blob: 2af7fdb6d1d23ec12d7488675dea486c2ba8437f [file] [log] [blame]
/* Convert tree expression to rtl instructions, for GNU compiler.
Copyright (C) 1988, 92-97, 1998 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 <stdio.h>
#include "machmode.h"
#include "rtl.h"
#include "tree.h"
#include "obstack.h"
#include "flags.h"
#include "regs.h"
#include "hard-reg-set.h"
#include "except.h"
#include "function.h"
#include "insn-flags.h"
#include "insn-codes.h"
#include "expr.h"
#include "insn-config.h"
#include "recog.h"
#include "output.h"
#include "typeclass.h"
#include "defaults.h"
#include "bytecode.h"
#include "bc-opcode.h"
#include "bc-typecd.h"
#include "bc-optab.h"
#include "bc-emit.h"
#define CEIL(x,y) (((x) + (y) - 1) / (y))
/* Decide whether a function's arguments should be processed
from first to last or from last to first.
They should if the stack and args grow in opposite directions, but
only if we have push insns. */
#ifdef PUSH_ROUNDING
#if defined (STACK_GROWS_DOWNWARD) != defined (ARGS_GROW_DOWNWARD)
#define PUSH_ARGS_REVERSED /* If it's last to first */
#endif
#endif
#ifndef STACK_PUSH_CODE
#ifdef STACK_GROWS_DOWNWARD
#define STACK_PUSH_CODE PRE_DEC
#else
#define STACK_PUSH_CODE PRE_INC
#endif
#endif
/* Like STACK_BOUNDARY but in units of bytes, not bits. */
#define STACK_BYTES (STACK_BOUNDARY / BITS_PER_UNIT)
/* If this is nonzero, we do not bother generating VOLATILE
around volatile memory references, and we are willing to
output indirect addresses. If cse is to follow, we reject
indirect addresses so a useful potential cse is generated;
if it is used only once, instruction combination will produce
the same indirect address eventually. */
int cse_not_expected;
/* Nonzero to generate code for all the subroutines within an
expression before generating the upper levels of the expression.
Nowadays this is never zero. */
int do_preexpand_calls = 1;
/* Number of units that we should eventually pop off the stack.
These are the arguments to function calls that have already returned. */
int pending_stack_adjust;
/* Nonzero means stack pops must not be deferred, and deferred stack
pops must not be output. It is nonzero inside a function call,
inside a conditional expression, inside a statement expression,
and in other cases as well. */
int inhibit_defer_pop;
/* When temporaries are created by TARGET_EXPRs, they are created at
this level of temp_slot_level, so that they can remain allocated
until no longer needed. CLEANUP_POINT_EXPRs define the lifetime
of TARGET_EXPRs. */
int target_temp_slot_level;
/* Nonzero means __builtin_saveregs has already been done in this function.
The value is the pseudoreg containing the value __builtin_saveregs
returned. */
static rtx saveregs_value;
/* Similarly for __builtin_apply_args. */
static rtx apply_args_value;
/* Don't check memory usage, since code is being emitted to check a memory
usage. Used when flag_check_memory_usage is true, to avoid infinite
recursion. */
static int in_check_memory_usage;
/* This structure is used by move_by_pieces to describe the move to
be performed. */
struct move_by_pieces
{
rtx to;
rtx to_addr;
int autinc_to;
int explicit_inc_to;
int to_struct;
rtx from;
rtx from_addr;
int autinc_from;
int explicit_inc_from;
int from_struct;
int len;
int offset;
int reverse;
};
/* This structure is used by clear_by_pieces to describe the clear to
be performed. */
struct clear_by_pieces
{
rtx to;
rtx to_addr;
int autinc_to;
int explicit_inc_to;
int to_struct;
int len;
int offset;
int reverse;
};
/* Used to generate bytecodes: keep track of size of local variables,
as well as depth of arithmetic stack. (Notice that variables are
stored on the machine's stack, not the arithmetic stack.) */
static rtx get_push_address PROTO ((int));
extern int local_vars_size;
extern int stack_depth;
extern int max_stack_depth;
extern struct obstack permanent_obstack;
extern rtx arg_pointer_save_area;
static rtx enqueue_insn PROTO((rtx, rtx));
static int queued_subexp_p PROTO((rtx));
static void init_queue PROTO((void));
static void move_by_pieces PROTO((rtx, rtx, int, int));
static int move_by_pieces_ninsns PROTO((unsigned int, int));
static void move_by_pieces_1 PROTO((rtx (*) (), enum machine_mode,
struct move_by_pieces *));
static void clear_by_pieces PROTO((rtx, int, int));
static void clear_by_pieces_1 PROTO((rtx (*) (), enum machine_mode,
struct clear_by_pieces *));
static int is_zeros_p PROTO((tree));
static int mostly_zeros_p PROTO((tree));
static void store_constructor PROTO((tree, rtx, int));
static rtx store_field PROTO((rtx, int, int, enum machine_mode, tree,
enum machine_mode, int, int, int));
static tree save_noncopied_parts PROTO((tree, tree));
static tree init_noncopied_parts PROTO((tree, tree));
static int safe_from_p PROTO((rtx, tree));
static int fixed_type_p PROTO((tree));
static rtx var_rtx PROTO((tree));
static int get_pointer_alignment PROTO((tree, unsigned));
static tree string_constant PROTO((tree, tree *));
static tree c_strlen PROTO((tree));
static rtx expand_builtin PROTO((tree, rtx, rtx,
enum machine_mode, int));
static int apply_args_size PROTO((void));
static int apply_result_size PROTO((void));
static rtx result_vector PROTO((int, rtx));
static rtx expand_builtin_apply_args PROTO((void));
static rtx expand_builtin_apply PROTO((rtx, rtx, rtx));
static void expand_builtin_return PROTO((rtx));
static rtx expand_increment PROTO((tree, int, int));
void bc_expand_increment PROTO((struct increment_operator *, tree));
rtx bc_allocate_local PROTO((int, int));
void bc_store_memory PROTO((tree, tree));
tree bc_expand_component_address PROTO((tree));
tree bc_expand_address PROTO((tree));
void bc_expand_constructor PROTO((tree));
void bc_adjust_stack PROTO((int));
tree bc_canonicalize_array_ref PROTO((tree));
void bc_load_memory PROTO((tree, tree));
void bc_load_externaddr PROTO((rtx));
void bc_load_externaddr_id PROTO((tree, int));
void bc_load_localaddr PROTO((rtx));
void bc_load_parmaddr PROTO((rtx));
static void preexpand_calls PROTO((tree));
static void do_jump_by_parts_greater PROTO((tree, int, rtx, rtx));
void do_jump_by_parts_greater_rtx PROTO((enum machine_mode, int, rtx, rtx, rtx, rtx));
static void do_jump_by_parts_equality PROTO((tree, rtx, rtx));
static void do_jump_by_parts_equality_rtx PROTO((rtx, rtx, rtx));
static void do_jump_for_compare PROTO((rtx, rtx, rtx));
static rtx compare PROTO((tree, enum rtx_code, enum rtx_code));
static rtx do_store_flag PROTO((tree, rtx, enum machine_mode, int));
extern tree truthvalue_conversion PROTO((tree));
/* Record for each mode whether we can move a register directly to or
from an object of that mode in memory. If we can't, we won't try
to use that mode directly when accessing a field of that mode. */
static char direct_load[NUM_MACHINE_MODES];
static char direct_store[NUM_MACHINE_MODES];
/* MOVE_RATIO is the number of move instructions that is better than
a block move. */
#ifndef MOVE_RATIO
#if defined (HAVE_movstrqi) || defined (HAVE_movstrhi) || defined (HAVE_movstrsi) || defined (HAVE_movstrdi) || defined (HAVE_movstrti)
#define MOVE_RATIO 2
#else
/* A value of around 6 would minimize code size; infinity would minimize
execution time. */
#define MOVE_RATIO 15
#endif
#endif
/* This array records the insn_code of insns to perform block moves. */
enum insn_code movstr_optab[NUM_MACHINE_MODES];
/* This array records the insn_code of insns to perform block clears. */
enum insn_code clrstr_optab[NUM_MACHINE_MODES];
/* SLOW_UNALIGNED_ACCESS is non-zero if unaligned accesses are very slow. */
#ifndef SLOW_UNALIGNED_ACCESS
#define SLOW_UNALIGNED_ACCESS STRICT_ALIGNMENT
#endif
/* Register mappings for target machines without register windows. */
#ifndef INCOMING_REGNO
#define INCOMING_REGNO(OUT) (OUT)
#endif
#ifndef OUTGOING_REGNO
#define OUTGOING_REGNO(IN) (IN)
#endif
/* Maps used to convert modes to const, load, and store bytecodes. */
enum bytecode_opcode mode_to_const_map[MAX_MACHINE_MODE];
enum bytecode_opcode mode_to_load_map[MAX_MACHINE_MODE];
enum bytecode_opcode mode_to_store_map[MAX_MACHINE_MODE];
/* Initialize maps used to convert modes to const, load, and store
bytecodes. */
void
bc_init_mode_to_opcode_maps ()
{
int mode;
for (mode = 0; mode < (int) MAX_MACHINE_MODE; mode++)
mode_to_const_map[mode]
= mode_to_load_map[mode]
= mode_to_store_map[mode] = neverneverland;
#define DEF_MODEMAP(SYM, CODE, UCODE, CONST, LOAD, STORE) \
mode_to_const_map[(int) SYM] = CONST; \
mode_to_load_map[(int) SYM] = LOAD; \
mode_to_store_map[(int) SYM] = STORE;
#include "modemap.def"
#undef DEF_MODEMAP
}
/* This is run once per compilation to set up which modes can be used
directly in memory and to initialize the block move optab. */
void
init_expr_once ()
{
rtx insn, pat;
enum machine_mode mode;
/* Try indexing by frame ptr and try by stack ptr.
It is known that on the Convex the stack ptr isn't a valid index.
With luck, one or the other is valid on any machine. */
rtx mem = gen_rtx (MEM, VOIDmode, stack_pointer_rtx);
rtx mem1 = gen_rtx (MEM, VOIDmode, frame_pointer_rtx);
start_sequence ();
insn = emit_insn (gen_rtx (SET, 0, NULL_RTX, NULL_RTX));
pat = PATTERN (insn);
for (mode = VOIDmode; (int) mode < NUM_MACHINE_MODES;
mode = (enum machine_mode) ((int) mode + 1))
{
int regno;
rtx reg;
int num_clobbers;
direct_load[(int) mode] = direct_store[(int) mode] = 0;
PUT_MODE (mem, mode);
PUT_MODE (mem1, mode);
/* See if there is some register that can be used in this mode and
directly loaded or stored from memory. */
if (mode != VOIDmode && mode != BLKmode)
for (regno = 0; regno < FIRST_PSEUDO_REGISTER
&& (direct_load[(int) mode] == 0 || direct_store[(int) mode] == 0);
regno++)
{
if (! HARD_REGNO_MODE_OK (regno, mode))
continue;
reg = gen_rtx (REG, mode, regno);
SET_SRC (pat) = mem;
SET_DEST (pat) = reg;
if (recog (pat, insn, &num_clobbers) >= 0)
direct_load[(int) mode] = 1;
SET_SRC (pat) = mem1;
SET_DEST (pat) = reg;
if (recog (pat, insn, &num_clobbers) >= 0)
direct_load[(int) mode] = 1;
SET_SRC (pat) = reg;
SET_DEST (pat) = mem;
if (recog (pat, insn, &num_clobbers) >= 0)
direct_store[(int) mode] = 1;
SET_SRC (pat) = reg;
SET_DEST (pat) = mem1;
if (recog (pat, insn, &num_clobbers) >= 0)
direct_store[(int) mode] = 1;
}
}
end_sequence ();
}
/* This is run at the start of compiling a function. */
void
init_expr ()
{
init_queue ();
pending_stack_adjust = 0;
inhibit_defer_pop = 0;
saveregs_value = 0;
apply_args_value = 0;
forced_labels = 0;
}
/* Save all variables describing the current status into the structure *P.
This is used before starting a nested function. */
void
save_expr_status (p)
struct function *p;
{
/* Instead of saving the postincrement queue, empty it. */
emit_queue ();
p->pending_stack_adjust = pending_stack_adjust;
p->inhibit_defer_pop = inhibit_defer_pop;
p->saveregs_value = saveregs_value;
p->apply_args_value = apply_args_value;
p->forced_labels = forced_labels;
pending_stack_adjust = 0;
inhibit_defer_pop = 0;
saveregs_value = 0;
apply_args_value = 0;
forced_labels = 0;
}
/* Restore all variables describing the current status from the structure *P.
