */
while (max_needs[class] > 0 || max_nongroups[class] > 0)
{
/* If we spilled enough regs, but they weren't counted
against the non-group need, see if we can count them now.
If so, we can avoid some actual spilling. */
if (max_needs[class] <= 0 && max_nongroups[class] > 0)
for (i = 0; i < n_spills; i++)
if (TEST_HARD_REG_BIT (reg_class_contents[class],
spill_regs[i])
&& !TEST_HARD_REG_BIT (counted_for_groups,
spill_regs[i])
&& !TEST_HARD_REG_BIT (counted_for_nongroups,
spill_regs[i])
&& max_nongroups[class] > 0)
{
register enum reg_class *p;
SET_HARD_REG_BIT (counted_for_nongroups, spill_regs[i]);
max_nongroups[class]--;
p = reg_class_superclasses[class];
while (*p != LIM_REG_CLASSES)
max_nongroups[(int) *p++]--;
}
if (max_needs[class] <= 0 && max_nongroups[class] <= 0)
break;
/* Consider the potential reload regs that aren't
yet in use as reload regs, in order of preference.
Find the most preferred one that's in this class. */
for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
if (potential_reload_regs[i] >= 0
&& TEST_HARD_REG_BIT (reg_class_contents[class],
potential_reload_regs[i])
/* If this reg will not be available for groups,
pick one that does not foreclose possible groups.
This is a kludge, and not very general,
but it should be sufficient to make the 386 work,
and the problem should not occur on machines with
more registers. */
&& (max_nongroups[class] == 0
|| possible_group_p (potential_reload_regs[i], max_groups)))
break;
/* If we couldn't get a register, try to get one even if we
might foreclose possible groups. This may cause problems
later, but that's better than aborting now, since it is
possible that we will, in fact, be able to form the needed
group even with this allocation. */
if (i >= FIRST_PSEUDO_REGISTER
&& (asm_noperands (max_needs[class] > 0
? max_needs_insn[class]
: max_nongroups_insn[class])
< 0))
for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
if (potential_reload_regs[i] >= 0
&& TEST_HARD_REG_BIT (reg_class_contents[class],
potential_reload_regs[i]))
break;
/* I should be the index in potential_reload_regs
of the new reload reg we have found. */
if (i >= FIRST_PSEUDO_REGISTER)
{
/* There are no possible registers left to spill. */
spill_failure (max_needs[class] > 0 ? max_needs_insn[class]
: max_nongroups_insn[class]);
failure = 1;
goto failed;
}
else
something_changed
|= new_spill_reg (i, class, max_needs, max_nongroups,
global, dumpfile);
}
}
} }
/* If global-alloc was run, notify it of any register eliminations we have /* If global-alloc was run, notify it of any register eliminations we have
...@@ -2195,6 +1404,863 @@ reload (first, global, dumpfile) ...@@ -2195,6 +1404,863 @@ reload (first, global, dumpfile)
return failure; return failure;
} }
/* Walk the insns of the current function, starting with FIRST, and collect
information about the need to do register elimination and the need to
perform reloads. */
static int
calculate_needs_all_insns (first, global)
rtx first;
int global;
{
rtx insn;
int something_changed = 0;
rtx after_call = 0;
/* Keep track of which basic blocks are needing the reloads. */
int this_block = 0;
/* Compute the most additional registers needed by any instruction.