This is used after a nested function. */
void
restore_expr_status (p)
struct function *p;
{
pending_stack_adjust = p->pending_stack_adjust;
inhibit_defer_pop = p->inhibit_defer_pop;
saveregs_value = p->saveregs_value;
apply_args_value = p->apply_args_value;
forced_labels = p->forced_labels;
}
/* Manage the queue of increment instructions to be output
for POSTINCREMENT_EXPR expressions, etc. */
static rtx pending_chain;
/* Queue up to increment (or change) VAR later. BODY says how:
BODY should be the same thing you would pass to emit_insn
to increment right away. It will go to emit_insn later on.
The value is a QUEUED expression to be used in place of VAR
where you want to guarantee the pre-incrementation value of VAR. */
static rtx
enqueue_insn (var, body)
rtx var, body;
{
pending_chain = gen_rtx (QUEUED, GET_MODE (var),
var, NULL_RTX, NULL_RTX, body, pending_chain);
return pending_chain;
}
/* Use protect_from_queue to convert a QUEUED expression
into something that you can put immediately into an instruction.
If the queued incrementation has not happened yet,
protect_from_queue returns the variable itself.
If the incrementation has happened, protect_from_queue returns a temp
that contains a copy of the old value of the variable.
Any time an rtx which might possibly be a QUEUED is to be put
into an instruction, it must be passed through protect_from_queue first.
QUEUED expressions are not meaningful in instructions.
Do not pass a value through protect_from_queue and then hold
on to it for a while before putting it in an instruction!
If the queue is flushed in between, incorrect code will result. */
rtx
protect_from_queue (x, modify)
register rtx x;
int modify;
{
register RTX_CODE code = GET_CODE (x);
#if 0 /* A QUEUED can hang around after the queue is forced out. */
/* Shortcut for most common case. */
if (pending_chain == 0)
return x;
#endif
if (code != QUEUED)
{
/* A special hack for read access to (MEM (QUEUED ...)) to facilitate
use of autoincrement. Make a copy of the contents of the memory
location rather than a copy of the address, but not if the value is
of mode BLKmode. Don't modify X in place since it might be
shared. */
if (code == MEM && GET_MODE (x) != BLKmode
&& GET_CODE (XEXP (x, 0)) == QUEUED && !modify)
{
register rtx y = XEXP (x, 0);
register rtx new = gen_rtx (MEM, GET_MODE (x), QUEUED_VAR (y));
MEM_IN_STRUCT_P (new) = MEM_IN_STRUCT_P (x);
RTX_UNCHANGING_P (new) = RTX_UNCHANGING_P (x);
MEM_VOLATILE_P (new) = MEM_VOLATILE_P (x);
if (QUEUED_INSN (y))
{
register rtx temp = gen_reg_rtx (GET_MODE (new));
emit_insn_before (gen_move_insn (temp, new),
QUEUED_INSN (y));
return temp;
}
return new;
}
/* Otherwise, recursively protect the subexpressions of all
the kinds of rtx's that can contain a QUEUED. */
if (code == MEM)
{
rtx tem = protect_from_queue (XEXP (x, 0), 0);
if (tem != XEXP (x, 0))
{
x = copy_rtx (x);
XEXP (x, 0) = tem;
}
}
else if (code == PLUS || code == MULT)
{
rtx new0 = protect_from_queue (XEXP (x, 0), 0);
rtx new1 = protect_from_queue (XEXP (x, 1), 0);
if (new0 != XEXP (x, 0) || new1 != XEXP (x, 1))
{
x = copy_rtx (x);
XEXP (x, 0) = new0;
XEXP (x, 1) = new1;
}
}
return x;
}
/* If the increment has not happened, use the variable itself. */
if (QUEUED_INSN (x) == 0)
return QUEUED_VAR (x);
/* If the increment has happened and a pre-increment copy exists,
use that copy. */
if (QUEUED_COPY (x) != 0)
return QUEUED_COPY (x);
/* The increment has happened but we haven't set up a pre-increment copy.
Set one up now, and use it. */
QUEUED_COPY (x) = gen_reg_rtx (GET_MODE (QUEUED_VAR (x)));
emit_insn_before (gen_move_insn (QUEUED_COPY (x), QUEUED_VAR (x)),
QUEUED_INSN (x));
return QUEUED_COPY (x);
}
/* Return nonzero if X contains a QUEUED expression:
if it contains anything that will be altered by a queued increment.
We handle only combinations of MEM, PLUS, MINUS and MULT operators
since memory addresses generally contain only those. */
static int
queued_subexp_p (x)
rtx x;
{
register enum rtx_code code = GET_CODE (x);
switch (code)
{
case QUEUED:
return 1;
case MEM:
return queued_subexp_p (XEXP (x, 0));
case MULT:
case PLUS:
case MINUS:
return (queued_subexp_p (XEXP (x, 0))
|| queued_subexp_p (XEXP (x, 1)));
default:
return 0;
}
}
/* Perform all the pending incrementations. */
void
emit_queue ()
{
register rtx p;
while (p = pending_chain)
{
QUEUED_INSN (p) = emit_insn (QUEUED_BODY (p));
pending_chain = QUEUED_NEXT (p);
}
}
static void
init_queue ()
{
if (pending_chain)
abort ();
}
/* Copy data from FROM to TO, where the machine modes are not the same.
Both modes may be integer, or both may be floating.
UNSIGNEDP should be nonzero if FROM is an unsigned type.
This causes zero-extension instead of sign-extension. */
void
convert_move (to, from, unsignedp)
register rtx to, from;
int unsignedp;
{
enum machine_mode to_mode = GET_MODE (to);
enum machine_mode from_mode = GET_MODE (from);
int to_real = GET_MODE_CLASS (to_mode) == MODE_FLOAT;
int from_real = GET_MODE_CLASS (from_mode) == MODE_FLOAT;
enum insn_code code;
rtx libcall;
/* rtx code for making an equivalent value. */
enum rtx_code equiv_code = (unsignedp ? ZERO_EXTEND : SIGN_EXTEND);
to = protect_from_queue (to, 1);
from = protect_from_queue (from, 0);
if (to_real != from_real)
abort ();
/* If FROM is a SUBREG that indicates that we have already done at least
the required extension, strip it. We don't handle such SUBREGs as
TO here. */
if (GET_CODE (from) == SUBREG && SUBREG_PROMOTED_VAR_P (from)
&& (GET_MODE_SIZE (GET_MODE (SUBREG_REG (from)))
>= GET_MODE_SIZE (to_mode))
&& SUBREG_PROMOTED_UNSIGNED_P (from) == unsignedp)
from = gen_lowpart (to_mode, from), from_mode = to_mode;
if (GET_CODE (to) == SUBREG && SUBREG_PROMOTED_VAR_P (to))
abort ();
if (to_mode == from_mode
|| (from_mode == VOIDmode && CONSTANT_P (from)))
{
emit_move_insn (to, from);
return;
}
if (to_real)
{
rtx value;
if (GET_MODE_BITSIZE (from_mode) < GET_MODE_BITSIZE (to_mode))
{
/* Try converting directly if the insn is supported. */
if ((code = can_extend_p (to_mode, from_mode, 0))
!= CODE_FOR_nothing)
{
emit_unop_insn (code, to, from, UNKNOWN);
return;
}
}
#ifdef HAVE_trunchfqf2
if (HAVE_trunchfqf2 && from_mode == HFmode && to_mode == QFmode)
{
emit_unop_insn (CODE_FOR_trunchfqf2, to, from, UNKNOWN);
return;
}
#endif
#ifdef HAVE_trunctqfqf2
if (HAVE_trunctqfqf2 && from_mode == TQFmode && to_mode == QFmode)
{
emit_unop_insn (CODE_FOR_trunctqfqf2, to, from, UNKNOWN);
return;
}
#endif
#ifdef HAVE_truncsfqf2
if (HAVE_truncsfqf2 && from_mode == SFmode && to_mode == QFmode)
{
emit_unop_insn (CODE_FOR_truncsfqf2, to, from, UNKNOWN);
return;
}
#endif
#ifdef HAVE_truncdfqf2
if (HAVE_truncdfqf2 && from_mode == DFmode && to_mode == QFmode)
{
emit_unop_insn (CODE_FOR_truncdfqf2, to, from, UNKNOWN);
return;
}
#endif
#ifdef HAVE_truncxfqf2
if (HAVE_truncxfqf2 && from_mode == XFmode && to_mode == QFmode)
{
emit_unop_insn (CODE_FOR_truncxfqf2, to, from, UNKNOWN);
return;
}
#endif
#ifdef HAVE_trunctfqf2
if (HAVE_trunctfqf2 && from_mode == TFmode && to_mode == QFmode)
{
emit_unop_insn (CODE_FOR_trunctfqf2, to, from, UNKNOWN);
return;
}
#endif
#ifdef HAVE_trunctqfhf2
if (HAVE_trunctqfhf2 && from_mode == TQFmode && to_mode == HFmode)
{
emit_unop_insn (CODE_FOR_trunctqfhf2, to, from, UNKNOWN);
return;
}
#endif
#ifdef HAVE_truncsfhf2
if (HAVE_truncsfhf2 && from_mode == SFmode && to_mode == HFmode)
{
emit_unop_insn (CODE_FOR_truncsfhf2, to, from, UNKNOWN);
return;
}
#endif
#ifdef HAVE_truncdfhf2
if (HAVE_truncdfhf2 && from_mode == DFmode && to_mode == HFmode)
{
emit_unop_insn (CODE_FOR_truncdfhf2, to, from, UNKNOWN);
return;
}
#endif
#ifdef HAVE_truncxfhf2
if (HAVE_truncxfhf2 && from_mode == XFmode && to_mode == HFmode)
{
emit_unop_insn (CODE_FOR_truncxfhf2, to, from, UNKNOWN);
return;
}
#endif
#ifdef HAVE_trunctfhf2
if (HAVE_trunctfhf2 && from_mode == TFmode && to_mode == HFmode)
{
emit_unop_insn (CODE_FOR_trunctfhf2, to, from, UNKNOWN);
return;
}
#endif
#ifdef HAVE_truncsftqf2
if (HAVE_truncsftqf2 && from_mode == SFmode && to_mode == TQFmode)
{
emit_unop_insn (CODE_FOR_truncsftqf2, to, from, UNKNOWN);
return;
}
#endif
#ifdef HAVE_truncdftqf2
if (HAVE_truncdftqf2 && from_mode == DFmode && to_mode == TQFmode)
{
emit_unop_insn (CODE_FOR_truncdftqf2, to, from, UNKNOWN);
return;
}
#endif
#ifdef HAVE_truncxftqf2
if (HAVE_truncxftqf2 && from_mode == XFmode && to_mode == TQFmode)
{
emit_unop_insn (CODE_FOR_truncxftqf2, to, from, UNKNOWN);
return;
}
#endif
#ifdef HAVE_trunctftqf2
if (HAVE_trunctftqf2 && from_mode == TFmode && to_mode == TQFmode)
{
emit_unop_insn (CODE_FOR_trunctftqf2, to, from, UNKNOWN);
return;
}
#endif
#ifdef HAVE_truncdfsf2
if (HAVE_truncdfsf2 && from_mode == DFmode && to_mode == SFmode)
{
emit_unop_insn (CODE_FOR_truncdfsf2, to, from, UNKNOWN);
return;
}
#endif
#ifdef HAVE_truncxfsf2
if (HAVE_truncxfsf2 && from_mode == XFmode && to_mode == SFmode)
{
emit_unop_insn (CODE_FOR_truncxfsf2, to, from, UNKNOWN);
return;
}
#endif
#ifdef HAVE_trunctfsf2
if (HAVE_trunctfsf2 && from_mode == TFmode && to_mode == SFmode)
{
emit_unop_insn (CODE_FOR_trunctfsf2, to, from, UNKNOWN);
return;
}
#endif
#ifdef HAVE_truncxfdf2
if (HAVE_truncxfdf2 && from_mode == XFmode && to_mode == DFmode)
{
emit_unop_insn (CODE_FOR_truncxfdf2, to, from, UNKNOWN);
return;
}
#endif
#ifdef HAVE_trunctfdf2
if (HAVE_trunctfdf2 && from_mode == TFmode && to_mode == DFmode)
{
emit_unop_insn (CODE_FOR_trunctfdf2, to, from, UNKNOWN);
return;
}
#endif
libcall = (rtx) 0;
switch (from_mode)
{
case SFmode:
switch (to_mode)
{
case DFmode:
libcall = extendsfdf2_libfunc;
break;
case XFmode:
libcall = extendsfxf2_libfunc;
break;
case TFmode:
libcall = extendsftf2_libfunc;
break;
default:
break;
}
break;
case DFmode:
switch (to_mode)
{
case SFmode:
libcall = truncdfsf2_libfunc;
break;
case XFmode:
libcall = extenddfxf2_libfunc;
break;
case TFmode:
libcall = extenddftf2_libfunc;
break;
default:
break;
}
break;
case XFmode:
switch (to_mode)
{
case SFmode:
libcall = truncxfsf2_libfunc;
break;
case DFmode:
libcall = truncxfdf2_libfunc;
break;
default:
break;
}
break;
case TFmode:
switch (to_mode)
{
case SFmode:
libcall = trunctfsf2_libfunc;
break;
case DFmode:
libcall = trunctfdf2_libfunc;
break;
default:
break;
}
break;
default:
break;
}
if (libcall == (rtx) 0)
/* This conversion is not implemented yet. */
abort ();
value = emit_library_call_value (libcall, NULL_RTX, 1, to_mode,
1, from, from_mode);
emit_move_insn (to, value);
return;
}
/* Now both modes are integers. */
/* Handle expanding beyond a word. */
if (GET_MODE_BITSIZE (from_mode) < GET_MODE_BITSIZE (to_mode)
&& GET_MODE_BITSIZE (to_mode) > BITS_PER_WORD)
{
rtx insns;
rtx lowpart;
rtx fill_value;
rtx lowfrom;
int i;
enum machine_mode lowpart_mode;
int nwords = CEIL (GET_MODE_SIZE (to_mode), UNITS_PER_WORD);
/* Try converting directly if the insn is supported. */
if ((code = can_extend_p (to_mode, from_mode, unsignedp))
!= CODE_FOR_nothing)
{
/* If FROM is a SUBREG, put it into a register. Do this
so that we always generate the same set of insns for
better cse'ing; if an intermediate assignment occurred,
we won't be doing the operation directly on the SUBREG. */
if (optimize > 0 && GET_CODE (from) == SUBREG)
from = force_reg (from_mode, from);
emit_unop_insn (code, to, from, equiv_code);
return;
}
/* Next, try converting via full word. */
else if (GET_MODE_BITSIZE (from_mode) < BITS_PER_WORD
&& ((code = can_extend_p (to_mode, word_mode, unsignedp))
!= CODE_FOR_nothing))
{
if (GET_CODE (to) == REG)
emit_insn (gen_rtx (CLOBBER, VOIDmode, to));
convert_move (gen_lowpart (word_mode, to), from, unsignedp);
emit_unop_insn (code, to,
gen_lowpart (word_mode, to), equiv_code);
return;
}
/* No special multiword conversion insn; do it by hand. */
start_sequence ();
/* Since we will turn this into a no conflict block, we must ensure
that the source does not overlap the target. */
if (reg_overlap_mentioned_p (to, from))
from = force_reg (from_mode, from);
/* Get a copy of FROM widened to a word, if necessary. */
if (GET_MODE_BITSIZE (from_mode) < BITS_PER_WORD)
lowpart_mode = word_mode;
else
lowpart_mode = from_mode;
lowfrom = convert_to_mode (lowpart_mode, from, unsignedp);
lowpart = gen_lowpart (lowpart_mode, to);
emit_move_insn (lowpart, lowfrom);
/* Compute the value to put in each remaining word. */
if (unsignedp)
fill_value = const0_rtx;
else
{
#ifdef HAVE_slt
if (HAVE_slt
&& insn_operand_mode[(int) CODE_FOR_slt][0] == word_mode
&& STORE_FLAG_VALUE == -1)
{
emit_cmp_insn (lowfrom, const0_rtx, NE, NULL_RTX,
lowpart_mode, 0, 0);
fill_value = gen_reg_rtx (word_mode);
emit_insn (gen_slt (fill_value));
}
else
#endif
{
fill_value
= expand_shift (RSHIFT_EXPR, lowpart_mode, lowfrom,
size_int (GET_MODE_BITSIZE (lowpart_mode) - 1),
NULL_RTX, 0);
fill_value = convert_to_mode (word_mode, fill_value, 1);
}
}
/* Fill the remaining words. */
for (i = GET_MODE_SIZE (lowpart_mode) / UNITS_PER_WORD; i < nwords; i++)
{
int index = (WORDS_BIG_ENDIAN ? nwords - i - 1 : i);
rtx subword = operand_subword (to, index, 1, to_mode);
if (subword == 0)
abort ();
if (fill_value != subword)
emit_move_insn (subword, fill_value);
}
insns = get_insns ();
end_sequence ();
emit_no_conflict_block (insns, to, from, NULL_RTX,
gen_rtx (equiv_code, to_mode, copy_rtx (from)));
return;
}
/* Truncating multi-word to a word or less. */
if (GET_MODE_BITSIZE (from_mode) > BITS_PER_WORD
&& GET_MODE_BITSIZE (to_mode) <= BITS_PER_WORD)
{
if (!((GET_CODE (from) == MEM
&& ! MEM_VOLATILE_P (from)
&& direct_load[(int) to_mode]
&& ! mode_dependent_address_p (XEXP (from, 0)))
|| GET_CODE (from) == REG
|| GET_CODE (from) == SUBREG))
from = force_reg (from_mode, from);
convert_move (to, gen_lowpart (word_mode, from), 0);
return;
}
/* Handle pointer conversion */ /* SPEE 900220 */
if (to_mode == PSImode)
{
if (from_mode != SImode)
from = convert_to_mode (SImode, from, unsignedp);
#ifdef HAVE_truncsipsi2
if (HAVE_truncsipsi2)
{
emit_unop_insn (CODE_FOR_truncsipsi2, to, from, UNKNOWN);
return;
}
#endif /* HAVE_truncsipsi2 */
abort ();
}
if (from_mode == PSImode)
{
if (to_mode != SImode)
{
from = convert_to_mode (SImode, from, unsignedp);
from_mode = SImode;
}
else
{
#ifdef HAVE_extendpsisi2
if (HAVE_extendpsisi2)
{
emit_unop_insn (CODE_FOR_extendpsisi2, to, from, UNKNOWN);
return;
}
#endif /* HAVE_extendpsisi2 */
abort ();
}
}
if (to_mode == PDImode)
{
if (from_mode != DImode)
from = convert_to_mode (DImode, from, unsignedp);
#ifdef HAVE_truncdipdi2
if (HAVE_truncdipdi2)
{
emit_unop_insn (CODE_FOR_truncdipdi2, to, from, UNKNOWN);
return;
}
#endif /* HAVE_truncdipdi2 */
abort ();
}
if (from_mode == PDImode)
{
if (to_mode != DImode)
{
from = convert_to_mode (DImode, from, unsignedp);
from_mode = DImode;
}
else
{
#ifdef HAVE_extendpdidi2
if (HAVE_extendpdidi2)
{
emit_unop_insn (CODE_FOR_extendpdidi2, to, from, UNKNOWN);
return;
}
#endif /* HAVE_extendpdidi2 */
abort ();
}
}
/* Now follow all the conversions between integers
no more than a word long. */
/* For truncation, usually we can just refer to FROM in a narrower mode. */
if (GET_MODE_BITSIZE (to_mode) < GET_MODE_BITSIZE (from_mode)
&& TRULY_NOOP_TRUNCATION (GET_MODE_BITSIZE (to_mode),
GET_MODE_BITSIZE (from_mode)))
{
if (!((GET_CODE (from) == MEM
&& ! MEM_VOLATILE_P (from)
&& direct_load[(int) to_mode]
&& ! mode_dependent_address_p (XEXP (from, 0)))
|| GET_CODE (from) == REG
|| GET_CODE (from) == SUBREG))
from = force_reg (from_mode, from);
if (GET_CODE (from) == REG && REGNO (from) < FIRST_PSEUDO_REGISTER
&& ! HARD_REGNO_MODE_OK (REGNO (from), to_mode))
from = copy_to_reg (from);
emit_move_insn (to, gen_lowpart (to_mode, from));
return;
}
/* Handle extension. */
if (GET_MODE_BITSIZE (to_mode) > GET_MODE_BITSIZE (from_mode))
{
/* Convert directly if that works. */
if ((code = can_extend_p (to_mode, from_mode, unsignedp))
!= CODE_FOR_nothing)
{
emit_unop_insn (code, to, from, equiv_code);
return;
}
else
{
enum machine_mode intermediate;
/* Search for a mode to convert via. */
for (intermediate = from_mode; intermediate != VOIDmode;
intermediate = GET_MODE_WIDER_MODE (intermediate))
if (((can_extend_p (to_mode, intermediate, unsignedp)
!= CODE_FOR_nothing)
|| (GET_MODE_SIZE (to_mode) < GET_MODE_SIZE (intermediate)
&& TRULY_NOOP_TRUNCATION (to_mode, intermediate)))
&& (can_extend_p (intermediate, from_mode, unsignedp)
!= CODE_FOR_nothing))
{
convert_move (to, convert_to_mode (intermediate, from,
unsignedp), unsignedp);
return;
}
/* No suitable intermediate mode. */
abort ();
}
}
/* Support special truncate insns for certain modes. */
if (from_mode == DImode && to_mode == SImode)
{
#ifdef HAVE_truncdisi2
if (HAVE_truncdisi2)
{
emit_unop_insn (CODE_FOR_truncdisi2, to, from, UNKNOWN);
return;
}
#endif
convert_move (to, force_reg (from_mode, from), unsignedp);
return;
}
if (from_mode == DImode && to_mode == HImode)
{
#ifdef HAVE_truncdihi2
if (HAVE_truncdihi2)
{
emit_unop_insn (CODE_FOR_truncdihi2, to, from, UNKNOWN);
return;
}
#endif
convert_move (to, force_reg (from_mode, from), unsignedp);
return;
}
if (from_mode == DImode && to_mode == QImode)
{
#ifdef HAVE_truncdiqi2
if (HAVE_truncdiqi2)
{
emit_unop_insn (CODE_FOR_truncdiqi2, to, from, UNKNOWN);
return;
}
#endif
convert_move (to, force_reg (from_mode, from), unsignedp);
return;
}
if (from_mode == SImode && to_mode == HImode)
{
#ifdef HAVE_truncsihi2
if (HAVE_truncsihi2)
{
emit_unop_insn (CODE_FOR_truncsihi2, to, from, UNKNOWN);
return;
}
#endif
convert_move (to, force_reg (from_mode, from), unsignedp);
return;
}
if (from_mode == SImode && to_mode == QImode)
{
#ifdef HAVE_truncsiqi2
if (HAVE_truncsiqi2)
{
emit_unop_insn (CODE_FOR_truncsiqi2, to, from, UNKNOWN);
return;
}
#endif
convert_move (to, force_reg (from_mode, from), unsignedp);
return;
}
if (from_mode == HImode && to_mode == QImode)
{
#ifdef HAVE_trunchiqi2
if (HAVE_trunchiqi2)
{
emit_unop_insn (CODE_FOR_trunchiqi2, to, from, UNKNOWN);
return;
}
#endif
convert_move (to, force_reg (from_mode, from), unsignedp);
return;
}
if (from_mode == TImode && to_mode == DImode)
{
#ifdef HAVE_trunctidi2
if (HAVE_trunctidi2)
{
emit_unop_insn (CODE_FOR_trunctidi2, to, from, UNKNOWN);
return;
}
#endif
convert_move (to, force_reg (from_mode, from), unsignedp);
return;
}
if (from_mode == TImode && to_mode == SImode)
{
#ifdef HAVE_trunctisi2
if (HAVE_trunctisi2)
{
emit_unop_insn (CODE_FOR_trunctisi2, to, from, UNKNOWN);
return;
}
#endif
convert_move (to, force_reg (from_mode, from), unsignedp);
return;
}
if (from_mode == TImode && to_mode == HImode)
{
#ifdef HAVE_trunctihi2
if (HAVE_trunctihi2)
{
emit_unop_insn (CODE_FOR_trunctihi2, to, from, UNKNOWN);
return;
}
#endif
convert_move (to, force_reg (from_mode, from), unsignedp);
return;
}
if (from_mode == TImode && to_mode == QImode)
{
#ifdef HAVE_trunctiqi2
if (HAVE_trunctiqi2)
{
emit_unop_insn (CODE_FOR_trunctiqi2, to, from, UNKNOWN);
return;
}
#endif
convert_move (to, force_reg (from_mode, from), unsignedp);
return;
}
/* Handle truncation of volatile memrefs, and so on;
the things that couldn't be truncated directly,
and for which there was no special instruction. */
if (GET_MODE_BITSIZE (to_mode) < GET_MODE_BITSIZE (from_mode))
{
rtx temp = force_reg (to_mode, gen_lowpart (to_mode, from));
emit_move_insn (to, temp);
return;
}
/* Mode combination is not recognized. */
abort ();
}
/* Return an rtx for a value that would result
from converting X to mode MODE.