Collect information separately for each class of regs. */
for (insn = first; insn; insn = NEXT_INSN (insn))
{
if (global && this_block + 1 < n_basic_blocks
&& insn == basic_block_head[this_block+1])
++this_block;
/* If this is a label, a JUMP_INSN, or has REG_NOTES (which
might include REG_LABEL), we need to see what effects this
has on the known offsets at labels. */
if (GET_CODE (insn) == CODE_LABEL || GET_CODE (insn) == JUMP_INSN
|| (GET_RTX_CLASS (GET_CODE (insn)) == 'i'
&& REG_NOTES (insn) != 0))
set_label_offsets (insn, insn, 0);
if (GET_RTX_CLASS (GET_CODE (insn)) == 'i')
{
rtx old_body = PATTERN (insn);
int old_code = INSN_CODE (insn);
rtx old_notes = REG_NOTES (insn);
int did_elimination = 0;
/* Nonzero means don't use a reload reg that overlaps
the place where a function value can be returned. */
rtx avoid_return_reg = 0;
/* Set avoid_return_reg if this is an insn
that might use the value of a function call. */
if (SMALL_REGISTER_CLASSES && GET_CODE (insn) == CALL_INSN)
{
if (GET_CODE (PATTERN (insn)) == SET)
after_call = SET_DEST (PATTERN (insn));
else if (GET_CODE (PATTERN (insn)) == PARALLEL
&& GET_CODE (XVECEXP (PATTERN (insn), 0, 0)) == SET)
after_call = SET_DEST (XVECEXP (PATTERN (insn), 0, 0));
else
after_call = 0;
}
else if (SMALL_REGISTER_CLASSES && after_call != 0
&& !(GET_CODE (PATTERN (insn)) == SET
&& SET_DEST (PATTERN (insn)) == stack_pointer_rtx)
&& GET_CODE (PATTERN (insn)) != USE)
{
if (reg_referenced_p (after_call, PATTERN (insn)))
avoid_return_reg = after_call;
after_call = 0;
}
/* If needed, eliminate any eliminable registers. */
if (num_eliminable)
did_elimination = eliminate_regs_in_insn (insn, 0);
/* Analyze the instruction. */
find_reloads (insn, 0, spill_indirect_levels, global,
spill_reg_order);
/* Remember for later shortcuts which insns had any reloads or
register eliminations.
One might think that it would be worthwhile to mark insns
that need register replacements but not reloads, but this is
not safe because find_reloads may do some manipulation of
the insn (such as swapping commutative operands), which would
be lost when we restore the old pattern after register
replacement. So the actions of find_reloads must be redone in
subsequent passes or in reload_as_needed.
However, it is safe to mark insns that need reloads
but not register replacement. */
PUT_MODE (insn, (did_elimination ? QImode
: n_reloads ? HImode
: GET_MODE (insn) == DImode ? DImode
: VOIDmode));
/* Discard any register replacements done. */
if (did_elimination)
{
obstack_free (&reload_obstack, reload_firstobj);
PATTERN (insn) = old_body;
INSN_CODE (insn) = old_code;
REG_NOTES (insn) = old_notes;
something_needs_elimination = 1;
}
/* If this insn has no reloads, we need not do anything except
in the case of a CALL_INSN when we have caller-saves and
caller-save needs reloads. */
if (n_reloads != 0
|| (GET_CODE (insn) == CALL_INSN
&& caller_save_spill_class != NO_REGS))
something_changed |= calculate_needs (this_block, insn,
avoid_return_reg, global);
}
/* Note that there is a continue statement above. */
}
return something_changed;
}
/* To compute the number of reload registers of each class
needed for an insn, we must simulate what choose_reload_regs
can do. We do this by splitting an insn into an "input" and
an "output" part. RELOAD_OTHER reloads are used in both.
The input part uses those reloads, RELOAD_FOR_INPUT reloads,
which must be live over the entire input section of reloads,
and the maximum of all the RELOAD_FOR_INPUT_ADDRESS and
RELOAD_FOR_OPERAND_ADDRESS reloads, which conflict with the
inputs.
The registers needed for output are RELOAD_OTHER and
RELOAD_FOR_OUTPUT, which are live for the entire output
portion, and the maximum of all the RELOAD_FOR_OUTPUT_ADDRESS
reloads for each operand.