Both X and MODE may be floating, or both integer.
UNSIGNEDP is nonzero if X is an unsigned value.
This can be done by referring to a part of X in place
or by copying to a new temporary with conversion.
This function *must not* call protect_from_queue
except when putting X into an insn (in which case convert_move does it). */
rtx
convert_to_mode (mode, x, unsignedp)
enum machine_mode mode;
rtx x;
int unsignedp;
{
return convert_modes (mode, VOIDmode, x, unsignedp);
}
/* Return an rtx for a value that would result
from converting X from mode OLDMODE to mode MODE.
Both modes may be floating, or both integer.
UNSIGNEDP is nonzero if X is an unsigned value.
This can be done by referring to a part of X in place
or by copying to a new temporary with conversion.
You can give VOIDmode for OLDMODE, if you are sure X has a nonvoid mode.
This function *must not* call protect_from_queue
except when putting X into an insn (in which case convert_move does it). */
rtx
convert_modes (mode, oldmode, x, unsignedp)
enum machine_mode mode, oldmode;
rtx x;
int unsignedp;
{
register rtx temp;
/* If FROM is a SUBREG that indicates that we have already done at least
the required extension, strip it. */
if (GET_CODE (x) == SUBREG && SUBREG_PROMOTED_VAR_P (x)
&& GET_MODE_SIZE (GET_MODE (SUBREG_REG (x))) >= GET_MODE_SIZE (mode)
&& SUBREG_PROMOTED_UNSIGNED_P (x) == unsignedp)
x = gen_lowpart (mode, x);
if (GET_MODE (x) != VOIDmode)
oldmode = GET_MODE (x);
if (mode == oldmode)
return x;
/* There is one case that we must handle specially: If we are converting
a CONST_INT into a mode whose size is twice HOST_BITS_PER_WIDE_INT and
we are to interpret the constant as unsigned, gen_lowpart will do
the wrong if the constant appears negative. What we want to do is
make the high-order word of the constant zero, not all ones. */
if (unsignedp && GET_MODE_CLASS (mode) == MODE_INT
&& GET_MODE_BITSIZE (mode) == 2 * HOST_BITS_PER_WIDE_INT
&& GET_CODE (x) == CONST_INT && INTVAL (x) < 0)
{
HOST_WIDE_INT val = INTVAL (x);
if (oldmode != VOIDmode
&& HOST_BITS_PER_WIDE_INT > GET_MODE_BITSIZE (oldmode))
{
int width = GET_MODE_BITSIZE (oldmode);
/* We need to zero extend VAL. */
val &= ((HOST_WIDE_INT) 1 << width) - 1;
}
return immed_double_const (val, (HOST_WIDE_INT) 0, mode);
}
/* We can do this with a gen_lowpart if both desired and current modes
are integer, and this is either a constant integer, a register, or a
non-volatile MEM. Except for the constant case where MODE is no
wider than HOST_BITS_PER_WIDE_INT, we must be narrowing the operand. */
if ((GET_CODE (x) == CONST_INT
&& GET_MODE_BITSIZE (mode) <= HOST_BITS_PER_WIDE_INT)
|| (GET_MODE_CLASS (mode) == MODE_INT
&& GET_MODE_CLASS (oldmode) == MODE_INT
&& (GET_CODE (x) == CONST_DOUBLE
|| (GET_MODE_SIZE (mode) <= GET_MODE_SIZE (oldmode)
&& ((GET_CODE (x) == MEM && ! MEM_VOLATILE_P (x)
&& direct_load[(int) mode])
|| (GET_CODE (x) == REG
&& TRULY_NOOP_TRUNCATION (GET_MODE_BITSIZE (mode),
GET_MODE_BITSIZE (GET_MODE (x)))))))))
{
/* ?? If we don't know OLDMODE, we have to assume here that
X does not need sign- or zero-extension. This may not be
the case, but it's the best we can do. */
if (GET_CODE (x) == CONST_INT && oldmode != VOIDmode
&& GET_MODE_SIZE (mode) > GET_MODE_SIZE (oldmode))
{
HOST_WIDE_INT val = INTVAL (x);
int width = GET_MODE_BITSIZE (oldmode);
/* We must sign or zero-extend in this case. Start by
zero-extending, then sign extend if we need to. */
val &= ((HOST_WIDE_INT) 1 << width) - 1;
if (! unsignedp
&& (val & ((HOST_WIDE_INT) 1 << (width - 1))))
val |= (HOST_WIDE_INT) (-1) << width;
return GEN_INT (val);
}
return gen_lowpart (mode, x);
}
temp = gen_reg_rtx (mode);
convert_move (temp, x, unsignedp);
return temp;
}
/* Generate several move instructions to copy LEN bytes
from block FROM to block TO. (These are MEM rtx's with BLKmode).
The caller must pass FROM and TO
through protect_from_queue before calling.
ALIGN (in bytes) is maximum alignment we can assume. */
static void
move_by_pieces (to, from, len, align)
rtx to, from;
int len, align;
{
struct move_by_pieces data;
rtx to_addr = XEXP (to, 0), from_addr = XEXP (from, 0);
int max_size = MOVE_MAX + 1;
data.offset = 0;
data.to_addr = to_addr;
data.from_addr = from_addr;
data.to = to;
data.from = from;
data.autinc_to
= (GET_CODE (to_addr) == PRE_INC || GET_CODE (to_addr) == PRE_DEC
|| GET_CODE (to_addr) == POST_INC || GET_CODE (to_addr) == POST_DEC);
data.autinc_from
= (GET_CODE (from_addr) == PRE_INC || GET_CODE (from_addr) == PRE_DEC
|| GET_CODE (from_addr) == POST_INC
|| GET_CODE (from_addr) == POST_DEC);
data.explicit_inc_from = 0;
data.explicit_inc_to = 0;
data.reverse
= (GET_CODE (to_addr) == PRE_DEC || GET_CODE (to_addr) == POST_DEC);
if (data.reverse) data.offset = len;
data.len = len;
data.to_struct = MEM_IN_STRUCT_P (to);
data.from_struct = MEM_IN_STRUCT_P (from);
/* If copying requires more than two move insns,
copy addresses to registers (to make displacements shorter)
and use post-increment if available. */
if (!(data.autinc_from && data.autinc_to)
&& move_by_pieces_ninsns (len, align) > 2)
{
#ifdef HAVE_PRE_DECREMENT
if (data.reverse && ! data.autinc_from)
{
data.from_addr = copy_addr_to_reg (plus_constant (from_addr, len));
data.autinc_from = 1;
data.explicit_inc_from = -1;
}
#endif
#ifdef HAVE_POST_INCREMENT
if (! data.autinc_from)
{
data.from_addr = copy_addr_to_reg (from_addr);
data.autinc_from = 1;
data.explicit_inc_from = 1;
}
#endif
if (!data.autinc_from && CONSTANT_P (from_addr))
data.from_addr = copy_addr_to_reg (from_addr);
#ifdef HAVE_PRE_DECREMENT
if (data.reverse && ! data.autinc_to)
{
data.to_addr = copy_addr_to_reg (plus_constant (to_addr, len));
data.autinc_to = 1;
data.explicit_inc_to = -1;
}
#endif
#ifdef HAVE_POST_INCREMENT
if (! data.reverse && ! data.autinc_to)
{
data.to_addr = copy_addr_to_reg (to_addr);
data.autinc_to = 1;
data.explicit_inc_to = 1;
}
#endif
if (!data.autinc_to && CONSTANT_P (to_addr))
data.to_addr = copy_addr_to_reg (to_addr);
}
if (! SLOW_UNALIGNED_ACCESS
|| align > MOVE_MAX || align >= BIGGEST_ALIGNMENT / BITS_PER_UNIT)
align = MOVE_MAX;
/* First move what we can in the largest integer mode, then go to
successively smaller modes. */
while (max_size > 1)
{
enum machine_mode mode = VOIDmode, tmode;
enum insn_code icode;
for (tmode = GET_CLASS_NARROWEST_MODE (MODE_INT);
tmode != VOIDmode; tmode = GET_MODE_WIDER_MODE (tmode))
if (GET_MODE_SIZE (tmode) < max_size)
mode = tmode;
if (mode == VOIDmode)
break;
icode = mov_optab->handlers[(int) mode].insn_code;
if (icode != CODE_FOR_nothing
&& align >= MIN (BIGGEST_ALIGNMENT / BITS_PER_UNIT,
GET_MODE_SIZE (mode)))
move_by_pieces_1 (GEN_FCN (icode), mode, &data);
max_size = GET_MODE_SIZE (mode);
}
/* The code above should have handled everything. */
if (data.len > 0)
abort ();
}
/* Return number of insns required to move L bytes by pieces.
ALIGN (in bytes) is maximum alignment we can assume. */
static int
move_by_pieces_ninsns (l, align)
unsigned int l;
int align;
{
register int n_insns = 0;
int max_size = MOVE_MAX + 1;
if (! SLOW_UNALIGNED_ACCESS
|| align > MOVE_MAX || align >= BIGGEST_ALIGNMENT / BITS_PER_UNIT)
align = MOVE_MAX;
while (max_size > 1)
{
enum machine_mode mode = VOIDmode, tmode;
enum insn_code icode;
for (tmode = GET_CLASS_NARROWEST_MODE (MODE_INT);
tmode != VOIDmode; tmode = GET_MODE_WIDER_MODE (tmode))
if (GET_MODE_SIZE (tmode) < max_size)
mode = tmode;
if (mode == VOIDmode)
break;
icode = mov_optab->handlers[(int) mode].insn_code;
if (icode != CODE_FOR_nothing
&& align >= MIN (BIGGEST_ALIGNMENT / BITS_PER_UNIT,
GET_MODE_SIZE (mode)))
n_insns += l / GET_MODE_SIZE (mode), l %= GET_MODE_SIZE (mode);
max_size = GET_MODE_SIZE (mode);
}
return n_insns;
}
/* Subroutine of move_by_pieces. Move as many bytes as appropriate
with move instructions for mode MODE. GENFUN is the gen_... function
to make a move insn for that mode. DATA has all the other info. */
static void
move_by_pieces_1 (genfun, mode, data)
rtx (*genfun) ();
enum machine_mode mode;
struct move_by_pieces *data;
{
register int size = GET_MODE_SIZE (mode);
register rtx to1, from1;
while (data->len >= size)
{
if (data->reverse) data->offset -= size;
to1 = (data->autinc_to
? gen_rtx (MEM, mode, data->to_addr)
: copy_rtx (change_address (data->to, mode,
plus_constant (data->to_addr,
data->offset))));
MEM_IN_STRUCT_P (to1) = data->to_struct;
from1
= (data->autinc_from
? gen_rtx (MEM, mode, data->from_addr)
: copy_rtx (change_address (data->from, mode,
plus_constant (data->from_addr,
data->offset))));
MEM_IN_STRUCT_P (from1) = data->from_struct;
#ifdef HAVE_PRE_DECREMENT
if (data->explicit_inc_to < 0)
emit_insn (gen_add2_insn (data->to_addr, GEN_INT (-size)));
if (data->explicit_inc_from < 0)
emit_insn (gen_add2_insn (data->from_addr, GEN_INT (-size)));
#endif
emit_insn ((*genfun) (to1, from1));
#ifdef HAVE_POST_INCREMENT
if (data->explicit_inc_to > 0)
emit_insn (gen_add2_insn (data->to_addr, GEN_INT (size)));
if (data->explicit_inc_from > 0)
emit_insn (gen_add2_insn (data->from_addr, GEN_INT (size)));
#endif
if (! data->reverse) data->offset += size;
data->len -= size;
}
}
/* Emit code to move a block Y to a block X.
This may be done with string-move instructions,
with multiple scalar move instructions, or with a library call.
Both X and Y must be MEM rtx's (perhaps inside VOLATILE)
with mode BLKmode.
SIZE is an rtx that says how long they are.
ALIGN is the maximum alignment we can assume they have,
measured in bytes.
Return the address of the new block, if memcpy is called and returns it,
0 otherwise. */
rtx
emit_block_move (x, y, size, align)
rtx x, y;
rtx size;
int align;
{
rtx retval = 0;
if (GET_MODE (x) != BLKmode)
abort ();
if (GET_MODE (y) != BLKmode)
abort ();
x = protect_from_queue (x, 1);
y = protect_from_queue (y, 0);
size = protect_from_queue (size, 0);
if (GET_CODE (x) != MEM)
abort ();
if (GET_CODE (y) != MEM)
abort ();
if (size == 0)
abort ();
if (GET_CODE (size) == CONST_INT
&& (move_by_pieces_ninsns (INTVAL (size), align) < MOVE_RATIO))
move_by_pieces (x, y, INTVAL (size), align);
else
{
/* Try the most limited insn first, because there's no point
including more than one in the machine description unless
the more limited one has some advantage. */
rtx opalign = GEN_INT (align);
enum machine_mode mode;
for (mode = GET_CLASS_NARROWEST_MODE (MODE_INT); mode != VOIDmode;
mode = GET_MODE_WIDER_MODE (mode))
{
enum insn_code code = movstr_optab[(int) mode];
if (code != CODE_FOR_nothing
/* We don't need MODE to be narrower than BITS_PER_HOST_WIDE_INT
here because if SIZE is less than the mode mask, as it is
returned by the macro, it will definitely be less than the
actual mode mask. */
&& ((GET_CODE (size) == CONST_INT
&& ((unsigned HOST_WIDE_INT) INTVAL (size)
<= GET_MODE_MASK (mode)))
|| GET_MODE_BITSIZE (mode) >= BITS_PER_WORD)
&& (insn_operand_predicate[(int) code][0] == 0
|| (*insn_operand_predicate[(int) code][0]) (x, BLKmode))
&& (insn_operand_predicate[(int) code][1] == 0
|| (*insn_operand_predicate[(int) code][1]) (y, BLKmode))
&& (insn_operand_predicate[(int) code][3] == 0
|| (*insn_operand_predicate[(int) code][3]) (opalign,
VOIDmode)))
{
rtx op2;
rtx last = get_last_insn ();
rtx pat;
op2 = convert_to_mode (mode, size, 1);
if (insn_operand_predicate[(int) code][2] != 0
&& ! (*insn_operand_predicate[(int) code][2]) (op2, mode))
op2 = copy_to_mode_reg (mode, op2);
pat = GEN_FCN ((int) code) (x, y, op2, opalign);
if (pat)
{
emit_insn (pat);
return 0;
}
else
delete_insns_since (last);
}
}
#ifdef TARGET_MEM_FUNCTIONS
retval
= emit_library_call_value (memcpy_libfunc, NULL_RTX, 0,
ptr_mode, 3, XEXP (x, 0), Pmode,
XEXP (y, 0), Pmode,
convert_to_mode (TYPE_MODE (sizetype), size,
TREE_UNSIGNED (sizetype)),
TYPE_MODE (sizetype));
#else
emit_library_call (bcopy_libfunc, 0,
VOIDmode, 3, XEXP (y, 0), Pmode,
XEXP (x, 0), Pmode,
convert_to_mode (TYPE_MODE (integer_type_node), size,
TREE_UNSIGNED (integer_type_node)),
TYPE_MODE (integer_type_node));
#endif
}
return retval;
}
/* Copy all or part of a value X into registers starting at REGNO.
The number of registers to be filled is NREGS. */
void
move_block_to_reg (regno, x, nregs, mode)
int regno;
rtx x;
int nregs;
enum machine_mode mode;
{
int i;
rtx pat, last;
if (nregs == 0)
return;
if (CONSTANT_P (x) && ! LEGITIMATE_CONSTANT_P (x))
x = validize_mem (force_const_mem (mode, x));
/* See if the machine can do this with a load multiple insn. */
#ifdef HAVE_load_multiple
if (HAVE_load_multiple)
{
last = get_last_insn ();
pat = gen_load_multiple (gen_rtx (REG, word_mode, regno), x,
GEN_INT (nregs));
if (pat)
{
emit_insn (pat);
return;
}
else
delete_insns_since (last);
}
#endif
for (i = 0; i < nregs; i++)
emit_move_insn (gen_rtx (REG, word_mode, regno + i),
operand_subword_force (x, i, mode));
}
/* Copy all or part of a BLKmode value X out of registers starting at REGNO.
The number of registers to be filled is NREGS. SIZE indicates the number
of bytes in the object X. */
void
move_block_from_reg (regno, x, nregs, size)
int regno;
rtx x;
int nregs;
int size;
{
int i;
rtx pat, last;
enum machine_mode mode;
/* If SIZE is that of a mode no bigger than a word, just use that
mode's store operation. */
if (size <= UNITS_PER_WORD
&& (mode = mode_for_size (size * BITS_PER_UNIT, MODE_INT, 0)) != BLKmode)
{
emit_move_insn (change_address (x, mode, NULL),
gen_rtx (REG, mode, regno));
return;
}
/* Blocks smaller than a word on a BYTES_BIG_ENDIAN machine must be aligned
to the left before storing to memory. Note that the previous test
doesn't handle all cases (e.g. SIZE == 3). */
if (size < UNITS_PER_WORD && BYTES_BIG_ENDIAN)
{
rtx tem = operand_subword (x, 0, 1, BLKmode);
rtx shift;
if (tem == 0)
abort ();
shift = expand_shift (LSHIFT_EXPR, word_mode,
gen_rtx (REG, word_mode, regno),
build_int_2 ((UNITS_PER_WORD - size)
* BITS_PER_UNIT, 0), NULL_RTX, 0);
emit_move_insn (tem, shift);
return;
}
/* See if the machine can do this with a store multiple insn. */
#ifdef HAVE_store_multiple
if (HAVE_store_multiple)
{
last = get_last_insn ();
pat = gen_store_multiple (x, gen_rtx (REG, word_mode, regno),
GEN_INT (nregs));
if (pat)
{
emit_insn (pat);
return;
}
else
delete_insns_since (last);
}
#endif
for (i = 0; i < nregs; i++)
{
rtx tem = operand_subword (x, i, 1, BLKmode);
if (tem == 0)
abort ();
emit_move_insn (tem, gen_rtx (REG, word_mode, regno + i));
}
}
/* Emit code to move a block Y to a block X, where X is non-consecutive
registers represented by a PARALLEL. */
void
emit_group_load (x, y)
rtx x, y;
{
rtx target_reg, source;
int i;
if (GET_CODE (x) != PARALLEL)
abort ();
/* Check for a NULL entry, used to indicate that the parameter goes
both on the stack and in registers. */
if (XEXP (XVECEXP (x, 0, 0), 0))
i = 0;
else
i = 1;
for (; i < XVECLEN (x, 0); i++)
{
rtx element = XVECEXP (x, 0, i);
target_reg = XEXP (element, 0);
if (GET_CODE (y) == MEM)
source = change_address (y, GET_MODE (target_reg),
plus_constant (XEXP (y, 0),
INTVAL (XEXP (element, 1))));
else if (XEXP (element, 1) == const0_rtx)
{
if (GET_MODE (target_reg) == GET_MODE (y))
source = y;
/* Allow for the target_reg to be smaller than the input register
to allow for AIX with 4 DF arguments after a single SI arg. The
last DF argument will only load 1 word into the integer registers,
but load a DF value into the float registers. */
else if ((GET_MODE_SIZE (GET_MODE (target_reg))
<= GET_MODE_SIZE (GET_MODE (y)))
&& GET_MODE (target_reg) == word_mode)
/* This might be a const_double, so we can't just use SUBREG. */
source = operand_subword (y, 0, 0, VOIDmode);
else if (GET_MODE_SIZE (GET_MODE (target_reg))
== GET_MODE_SIZE (GET_MODE (y)))
source = gen_lowpart (GET_MODE (target_reg), y);
else
abort ();
}
else
abort ();
emit_move_insn (target_reg, source);
}
}
/* Emit code to move a block Y to a block X, where Y is non-consecutive
registers represented by a PARALLEL. */
void
emit_group_store (x, y)
rtx x, y;
{
rtx source_reg, target;
int i;
if (GET_CODE (y) != PARALLEL)
abort ();
/* Check for a NULL entry, used to indicate that the parameter goes
both on the stack and in registers. */
if (XEXP (XVECEXP (y, 0, 0), 0))
i = 0;
else
i = 1;
for (; i < XVECLEN (y, 0); i++)
{
rtx element = XVECEXP (y, 0, i);
source_reg = XEXP (element, 0);
if (GET_CODE (x) == MEM)
target = change_address (x, GET_MODE (source_reg),
plus_constant (XEXP (x, 0),
INTVAL (XEXP (element, 1))));
else if (XEXP (element, 1) == const0_rtx)
{
target = x;
if (GET_MODE (target) != GET_MODE (source_reg))
target = gen_lowpart (GET_MODE (source_reg), target);
}
else
abort ();
emit_move_insn (target, source_reg);
}
}
/* Add a USE expression for REG to the (possibly empty) list pointed
to by CALL_FUSAGE. REG must denote a hard register. */
void
use_reg (call_fusage, reg)
rtx *call_fusage, reg;
{
if (GET_CODE (reg) != REG
|| REGNO (reg) >= FIRST_PSEUDO_REGISTER)
abort();
*call_fusage
= gen_rtx (EXPR_LIST, VOIDmode,
gen_rtx (USE, VOIDmode, reg), *call_fusage);
}
/* Add USE expressions to *CALL_FUSAGE for each of NREGS consecutive regs,
starting at REGNO. All of these registers must be hard registers. */
void
use_regs (call_fusage, regno, nregs)
rtx *call_fusage;
int regno;
int nregs;
{
int i;
if (regno + nregs > FIRST_PSEUDO_REGISTER)
abort ();
for (i = 0; i < nregs; i++)
use_reg (call_fusage, gen_rtx (REG, reg_raw_mode[regno + i], regno + i));
}
/* Add USE expressions to *CALL_FUSAGE for each REG contained in the
PARALLEL REGS. This is for calls that pass values in multiple
non-contiguous locations. The Irix 6 ABI has examples of this. */
void
use_group_regs (call_fusage, regs)
rtx *call_fusage;
rtx regs;
{
int i;
for (i = 0; i < XVECLEN (regs, 0); i++)
{
rtx reg = XEXP (XVECEXP (regs, 0, i), 0);
/* A NULL entry means the parameter goes both on the stack and in
registers. This can also be a MEM for targets that pass values
partially on the stack and partially in registers. */
if (reg != 0 && GET_CODE (reg) == REG)
use_reg (call_fusage, reg);
}
}
/* Generate several move instructions to clear LEN bytes of block TO.