The total number of registers needed is the maximum of the
inputs and outputs. */
static int
calculate_needs (this_block, insn, avoid_return_reg, global)
int this_block;
rtx insn, avoid_return_reg;
int global;
{
int something_changed = 0;
int i;
struct needs
{
/* [0] is normal, [1] is nongroup. */
int regs[2][N_REG_CLASSES];
int groups[N_REG_CLASSES];
};
/* Each `struct needs' corresponds to one RELOAD_... type. */
struct {
struct needs other;
struct needs input;
struct needs output;
struct needs insn;
struct needs other_addr;
struct needs op_addr;
struct needs op_addr_reload;
struct needs in_addr[MAX_RECOG_OPERANDS];
struct needs in_addr_addr[MAX_RECOG_OPERANDS];
struct needs out_addr[MAX_RECOG_OPERANDS];
struct needs out_addr_addr[MAX_RECOG_OPERANDS];
} insn_needs;
something_needs_reloads = 1;
bzero ((char *) &insn_needs, sizeof insn_needs);
/* Count each reload once in every class
containing the reload's own class. */
for (i = 0; i < n_reloads; i++)
{
register enum reg_class *p;
enum reg_class class = reload_reg_class[i];
int size;
enum machine_mode mode;
struct needs *this_needs;
/* Don't count the dummy reloads, for which one of the
regs mentioned in the insn can be used for reloading.
Don't count optional reloads.
Don't count reloads that got combined with others. */
if (reload_reg_rtx[i] != 0
|| reload_optional[i] != 0
|| (reload_out[i] == 0 && reload_in[i] == 0
&& ! reload_secondary_p[i]))
continue;
/* Show that a reload register of this class is needed
in this basic block. We do not use insn_needs and
insn_groups because they are overly conservative for
this purpose. */
if (global && ! basic_block_needs[(int) class][this_block])
{
basic_block_needs[(int) class][this_block] = 1;
something_changed = 1;
}
mode = reload_inmode[i];
if (GET_MODE_SIZE (reload_outmode[i]) > GET_MODE_SIZE (mode))
mode = reload_outmode[i];
size = CLASS_MAX_NREGS (class, mode);
/* Decide which time-of-use to count this reload for. */
switch (reload_when_needed[i])
{
case RELOAD_OTHER:
this_needs = &insn_needs.other;
break;
case RELOAD_FOR_INPUT:
this_needs = &insn_needs.input;
break;
case RELOAD_FOR_OUTPUT:
this_needs = &insn_needs.output;
break;
case RELOAD_FOR_INSN:
this_needs = &insn_needs.insn;
break;
case RELOAD_FOR_OTHER_ADDRESS:
this_needs = &insn_needs.other_addr;
break;
case RELOAD_FOR_INPUT_ADDRESS:
this_needs = &insn_needs.in_addr[reload_opnum[i]];
break;
case RELOAD_FOR_INPADDR_ADDRESS:
this_needs = &insn_needs.in_addr_addr[reload_opnum[i]];
break;
case RELOAD_FOR_OUTPUT_ADDRESS:
this_needs = &insn_needs.out_addr[reload_opnum[i]];
break;
case RELOAD_FOR_OUTADDR_ADDRESS:
this_needs = &insn_needs.out_addr_addr[reload_opnum[i]];
break;
case RELOAD_FOR_OPERAND_ADDRESS:
this_needs = &insn_needs.op_addr;
break;
case RELOAD_FOR_OPADDR_ADDR:
this_needs = &insn_needs.op_addr_reload;
break;
}
if (size > 1)
{
enum machine_mode other_mode, allocate_mode;
/* Count number of groups needed separately from
number of individual regs needed. */
this_needs->groups[(int) class]++;
p = reg_class_superclasses[(int) class];
while (*p != LIM_REG_CLASSES)
this_needs->groups[(int) *p++]++;
/* Record size and mode of a group of this class. */
/* If more than one size group is needed,
make all groups the largest needed size. */
if (group_size[(int) class] < size)
{
other_mode = group_mode[(int) class];
allocate_mode = mode;
group_size[(int) class] = size;
group_mode[(int) class] = mode;
}
else
{
other_mode = mode;
allocate_mode = group_mode[(int) class];
}
/* Crash if two dissimilar machine modes both need
groups of consecutive regs of the same class. */
if (other_mode != VOIDmode && other_mode != allocate_mode
&& ! modes_equiv_for_class_p (allocate_mode,
other_mode, class))
fatal_insn ("Two dissimilar machine modes both need groups of consecutive regs of the same class",
insn);
}
else if (size == 1)
{
this_needs->regs[reload_nongroup[i]][(int) class] += 1;
p = reg_class_superclasses[(int) class];
while (*p != LIM_REG_CLASSES)
this_needs->regs[reload_nongroup[i]][(int) *p++] += 1;
}
else
abort ();
}
/* All reloads have been counted for this insn;
now merge the various times of use.