(A MEM rtx with BLKmode). The caller must pass TO through
protect_from_queue before calling. ALIGN (in bytes) is maximum alignment
we can assume. */
static void
clear_by_pieces (to, len, align)
rtx to;
int len, align;
{
struct clear_by_pieces data;
rtx to_addr = XEXP (to, 0);
int max_size = MOVE_MAX + 1;
data.offset = 0;
data.to_addr = to_addr;
data.to = to;
data.autinc_to
= (GET_CODE (to_addr) == PRE_INC || GET_CODE (to_addr) == PRE_DEC
|| GET_CODE (to_addr) == POST_INC || GET_CODE (to_addr) == POST_DEC);
data.explicit_inc_to = 0;
data.reverse
= (GET_CODE (to_addr) == PRE_DEC || GET_CODE (to_addr) == POST_DEC);
if (data.reverse) data.offset = len;
data.len = len;
data.to_struct = MEM_IN_STRUCT_P (to);
/* If copying requires more than two move insns,
copy addresses to registers (to make displacements shorter)
and use post-increment if available. */
if (!data.autinc_to
&& move_by_pieces_ninsns (len, align) > 2)
{
#ifdef HAVE_PRE_DECREMENT
if (data.reverse && ! data.autinc_to)
{
data.to_addr = copy_addr_to_reg (plus_constant (to_addr, len));
data.autinc_to = 1;
data.explicit_inc_to = -1;
}
#endif
#ifdef HAVE_POST_INCREMENT
if (! data.reverse && ! data.autinc_to)
{
data.to_addr = copy_addr_to_reg (to_addr);
data.autinc_to = 1;
data.explicit_inc_to = 1;
}
#endif
if (!data.autinc_to && CONSTANT_P (to_addr))
data.to_addr = copy_addr_to_reg (to_addr);
}
if (! SLOW_UNALIGNED_ACCESS
|| align > MOVE_MAX || align >= BIGGEST_ALIGNMENT / BITS_PER_UNIT)
align = MOVE_MAX;
/* First move what we can in the largest integer mode, then go to
successively smaller modes. */
while (max_size > 1)
{
enum machine_mode mode = VOIDmode, tmode;
enum insn_code icode;
for (tmode = GET_CLASS_NARROWEST_MODE (MODE_INT);
tmode != VOIDmode; tmode = GET_MODE_WIDER_MODE (tmode))
if (GET_MODE_SIZE (tmode) < max_size)
mode = tmode;
if (mode == VOIDmode)
break;
icode = mov_optab->handlers[(int) mode].insn_code;
if (icode != CODE_FOR_nothing
&& align >= MIN (BIGGEST_ALIGNMENT / BITS_PER_UNIT,
GET_MODE_SIZE (mode)))
clear_by_pieces_1 (GEN_FCN (icode), mode, &data);
max_size = GET_MODE_SIZE (mode);
}
/* The code above should have handled everything. */
if (data.len != 0)
abort ();
}
/* Subroutine of clear_by_pieces. Clear as many bytes as appropriate
with move instructions for mode MODE. GENFUN is the gen_... function
to make a move insn for that mode. DATA has all the other info. */
static void
clear_by_pieces_1 (genfun, mode, data)
rtx (*genfun) ();
enum machine_mode mode;
struct clear_by_pieces *data;
{
register int size = GET_MODE_SIZE (mode);
register rtx to1;
while (data->len >= size)
{
if (data->reverse) data->offset -= size;
to1 = (data->autinc_to
? gen_rtx (MEM, mode, data->to_addr)
: copy_rtx (change_address (data->to, mode,
plus_constant (data->to_addr,
data->offset))));
MEM_IN_STRUCT_P (to1) = data->to_struct;
#ifdef HAVE_PRE_DECREMENT
if (data->explicit_inc_to < 0)
emit_insn (gen_add2_insn (data->to_addr, GEN_INT (-size)));
#endif
emit_insn ((*genfun) (to1, const0_rtx));
#ifdef HAVE_POST_INCREMENT
if (data->explicit_inc_to > 0)
emit_insn (gen_add2_insn (data->to_addr, GEN_INT (size)));
#endif
if (! data->reverse) data->offset += size;
data->len -= size;
}
}
/* Write zeros through the storage of OBJECT.
If OBJECT has BLKmode, SIZE is its length in bytes and ALIGN is
the maximum alignment we can is has, measured in bytes.
If we call a function that returns the length of the block, return it. */
rtx
clear_storage (object, size, align)
rtx object;
rtx size;
int align;
{
rtx retval = 0;
if (GET_MODE (object) == BLKmode)
{
object = protect_from_queue (object, 1);
size = protect_from_queue (size, 0);
if (GET_CODE (size) == CONST_INT
&& (move_by_pieces_ninsns (INTVAL (size), align) < MOVE_RATIO))
clear_by_pieces (object, INTVAL (size), align);
else
{
/* Try the most limited insn first, because there's no point
including more than one in the machine description unless
the more limited one has some advantage. */
rtx opalign = GEN_INT (align);
enum machine_mode mode;
for (mode = GET_CLASS_NARROWEST_MODE (MODE_INT); mode != VOIDmode;
mode = GET_MODE_WIDER_MODE (mode))
{
enum insn_code code = clrstr_optab[(int) mode];
if (code != CODE_FOR_nothing
/* We don't need MODE to be narrower than
BITS_PER_HOST_WIDE_INT here because if SIZE is less than
the mode mask, as it is returned by the macro, it will
definitely be less than the actual mode mask. */
&& ((GET_CODE (size) == CONST_INT
&& ((unsigned HOST_WIDE_INT) INTVAL (size)
<= GET_MODE_MASK (mode)))
|| GET_MODE_BITSIZE (mode) >= BITS_PER_WORD)
&& (insn_operand_predicate[(int) code][0] == 0
|| (*insn_operand_predicate[(int) code][0]) (object,
BLKmode))
&& (insn_operand_predicate[(int) code][2] == 0
|| (*insn_operand_predicate[(int) code][2]) (opalign,
VOIDmode)))
{
rtx op1;
rtx last = get_last_insn ();
rtx pat;
op1 = convert_to_mode (mode, size, 1);
if (insn_operand_predicate[(int) code][1] != 0
&& ! (*insn_operand_predicate[(int) code][1]) (op1,
mode))
op1 = copy_to_mode_reg (mode, op1);
pat = GEN_FCN ((int) code) (object, op1, opalign);
if (pat)
{
emit_insn (pat);
return 0;
}
else
delete_insns_since (last);
}
}
#ifdef TARGET_MEM_FUNCTIONS
retval
= emit_library_call_value (memset_libfunc, NULL_RTX, 0,
ptr_mode, 3,
XEXP (object, 0), Pmode,
const0_rtx,
TYPE_MODE (integer_type_node),
convert_to_mode
(TYPE_MODE (sizetype), size,
TREE_UNSIGNED (sizetype)),
TYPE_MODE (sizetype));
#else
emit_library_call (bzero_libfunc, 0,
VOIDmode, 2,
XEXP (object, 0), Pmode,
convert_to_mode
(TYPE_MODE (integer_type_node), size,
TREE_UNSIGNED (integer_type_node)),
TYPE_MODE (integer_type_node));
#endif
}
}
else
emit_move_insn (object, CONST0_RTX (GET_MODE (object)));
return retval;
}
/* Generate code to copy Y into X.
Both Y and X must have the same mode, except that
Y can be a constant with VOIDmode.
This mode cannot be BLKmode; use emit_block_move for that.
Return the last instruction emitted. */
rtx
emit_move_insn (x, y)
rtx x, y;
{
enum machine_mode mode = GET_MODE (x);
x = protect_from_queue (x, 1);
y = protect_from_queue (y, 0);
if (mode == BLKmode || (GET_MODE (y) != mode && GET_MODE (y) != VOIDmode))
abort ();
if (CONSTANT_P (y) && ! LEGITIMATE_CONSTANT_P (y))
y = force_const_mem (mode, y);
/* If X or Y are memory references, verify that their addresses are valid
for the machine. */
if (GET_CODE (x) == MEM
&& ((! memory_address_p (GET_MODE (x), XEXP (x, 0))
&& ! push_operand (x, GET_MODE (x)))
|| (flag_force_addr
&& CONSTANT_ADDRESS_P (XEXP (x, 0)))))
x = change_address (x, VOIDmode, XEXP (x, 0));
if (GET_CODE (y) == MEM
&& (! memory_address_p (GET_MODE (y), XEXP (y, 0))
|| (flag_force_addr
&& CONSTANT_ADDRESS_P (XEXP (y, 0)))))
y = change_address (y, VOIDmode, XEXP (y, 0));
if (mode == BLKmode)
abort ();
return emit_move_insn_1 (x, y);
}
/* Low level part of emit_move_insn.
Called just like emit_move_insn, but assumes X and Y
are basically valid. */
rtx
emit_move_insn_1 (x, y)
rtx x, y;
{
enum machine_mode mode = GET_MODE (x);
enum machine_mode submode;
enum mode_class class = GET_MODE_CLASS (mode);
int i;
if (mov_optab->handlers[(int) mode].insn_code != CODE_FOR_nothing)
return
emit_insn (GEN_FCN (mov_optab->handlers[(int) mode].insn_code) (x, y));
/* Expand complex moves by moving real part and imag part, if possible. */
else if ((class == MODE_COMPLEX_FLOAT || class == MODE_COMPLEX_INT)
&& BLKmode != (submode = mode_for_size ((GET_MODE_UNIT_SIZE (mode)
* BITS_PER_UNIT),
(class == MODE_COMPLEX_INT
? MODE_INT : MODE_FLOAT),
0))
&& (mov_optab->handlers[(int) submode].insn_code
!= CODE_FOR_nothing))
{
/* Don't split destination if it is a stack push. */
int stack = push_operand (x, GET_MODE (x));
rtx insns;
/* If this is a stack, push the highpart first, so it
will be in the argument order.
In that case, change_address is used only to convert
the mode, not to change the address. */
if (stack)
{
/* Note that the real part always precedes the imag part in memory
regardless of machine's endianness. */
#ifdef STACK_GROWS_DOWNWARD
emit_insn (GEN_FCN (mov_optab->handlers[(int) submode].insn_code)
(gen_rtx (MEM, submode, (XEXP (x, 0))),
gen_imagpart (submode, y)));
emit_insn (GEN_FCN (mov_optab->handlers[(int) submode].insn_code)
(gen_rtx (MEM, submode, (XEXP (x, 0))),
gen_realpart (submode, y)));
#else
emit_insn (GEN_FCN (mov_optab->handlers[(int) submode].insn_code)
(gen_rtx (MEM, submode, (XEXP (x, 0))),
gen_realpart (submode, y)));
emit_insn (GEN_FCN (mov_optab->handlers[(int) submode].insn_code)
(gen_rtx (MEM, submode, (XEXP (x, 0))),
gen_imagpart (submode, y)));
#endif
}
else
{
emit_insn (GEN_FCN (mov_optab->handlers[(int) submode].insn_code)
(gen_realpart (submode, x), gen_realpart (submode, y)));
emit_insn (GEN_FCN (mov_optab->handlers[(int) submode].insn_code)
(gen_imagpart (submode, x), gen_imagpart (submode, y)));
}
return get_last_insn ();
}
/* This will handle any multi-word mode that lacks a move_insn pattern.
However, you will get better code if you define such patterns,
even if they must turn into multiple assembler instructions. */
else if (GET_MODE_SIZE (mode) > UNITS_PER_WORD)
{
rtx last_insn = 0;
rtx insns;
#ifdef PUSH_ROUNDING
/* If X is a push on the stack, do the push now and replace
X with a reference to the stack pointer. */
if (push_operand (x, GET_MODE (x)))
{
anti_adjust_stack (GEN_INT (GET_MODE_SIZE (GET_MODE (x))));
x = change_address (x, VOIDmode, stack_pointer_rtx);
}
#endif
/* Show the output dies here. */
if (x != y)
emit_insn (gen_rtx (CLOBBER, VOIDmode, x));
for (i = 0;
i < (GET_MODE_SIZE (mode) + (UNITS_PER_WORD - 1)) / UNITS_PER_WORD;
i++)
{
rtx xpart = operand_subword (x, i, 1, mode);
rtx ypart = operand_subword (y, i, 1, mode);
/* If we can't get a part of Y, put Y into memory if it is a
constant. Otherwise, force it into a register. If we still
can't get a part of Y, abort. */
if (ypart == 0 && CONSTANT_P (y))
{
y = force_const_mem (mode, y);
ypart = operand_subword (y, i, 1, mode);
}
else if (ypart == 0)
ypart = operand_subword_force (y, i, mode);
if (xpart == 0 || ypart == 0)
abort ();
last_insn = emit_move_insn (xpart, ypart);
}
return last_insn;
}
else
abort ();
}
/* Pushing data onto the stack. */
/* Push a block of length SIZE (perhaps variable)
and return an rtx to address the beginning of the block.
Note that it is not possible for the value returned to be a QUEUED.
The value may be virtual_outgoing_args_rtx.
EXTRA is the number of bytes of padding to push in addition to SIZE.
BELOW nonzero means this padding comes at low addresses;
otherwise, the padding comes at high addresses. */
rtx
push_block (size, extra, below)
rtx size;
int extra, below;
{
register rtx temp;
size = convert_modes (Pmode, ptr_mode, size, 1);
if (CONSTANT_P (size))
anti_adjust_stack (plus_constant (size, extra));
else if (GET_CODE (size) == REG && extra == 0)
anti_adjust_stack (size);
else
{
rtx temp = copy_to_mode_reg (Pmode, size);
if (extra != 0)
temp = expand_binop (Pmode, add_optab, temp, GEN_INT (extra),
temp, 0, OPTAB_LIB_WIDEN);
anti_adjust_stack (temp);
}
#ifdef STACK_GROWS_DOWNWARD
temp = virtual_outgoing_args_rtx;
if (extra != 0 && below)
temp = plus_constant (temp, extra);
#else
if (GET_CODE (size) == CONST_INT)
temp = plus_constant (virtual_outgoing_args_rtx,
- INTVAL (size) - (below ? 0 : extra));
else if (extra != 0 && !below)
temp = gen_rtx (PLUS, Pmode, virtual_outgoing_args_rtx,
negate_rtx (Pmode, plus_constant (size, extra)));
else
temp = gen_rtx (PLUS, Pmode, virtual_outgoing_args_rtx,
negate_rtx (Pmode, size));
#endif
return memory_address (GET_CLASS_NARROWEST_MODE (MODE_INT), temp);
}
rtx
gen_push_operand ()
{
return gen_rtx (STACK_PUSH_CODE, Pmode, stack_pointer_rtx);
}
/* Return an rtx for the address of the beginning of a as-if-it-was-pushed
block of SIZE bytes. */
static rtx
get_push_address (size)
int size;
{
register rtx temp;
if (STACK_PUSH_CODE == POST_DEC)
temp = gen_rtx (PLUS, Pmode, stack_pointer_rtx, GEN_INT (size));
else if (STACK_PUSH_CODE == POST_INC)
temp = gen_rtx (MINUS, Pmode, stack_pointer_rtx, GEN_INT (size));
else
temp = stack_pointer_rtx;
return copy_to_reg (temp);
}
/* Generate code to push X onto the stack, assuming it has mode MODE and
type TYPE.
MODE is redundant except when X is a CONST_INT (since they don't
carry mode info).
SIZE is an rtx for the size of data to be copied (in bytes),
needed only if X is BLKmode.
ALIGN (in bytes) is maximum alignment we can assume.
If PARTIAL and REG are both nonzero, then copy that many of the first
words of X into registers starting with REG, and push the rest of X.
The amount of space pushed is decreased by PARTIAL words,
rounded *down* to a multiple of PARM_BOUNDARY.
REG must be a hard register in this case.
If REG is zero but PARTIAL is not, take any all others actions for an
argument partially in registers, but do not actually load any
registers.
EXTRA is the amount in bytes of extra space to leave next to this arg.
This is ignored if an argument block has already been allocated.
On a machine that lacks real push insns, ARGS_ADDR is the address of
the bottom of the argument block for this call. We use indexing off there
to store the arg. On machines with push insns, ARGS_ADDR is 0 when a
argument block has not been preallocated.
ARGS_SO_FAR is the size of args previously pushed for this call. */
void
emit_push_insn (x, mode, type, size, align, partial, reg, extra,
args_addr, args_so_far)
register rtx x;
enum machine_mode mode;
tree type;
rtx size;
int align;
int partial;
rtx reg;
int extra;
rtx args_addr;
rtx args_so_far;
{
rtx xinner;
enum direction stack_direction
#ifdef STACK_GROWS_DOWNWARD
= downward;
#else
= upward;
#endif
/* Decide where to pad the argument: `downward' for below,
`upward' for above, or `none' for don't pad it.
Default is below for small data on big-endian machines; else above. */
enum direction where_pad = FUNCTION_ARG_PADDING (mode, type);
/* Invert direction if stack is post-update. */
if (STACK_PUSH_CODE == POST_INC || STACK_PUSH_CODE == POST_DEC)
if (where_pad != none)
where_pad = (where_pad == downward ? upward : downward);
xinner = x = protect_from_queue (x, 0);
if (mode == BLKmode)
{
/* Copy a block into the stack, entirely or partially. */
register rtx temp;
int used = partial * UNITS_PER_WORD;
int offset = used % (PARM_BOUNDARY / BITS_PER_UNIT);
int skip;
if (size == 0)
abort ();
used -= offset;
/* USED is now the # of bytes we need not copy to the stack
because registers will take care of them. */
if (partial != 0)
xinner = change_address (xinner, BLKmode,
plus_constant (XEXP (xinner, 0), used));
/* If the partial register-part of the arg counts in its stack size,
skip the part of stack space corresponding to the registers.
Otherwise, start copying to the beginning of the stack space,
by setting SKIP to 0. */
#ifndef REG_PARM_STACK_SPACE
skip = 0;
#else
skip = used;
#endif
#ifdef PUSH_ROUNDING
/* Do it with several push insns if that doesn't take lots of insns
and if there is no difficulty with push insns that skip bytes
on the stack for alignment purposes. */
if (args_addr == 0
&& GET_CODE (size) == CONST_INT
&& skip == 0
&& (move_by_pieces_ninsns ((unsigned) INTVAL (size) - used, align)
< MOVE_RATIO)
/* Here we avoid the case of a structure whose weak alignment
forces many pushes of a small amount of data,
and such small pushes do rounding that causes trouble. */
&& ((! SLOW_UNALIGNED_ACCESS)
|| align >= BIGGEST_ALIGNMENT / BITS_PER_UNIT
|| PUSH_ROUNDING (align) == align)
&& PUSH_ROUNDING (INTVAL (size)) == INTVAL (size))
{
/* Push padding now if padding above and stack grows down,
or if padding below and stack grows up.
But if space already allocated, this has already been done. */
if (extra && args_addr == 0
&& where_pad != none && where_pad != stack_direction)
anti_adjust_stack (GEN_INT (extra));
move_by_pieces (gen_rtx (MEM, BLKmode, gen_push_operand ()), xinner,
INTVAL (size) - used, align);
if (flag_check_memory_usage && ! in_check_memory_usage)
{
rtx temp;
in_check_memory_usage = 1;
temp = get_push_address (INTVAL(size) - used);
if (GET_CODE (x) == MEM && type && AGGREGATE_TYPE_P (type))
emit_library_call (chkr_copy_bitmap_libfunc, 1, VOIDmode, 3,
temp, ptr_mode,
XEXP (xinner, 0), ptr_mode,
GEN_INT (INTVAL(size) - used),
TYPE_MODE (sizetype));
else
emit_library_call (chkr_set_right_libfunc, 1, VOIDmode, 3,
temp, ptr_mode,
GEN_INT (INTVAL(size) - used),
TYPE_MODE (sizetype),
GEN_INT (MEMORY_USE_RW),
TYPE_MODE (integer_type_node));
in_check_memory_usage = 0;
}
}
else
#endif /* PUSH_ROUNDING */
{
/* Otherwise make space on the stack and copy the data
to the address of that space. */
/* Deduct words put into registers from the size we must copy. */
if (partial != 0)
{
if (GET_CODE (size) == CONST_INT)
size = GEN_INT (INTVAL (size) - used);
else
size = expand_binop (GET_MODE (size), sub_optab, size,
GEN_INT (used), NULL_RTX, 0,
OPTAB_LIB_WIDEN);
}
/* Get the address of the stack space.
In this case, we do not deal with EXTRA separately.
A single stack adjust will do. */
if (! args_addr)
{
temp = push_block (size, extra, where_pad == downward);
extra = 0;
}
else if (GET_CODE (args_so_far) == CONST_INT)
temp = memory_address (BLKmode,
plus_constant (args_addr,
skip + INTVAL (args_so_far)));
else
temp = memory_address (BLKmode,
plus_constant (gen_rtx (PLUS, Pmode,
args_addr, args_so_far),
skip));
if (flag_check_memory_usage && ! in_check_memory_usage)
{
rtx target;
in_check_memory_usage = 1;
target = copy_to_reg (temp);
if (GET_CODE (x) == MEM && type && AGGREGATE_TYPE_P (type))
emit_library_call (chkr_copy_bitmap_libfunc, 1, VOIDmode, 3,
target, ptr_mode,
XEXP (xinner, 0), ptr_mode,
size, TYPE_MODE (sizetype));
else
emit_library_call (chkr_set_right_libfunc, 1, VOIDmode, 3,
target, ptr_mode,
size, TYPE_MODE (sizetype),
GEN_INT (MEMORY_USE_RW),
TYPE_MODE (integer_type_node));
in_check_memory_usage = 0;
}
/* TEMP is the address of the block. Copy the data there. */
if (GET_CODE (size) == CONST_INT
&& (move_by_pieces_ninsns ((unsigned) INTVAL (size), align)
< MOVE_RATIO))
{
move_by_pieces (gen_rtx (MEM, BLKmode, temp), xinner,
INTVAL (size), align);
goto ret;
}
/* Try the most limited insn first, because there's no point
including more than one in the machine description unless
the more limited one has some advantage. */
#ifdef HAVE_movstrqi
if (HAVE_movstrqi
&& GET_CODE (size) == CONST_INT
&& ((unsigned) INTVAL (size)
< (1 << (GET_MODE_BITSIZE (QImode) - 1))))
{
rtx pat = gen_movstrqi (gen_rtx (MEM, BLKmode, temp),
xinner, size, GEN_INT (align));
if (pat != 0)
{
emit_insn (pat);
goto ret;
}
}
#endif
#ifdef HAVE_movstrhi
if (HAVE_movstrhi
&& GET_CODE (size) == CONST_INT
&& ((unsigned) INTVAL (size)
< (1 << (GET_MODE_BITSIZE (HImode) - 1))))
{
rtx pat = gen_movstrhi (gen_rtx (MEM, BLKmode, temp),
xinner, size, GEN_INT (align));
if (pat != 0)
{
emit_insn (pat);
goto ret;
}
}
#endif
#ifdef HAVE_movstrsi
if (HAVE_movstrsi)
{
rtx pat = gen_movstrsi (gen_rtx (MEM, BLKmode, temp),
xinner, size, GEN_INT (align));
if (pat != 0)
{
emit_insn (pat);
goto ret;
}
}
#endif
#ifdef HAVE_movstrdi
if (HAVE_movstrdi)
{
rtx pat = gen_movstrdi (gen_rtx (MEM, BLKmode, temp),
xinner, size, GEN_INT (align));
if (pat != 0)
{
emit_insn (pat);
goto ret;
}
}
#endif
#ifndef ACCUMULATE_OUTGOING_ARGS
/* If the source is referenced relative to the stack pointer,
copy it to another register to stabilize it. We do not need
to do this if we know that we won't be changing sp. */
if (reg_mentioned_p (virtual_stack_dynamic_rtx, temp)
|| reg_mentioned_p (virtual_outgoing_args_rtx, temp))
temp = copy_to_reg (temp);
#endif
/* Make inhibit_defer_pop nonzero around the library call
to force it to pop the bcopy-arguments right away. */
NO_DEFER_POP;
#ifdef TARGET_MEM_FUNCTIONS
emit_library_call (memcpy_libfunc, 0,
VOIDmode, 3, temp, Pmode, XEXP (xinner, 0), Pmode,
convert_to_mode (TYPE_MODE (sizetype),
size, TREE_UNSIGNED (sizetype)),
TYPE_MODE (sizetype));
#else
emit_library_call (bcopy_libfunc, 0,
VOIDmode, 3, XEXP (xinner, 0), Pmode, temp, Pmode,
convert_to_mode (TYPE_MODE (integer_type_node),
size,
TREE_UNSIGNED (integer_type_node)),
TYPE_MODE (integer_type_node));
#endif
OK_DEFER_POP;
}
}
else if (partial > 0)
{
/* Scalar partly in registers. */
int size = GET_MODE_SIZE (mode) / UNITS_PER_WORD;
int i;
int not_stack;
/* # words of start of argument
that we must make space for but need not store. */
int offset = partial % (PARM_BOUNDARY / BITS_PER_WORD);
int args_offset = INTVAL (args_so_far);
int skip;
/* Push padding now if padding above and stack grows down,
or if padding below and stack grows up.
But if space already allocated, this has already been done. */
if (extra && args_addr == 0
&& where_pad != none && where_pad != stack_direction)
anti_adjust_stack (GEN_INT (extra));
/* If we make space by pushing it, we might as well push
the real data. Otherwise, we can leave OFFSET nonzero
and leave the space uninitialized. */
if (args_addr == 0)
offset = 0;
/* Now NOT_STACK gets the number of words that we don't need to
allocate on the stack. */
not_stack = partial - offset;
/* If the partial register-part of the arg counts in its stack size,
skip the part of stack space corresponding to the registers.