This sets insn_needs, etc., to the maximum total number
of registers needed at any point in this insn. */
for (i = 0; i < N_REG_CLASSES; i++)
{
int j, in_max, out_max;
/* Compute normal and nongroup needs. */
for (j = 0; j <= 1; j++)
{
int k;
for (in_max = 0, out_max = 0, k = 0; k < reload_n_operands; k++)
{
in_max = MAX (in_max,
(insn_needs.in_addr[k].regs[j][i]
+ insn_needs.in_addr_addr[k].regs[j][i]));
out_max = MAX (out_max, insn_needs.out_addr[k].regs[j][i]);
out_max = MAX (out_max,
insn_needs.out_addr_addr[k].regs[j][i]);
}
/* RELOAD_FOR_INSN reloads conflict with inputs, outputs,
and operand addresses but not things used to reload
them. Similarly, RELOAD_FOR_OPERAND_ADDRESS reloads
don't conflict with things needed to reload inputs or
outputs. */
in_max = MAX (MAX (insn_needs.op_addr.regs[j][i],
insn_needs.op_addr_reload.regs[j][i]),
in_max);
out_max = MAX (out_max, insn_needs.insn.regs[j][i]);
insn_needs.input.regs[j][i]
= MAX (insn_needs.input.regs[j][i]
+ insn_needs.op_addr.regs[j][i]
+ insn_needs.insn.regs[j][i],
in_max + insn_needs.input.regs[j][i]);
insn_needs.output.regs[j][i] += out_max;
insn_needs.other.regs[j][i]
+= MAX (MAX (insn_needs.input.regs[j][i],
insn_needs.output.regs[j][i]),
insn_needs.other_addr.regs[j][i]);
}
/* Now compute group needs. */
for (in_max = 0, out_max = 0, j = 0; j < reload_n_operands; j++)
{
in_max = MAX (in_max, insn_needs.in_addr[j].groups[i]);
in_max = MAX (in_max, insn_needs.in_addr_addr[j].groups[i]);
out_max = MAX (out_max, insn_needs.out_addr[j].groups[i]);
out_max = MAX (out_max, insn_needs.out_addr_addr[j].groups[i]);
}
in_max = MAX (MAX (insn_needs.op_addr.groups[i],
insn_needs.op_addr_reload.groups[i]),
in_max);
out_max = MAX (out_max, insn_needs.insn.groups[i]);
insn_needs.input.groups[i]
= MAX (insn_needs.input.groups[i]
+ insn_needs.op_addr.groups[i]
+ insn_needs.insn.groups[i],
in_max + insn_needs.input.groups[i]);
insn_needs.output.groups[i] += out_max;
insn_needs.other.groups[i]
+= MAX (MAX (insn_needs.input.groups[i],
insn_needs.output.groups[i]),
insn_needs.other_addr.groups[i]);
}
/* If this is a CALL_INSN and caller-saves will need
a spill register, act as if the spill register is
needed for this insn. However, the spill register
can be used by any reload of this insn, so we only
need do something if no need for that class has
been recorded.
The assumption that every CALL_INSN will trigger a
caller-save is highly conservative, however, the number
of cases where caller-saves will need a spill register but
a block containing a CALL_INSN won't need a spill register
of that class should be quite rare.
If a group is needed, the size and mode of the group will
have been set up at the beginning of this loop. */
if (GET_CODE (insn) == CALL_INSN
&& caller_save_spill_class != NO_REGS)
{
int j;
/* See if this register would conflict with any reload that
needs a group or any reload that needs a nongroup. */
int nongroup_need = 0;
int *caller_save_needs;
for (j = 0; j < n_reloads; j++)
if (reg_classes_intersect_p (caller_save_spill_class,
reload_reg_class[j])
&& ((CLASS_MAX_NREGS
(reload_reg_class[j],
(GET_MODE_SIZE (reload_outmode[j])
> GET_MODE_SIZE (reload_inmode[j]))
? reload_outmode[j] : reload_inmode[j])
> 1)
|| reload_nongroup[j]))
{
nongroup_need = 1;
break;
}
caller_save_needs
= (caller_save_group_size > 1
? insn_needs.other.groups
: insn_needs.other.regs[nongroup_need]);
if (caller_save_needs[(int) caller_save_spill_class] == 0)
{
register enum reg_class *p
= reg_class_superclasses[(int) caller_save_spill_class];
caller_save_needs[(int) caller_save_spill_class]++;
while (*p != LIM_REG_CLASSES)
caller_save_needs[(int) *p++] += 1;
}
/* Show that this basic block will need a register of
this class. */
if (global
&& ! (basic_block_needs[(int) caller_save_spill_class]
[this_block]))
{
basic_block_needs[(int) caller_save_spill_class]
[this_block] = 1;
something_changed = 1;
}
}
/* If this insn stores the value of a function call,
and that value is in a register that has been spilled,
and if the insn needs a reload in a class
that might use that register as the reload register,
then add an extra need in that class.
This makes sure we have a register available that does
not overlap the return value. */
if (SMALL_REGISTER_CLASSES && avoid_return_reg)
{
int regno = REGNO (avoid_return_reg);
int nregs
= HARD_REGNO_NREGS (regno, GET_MODE (avoid_return_reg));
int r;
int basic_needs[N_REG_CLASSES], basic_groups[N_REG_CLASSES];
/* First compute the "basic needs", which counts a
need only in the smallest class in which it
is required. */
bcopy ((char *) insn_needs.other.regs[0],
(char *) basic_needs, sizeof basic_needs);
bcopy ((char *) insn_needs.other.groups,
(char *) basic_groups, sizeof basic_groups);
for (i = 0; i < N_REG_CLASSES; i++)
{
enum reg_class *p;
if (basic_needs[i] >= 0)
for (p = reg_class_superclasses[i];
*p != LIM_REG_CLASSES; p++)
basic_needs[(int) *p] -= basic_needs[i];
if (basic_groups[i] >= 0)
for (p = reg_class_superclasses[i];
*p != LIM_REG_CLASSES; p++)
basic_groups[(int) *p] -= basic_groups[i];
}
/* Now count extra regs if there might be a conflict with
the return value register. */
for (r = regno; r < regno + nregs; r++)
if (spill_reg_order[r] >= 0)
for (i = 0; i < N_REG_CLASSES; i++)
if (TEST_HARD_REG_BIT (reg_class_contents[i], r))
{
if (basic_needs[i] > 0)
{
enum reg_class *p;
insn_needs.other.regs[0][i]++;
p = reg_class_superclasses[i];
while (*p != LIM_REG_CLASSES)
insn_needs.other.regs[0][(int) *p++]++;
}
if (basic_groups[i] > 0)
{
enum reg_class *p;
insn_needs.other.groups[i]++;
p = reg_class_superclasses[i];
while (*p != LIM_REG_CLASSES)
insn_needs.other.groups[(int) *p++]++;
}
}
}
/* For each class, collect maximum need of any insn. */
for (i = 0; i < N_REG_CLASSES; i++)
{
if (max_needs[i] < insn_needs.other.regs[0][i])
{
max_needs[i] = insn_needs.other.regs[0][i];
max_needs_insn[i] = insn;
}
if (max_groups[i] < insn_needs.other.groups[i])
{
max_groups[i] = insn_needs.other.groups[i];
max_groups_insn[i] = insn;
}
if (max_nongroups[i] < insn_needs.other.regs[1][i])
{
max_nongroups[i] = insn_needs.other.regs[1][i];
max_nongroups_insn[i] = insn;
}
}
return something_changed;
}
/* Find a group of exactly 2 registers.
First try to fill out the group by spilling a single register which
would allow completion of the group.
Then try to create a new group from a pair of registers, neither of
which are explicitly used.
Then try to create a group from any pair of registers. */
static int
find_tworeg_group (global, class, dumpfile)
int global;
int class;
FILE *dumpfile;
{
int i;
/* First, look for a register that will complete a group. */
for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
{
int j, other;
j = potential_reload_regs[i];
if (j >= 0 && ! TEST_HARD_REG_BIT (bad_spill_regs, j)
&& ((j > 0 && (other = j - 1, spill_reg_order[other] >= 0)
&& TEST_HARD_REG_BIT (reg_class_contents[class], j)
&& TEST_HARD_REG_BIT (reg_class_contents[class], other)
&& HARD_REGNO_MODE_OK (other, group_mode[class])
&& ! TEST_HARD_REG_BIT (counted_for_nongroups, other)
/* We don't want one part of another group.
We could get "two groups" that overlap! */
&& ! TEST_HARD_REG_BIT (counted_for_groups, other))
|| (j < FIRST_PSEUDO_REGISTER - 1
&& (other = j + 1, spill_reg_order[other] >= 0)
&& TEST_HARD_REG_BIT (reg_class_contents[class], j)
&& TEST_HARD_REG_BIT (reg_class_contents[class], other)
&& HARD_REGNO_MODE_OK (j, group_mode[class])
&& ! TEST_HARD_REG_BIT (counted_for_nongroups, other)
&& ! TEST_HARD_REG_BIT (counted_for_groups, other))))
{
register enum reg_class *p;
/* We have found one that will complete a group,
so count off one group as provided. */
max_groups[class]--;
p = reg_class_superclasses[class];
while (*p != LIM_REG_CLASSES)
{
if (group_size [(int) *p] <= group_size [class])
max_groups[(int) *p]--;
p++;
}
/* Indicate both these regs are part of a group. */
SET_HARD_REG_BIT (counted_for_groups, j);
SET_HARD_REG_BIT (counted_for_groups, other);
break;
}
}
/* We can't complete a group, so start one. */
/* Look for a pair neither of which is explicitly used. */
if (SMALL_REGISTER_CLASSES && i == FIRST_PSEUDO_REGISTER)
for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
{
int j, k;
j = potential_reload_regs[i];
/* Verify that J+1 is a potential reload reg. */
for (k = 0; k < FIRST_PSEUDO_REGISTER; k++)
if (potential_reload_regs[k] == j + 1)
break;
if (j >= 0 && j + 1 < FIRST_PSEUDO_REGISTER
&& k < FIRST_PSEUDO_REGISTER
&& spill_reg_order[j] < 0 && spill_reg_order[j + 1] < 0
&& TEST_HARD_REG_BIT (reg_class_contents[class], j)
&& TEST_HARD_REG_BIT (reg_class_contents[class], j + 1)
&& HARD_REGNO_MODE_OK (j, group_mode[class])
&& ! TEST_HARD_REG_BIT (counted_for_nongroups,
j + 1)
&& ! TEST_HARD_REG_BIT (bad_spill_regs, j + 1)
/* Reject J at this stage
if J+1 was explicitly used. */
&& ! regs_explicitly_used[j + 1])
break;
}
/* Now try any group at all
whose registers are not in bad_spill_regs. */
if (i == FIRST_PSEUDO_REGISTER)
for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
{
int j, k;
j = potential_reload_regs[i];
/* Verify that J+1 is a potential reload reg. */
for (k = 0; k < FIRST_PSEUDO_REGISTER; k++)
if (potential_reload_regs[k] == j + 1)
break;
if (j >= 0 && j + 1 < FIRST_PSEUDO_REGISTER
&& k < FIRST_PSEUDO_REGISTER
&& spill_reg_order[j] < 0 && spill_reg_order[j + 1] < 0
&& TEST_HARD_REG_BIT (reg_class_contents[class], j)
&& TEST_HARD_REG_BIT (reg_class_contents[class], j + 1)
&& HARD_REGNO_MODE_OK (j, group_mode[class])
&& ! TEST_HARD_REG_BIT (counted_for_nongroups, j + 1)
&& ! TEST_HARD_REG_BIT (bad_spill_regs, j + 1))
break;
}
/* I should be the index in potential_reload_regs
of the new reload reg we have found. */
if (i < FIRST_PSEUDO_REGISTER)
return new_spill_reg (i, class, max_needs, NULL_PTR,
global, dumpfile);
/* There are no groups left to spill. */
spill_failure (max_groups_insn[class]);
failure = 1;
return 1;
}
/* Find a group of more than 2 registers.
Look for a sufficient sequence of unspilled registers, and spill them all
at once. */
static int
find_group (global, class, dumpfile)
int global;
int class;
FILE *dumpfile;
{
int something_changed = 0;
int i;
for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
{
int j, k;
j = potential_reload_regs[i];
if (j >= 0
&& j + group_size[class] <= FIRST_PSEUDO_REGISTER
&& HARD_REGNO_MODE_OK (j, group_mode[class]))
{
/* Check each reg in the sequence. */
for (k = 0; k < group_size[class]; k++)
if (! (spill_reg_order[j + k] < 0
&& ! TEST_HARD_REG_BIT (bad_spill_regs, j + k)
&& TEST_HARD_REG_BIT (reg_class_contents[class], j + k)))
break;
/* We got a full sequence, so spill them all. */
if (k == group_size[class])
{
register enum reg_class *p;
for (k = 0; k < group_size[class]; k++)
{
int idx;
SET_HARD_REG_BIT (counted_for_groups, j + k);
for (idx = 0; idx < FIRST_PSEUDO_REGISTER; idx++)
if (potential_reload_regs[idx] == j + k)
break;
something_changed |= new_spill_reg (idx, class, max_needs,
NULL_PTR, global,
dumpfile);
}
/* We have found one that will complete a group,
so count off one group as provided. */
max_groups[class]--;
p = reg_class_superclasses[class];
while (*p != LIM_REG_CLASSES)
{
if (group_size [(int) *p]
<= group_size [class])
max_groups[(int) *p]--;
p++;
}
return something_changed;
}
}
}
/* There are no groups left. */
spill_failure (max_groups_insn[class]);
failure = 1;
return 1;
}
/* Find more reload regs to satisfy the remaining need.
Do it by ascending class number, since otherwise a reg
might be spilled for a big class and might fail to count
for a smaller class even though it belongs to that class.
Count spilled regs in `spills', and add entries to
`spill_regs' and `spill_reg_order'.
??? Note there is a problem here.
When there is a need for a group in a high-numbered class,
and also need for non-group regs that come from a lower class,
the non-group regs are chosen first. If there aren't many regs,
they might leave no room for a group.
This was happening on the 386. To fix it, we added the code
that calls possible_group_p, so that the lower class won't
break up the last possible group.
Really fixing the problem would require changes above
in counting the regs already spilled, and in choose_reload_regs.
It might be hard to avoid introducing bugs there. */
static int
find_reload_regs (global, dumpfile)
int global;
FILE *dumpfile;
{
int class;
int something_changed = 0;
CLEAR_HARD_REG_SET (counted_for_groups);
CLEAR_HARD_REG_SET (counted_for_nongroups);
for (class = 0; class < N_REG_CLASSES; class++)
{
/* First get the groups of registers.
If we got single registers first, we might fragment
possible groups. */
while (max_groups[class] > 0)
{
/* If any single spilled regs happen to form groups,
count them now. Maybe we don't really need
to spill another group. */
count_possible_groups (group_size, group_mode, max_groups, class);
if (max_groups[class] <= 0)
break;
/* Groups of size 2 (the only groups used on most machines)
are treated specially. */
if (group_size[class] == 2)
something_changed |= find_tworeg_group (global, class, dumpfile);
else
something_changed |= find_group (global, class, dumpfile);
if (failure)
return 1;
}
/* Now similarly satisfy all need for single registers. */
while (max_needs[class] > 0 || max_nongroups[class] > 0)
{
int i;
/* If we spilled enough regs, but they weren't counted
against the non-group need, see if we can count them now.
If so, we can avoid some actual spilling. */
if (max_needs[class] <= 0 && max_nongroups[class] > 0)
for (i = 0; i < n_spills; i++)
{
int regno = spill_regs[i];
if (TEST_HARD_REG_BIT (reg_class_contents[class], regno)
&& !TEST_HARD_REG_BIT (counted_for_groups, regno)
&& !TEST_HARD_REG_BIT (counted_for_nongroups, regno)
&& max_nongroups[class] > 0)
{
register enum reg_class *p;
SET_HARD_REG_BIT (counted_for_nongroups, regno);
max_nongroups[class]--;
p = reg_class_superclasses[class];
while (*p != LIM_REG_CLASSES)
max_nongroups[(int) *p++]--;
}
}
if (max_needs[class] <= 0 && max_nongroups[class] <= 0)
break;
/* Consider the potential reload regs that aren't
yet in use as reload regs, in order of preference.
Find the most preferred one that's in this class. */
for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
{
int regno = potential_reload_regs[i];
if (regno >= 0
&& TEST_HARD_REG_BIT (reg_class_contents[class], regno)
/* If this reg will not be available for groups,
pick one that does not foreclose possible groups.
This is a kludge, and not very general,
but it should be sufficient to make the 386 work,
and the problem should not occur on machines with
more registers. */
&& (max_nongroups[class] == 0
|| possible_group_p (regno, max_groups)))
break;
}
/* If we couldn't get a register, try to get one even if we
might foreclose possible groups. This may cause problems
later, but that's better than aborting now, since it is
possible that we will, in fact, be able to form the needed
group even with this allocation. */
if (i >= FIRST_PSEUDO_REGISTER
&& (asm_noperands (max_needs[class] > 0
? max_needs_insn[class]
: max_nongroups_insn[class])
< 0))
for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
if (potential_reload_regs[i] >= 0
&& TEST_HARD_REG_BIT (reg_class_contents[class],
potential_reload_regs[i]))
break;
/* I should be the index in potential_reload_regs
of the new reload reg we have found. */
if (i >= FIRST_PSEUDO_REGISTER)
{
/* There are no possible registers left to spill. */
spill_failure (max_needs[class] > 0 ? max_needs_insn[class]
: max_nongroups_insn[class]);
failure = 1;
return 1;
}
else
something_changed |= new_spill_reg (i, class, max_needs,
max_nongroups, global,
dumpfile);
}
}
return something_changed;
}
/* Nonzero if, after spilling reg REGNO for non-groups, /* Nonzero if, after spilling reg REGNO for non-groups,
it will still be possible to find a group if we still need one. */ it will still be possible to find a group if we still need one. */
......
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