Otherwise, start copying to the beginning of the stack space,
by setting SKIP to 0. */
#ifndef REG_PARM_STACK_SPACE
skip = 0;
#else
skip = not_stack;
#endif
if (CONSTANT_P (x) && ! LEGITIMATE_CONSTANT_P (x))
x = validize_mem (force_const_mem (mode, x));
/* If X is a hard register in a non-integer mode, copy it into a pseudo;
SUBREGs of such registers are not allowed. */
if ((GET_CODE (x) == REG && REGNO (x) < FIRST_PSEUDO_REGISTER
&& GET_MODE_CLASS (GET_MODE (x)) != MODE_INT))
x = copy_to_reg (x);
/* Loop over all the words allocated on the stack for this arg. */
/* We can do it by words, because any scalar bigger than a word
has a size a multiple of a word. */
#ifndef PUSH_ARGS_REVERSED
for (i = not_stack; i < size; i++)
#else
for (i = size - 1; i >= not_stack; i--)
#endif
if (i >= not_stack + offset)
emit_push_insn (operand_subword_force (x, i, mode),
word_mode, NULL_TREE, NULL_RTX, align, 0, NULL_RTX,
0, args_addr,
GEN_INT (args_offset + ((i - not_stack + skip)
* UNITS_PER_WORD)));
}
else
{
rtx addr;
rtx target = NULL_RTX;
/* Push padding now if padding above and stack grows down,
or if padding below and stack grows up.
But if space already allocated, this has already been done. */
if (extra && args_addr == 0
&& where_pad != none && where_pad != stack_direction)
anti_adjust_stack (GEN_INT (extra));
#ifdef PUSH_ROUNDING
if (args_addr == 0)
addr = gen_push_operand ();
else
#endif
{
if (GET_CODE (args_so_far) == CONST_INT)
addr
= memory_address (mode,
plus_constant (args_addr,
INTVAL (args_so_far)));
else
addr = memory_address (mode, gen_rtx (PLUS, Pmode, args_addr,
args_so_far));
target = addr;
}
emit_move_insn (gen_rtx (MEM, mode, addr), x);
if (flag_check_memory_usage && ! in_check_memory_usage)
{
in_check_memory_usage = 1;
if (target == 0)
target = get_push_address (GET_MODE_SIZE (mode));
if (GET_CODE (x) == MEM && type && AGGREGATE_TYPE_P (type))
emit_library_call (chkr_copy_bitmap_libfunc, 1, VOIDmode, 3,
target, ptr_mode,
XEXP (x, 0), ptr_mode,
GEN_INT (GET_MODE_SIZE (mode)),
TYPE_MODE (sizetype));
else
emit_library_call (chkr_set_right_libfunc, 1, VOIDmode, 3,
target, ptr_mode,
GEN_INT (GET_MODE_SIZE (mode)),
TYPE_MODE (sizetype),
GEN_INT (MEMORY_USE_RW),
TYPE_MODE (integer_type_node));
in_check_memory_usage = 0;
}
}
ret:
/* If part should go in registers, copy that part
into the appropriate registers. Do this now, at the end,
since mem-to-mem copies above may do function calls. */
if (partial > 0 && reg != 0)
{
/* Handle calls that pass values in multiple non-contiguous locations.
The Irix 6 ABI has examples of this. */
if (GET_CODE (reg) == PARALLEL)
emit_group_load (reg, x);
else
move_block_to_reg (REGNO (reg), x, partial, mode);
}
if (extra && args_addr == 0 && where_pad == stack_direction)
anti_adjust_stack (GEN_INT (extra));
}
/* Expand an assignment that stores the value of FROM into TO.
If WANT_VALUE is nonzero, return an rtx for the value of TO.
(This may contain a QUEUED rtx;
if the value is constant, this rtx is a constant.)
Otherwise, the returned value is NULL_RTX.
SUGGEST_REG is no longer actually used.
It used to mean, copy the value through a register
and return that register, if that is possible.
We now use WANT_VALUE to decide whether to do this. */
rtx
expand_assignment (to, from, want_value, suggest_reg)
tree to, from;
int want_value;
int suggest_reg;
{
register rtx to_rtx = 0;
rtx result;
/* Don't crash if the lhs of the assignment was erroneous. */
if (TREE_CODE (to) == ERROR_MARK)
{
result = expand_expr (from, NULL_RTX, VOIDmode, 0);
return want_value ? result : NULL_RTX;
}
if (output_bytecode)
{
tree dest_innermost;
bc_expand_expr (from);
bc_emit_instruction (duplicate);
dest_innermost = bc_expand_address (to);
/* Can't deduce from TYPE that we're dealing with a bitfield, so
take care of it here. */
bc_store_memory (TREE_TYPE (to), dest_innermost);
return NULL;
}
/* Assignment of a structure component needs special treatment
if the structure component's rtx is not simply a MEM.
Assignment of an array element at a constant index, and assignment of
an array element in an unaligned packed structure field, has the same
problem. */
if (TREE_CODE (to) == COMPONENT_REF || TREE_CODE (to) == BIT_FIELD_REF
|| TREE_CODE (to) == ARRAY_REF)
{
enum machine_mode mode1;
int bitsize;
int bitpos;
tree offset;
int unsignedp;
int volatilep = 0;
tree tem;
int alignment;
push_temp_slots ();
tem = get_inner_reference (to, &bitsize, &bitpos, &offset, &mode1,
&unsignedp, &volatilep, &alignment);
/* If we are going to use store_bit_field and extract_bit_field,
make sure to_rtx will be safe for multiple use. */
if (mode1 == VOIDmode && want_value)
tem = stabilize_reference (tem);
to_rtx = expand_expr (tem, NULL_RTX, VOIDmode, EXPAND_MEMORY_USE_DONT);
if (offset != 0)
{
rtx offset_rtx = expand_expr (offset, NULL_RTX, VOIDmode, 0);
if (GET_CODE (to_rtx) != MEM)
abort ();
to_rtx = change_address (to_rtx, VOIDmode,
gen_rtx (PLUS, ptr_mode, XEXP (to_rtx, 0),
force_reg (ptr_mode, offset_rtx)));
}
if (volatilep)
{
if (GET_CODE (to_rtx) == MEM)
{
/* When the offset is zero, to_rtx is the address of the
structure we are storing into, and hence may be shared.
We must make a new MEM before setting the volatile bit. */
if (offset == 0)
to_rtx = copy_rtx (to_rtx);
MEM_VOLATILE_P (to_rtx) = 1;
}
#if 0 /* This was turned off because, when a field is volatile
in an object which is not volatile, the object may be in a register,
and then we would abort over here. */
else
abort ();
#endif
}
if (TREE_CODE (to) == COMPONENT_REF
&& TREE_READONLY (TREE_OPERAND (to, 1)))
{
if (offset = 0)
to_rtx = copy_rtx (to_rtx);
RTX_UNCHANGING_P (to_rtx) = 1;
}
/* Check the access. */
if (flag_check_memory_usage && GET_CODE (to_rtx) == MEM)
{
rtx to_addr;
int size;
int best_mode_size;
enum machine_mode best_mode;
best_mode = get_best_mode (bitsize, bitpos,
TYPE_ALIGN (TREE_TYPE (tem)),
mode1, volatilep);
if (best_mode == VOIDmode)
best_mode = QImode;
best_mode_size = GET_MODE_BITSIZE (best_mode);
to_addr = plus_constant (XEXP (to_rtx, 0), (bitpos / BITS_PER_UNIT));
size = CEIL ((bitpos % best_mode_size) + bitsize, best_mode_size);
size *= GET_MODE_SIZE (best_mode);
/* Check the access right of the pointer. */
if (size)
emit_library_call (chkr_check_addr_libfunc, 1, VOIDmode, 3,
to_addr, ptr_mode,
GEN_INT (size), TYPE_MODE (sizetype),
GEN_INT (MEMORY_USE_WO),
TYPE_MODE (integer_type_node));
}
result = store_field (to_rtx, bitsize, bitpos, mode1, from,
(want_value
/* Spurious cast makes HPUX compiler happy. */
? (enum machine_mode) TYPE_MODE (TREE_TYPE (to))
: VOIDmode),
unsignedp,
/* Required alignment of containing datum. */
alignment,
int_size_in_bytes (TREE_TYPE (tem)));
preserve_temp_slots (result);
free_temp_slots ();
pop_temp_slots ();
/* If the value is meaningful, convert RESULT to the proper mode.
Otherwise, return nothing. */
return (want_value ? convert_modes (TYPE_MODE (TREE_TYPE (to)),
TYPE_MODE (TREE_TYPE (from)),
result,
TREE_UNSIGNED (TREE_TYPE (to)))
: NULL_RTX);
}
/* If the rhs is a function call and its value is not an aggregate,
call the function before we start to compute the lhs.
This is needed for correct code for cases such as
val = setjmp (buf) on machines where reference to val
requires loading up part of an address in a separate insn.
Don't do this if TO is a VAR_DECL whose DECL_RTL is REG since it might be
a promoted variable where the zero- or sign- extension needs to be done.
Handling this in the normal way is safe because no computation is done
before the call. */
if (TREE_CODE (from) == CALL_EXPR && ! aggregate_value_p (from)
&& TREE_CODE (TYPE_SIZE (TREE_TYPE (from))) == INTEGER_CST
&& ! (TREE_CODE (to) == VAR_DECL && GET_CODE (DECL_RTL (to)) == REG))
{
rtx value;
push_temp_slots ();
value = expand_expr (from, NULL_RTX, VOIDmode, 0);
if (to_rtx == 0)
to_rtx = expand_expr (to, NULL_RTX, VOIDmode, EXPAND_MEMORY_USE_WO);
/* Handle calls that return values in multiple non-contiguous locations.
The Irix 6 ABI has examples of this. */
if (GET_CODE (to_rtx) == PARALLEL)
emit_group_load (to_rtx, value);
else if (GET_MODE (to_rtx) == BLKmode)
emit_block_move (to_rtx, value, expr_size (from),
TYPE_ALIGN (TREE_TYPE (from)) / BITS_PER_UNIT);
else
emit_move_insn (to_rtx, value);
preserve_temp_slots (to_rtx);
free_temp_slots ();
pop_temp_slots ();
return want_value ? to_rtx : NULL_RTX;
}
/* Ordinary treatment. Expand TO to get a REG or MEM rtx.
Don't re-expand if it was expanded already (in COMPONENT_REF case). */
if (to_rtx == 0)
to_rtx = expand_expr (to, NULL_RTX, VOIDmode, EXPAND_MEMORY_USE_WO);
/* Don't move directly into a return register. */
if (TREE_CODE (to) == RESULT_DECL && GET_CODE (to_rtx) == REG)
{
rtx temp;
push_temp_slots ();
temp = expand_expr (from, 0, GET_MODE (to_rtx), 0);
emit_move_insn (to_rtx, temp);
preserve_temp_slots (to_rtx);
free_temp_slots ();
pop_temp_slots ();
return want_value ? to_rtx : NULL_RTX;
}
/* In case we are returning the contents of an object which overlaps
the place the value is being stored, use a safe function when copying
a value through a pointer into a structure value return block. */
if (TREE_CODE (to) == RESULT_DECL && TREE_CODE (from) == INDIRECT_REF
&& current_function_returns_struct
&& !current_function_returns_pcc_struct)
{
rtx from_rtx, size;
push_temp_slots ();
size = expr_size (from);
from_rtx = expand_expr (from, NULL_RTX, VOIDmode,
EXPAND_MEMORY_USE_DONT);
/* Copy the rights of the bitmap. */
if (flag_check_memory_usage)
emit_library_call (chkr_copy_bitmap_libfunc, 1, VOIDmode, 3,
XEXP (to_rtx, 0), ptr_mode,
XEXP (from_rtx, 0), ptr_mode,
convert_to_mode (TYPE_MODE (sizetype),
size, TREE_UNSIGNED (sizetype)),
TYPE_MODE (sizetype));
#ifdef TARGET_MEM_FUNCTIONS
emit_library_call (memcpy_libfunc, 0,
VOIDmode, 3, XEXP (to_rtx, 0), Pmode,
XEXP (from_rtx, 0), Pmode,
convert_to_mode (TYPE_MODE (sizetype),
size, TREE_UNSIGNED (sizetype)),
TYPE_MODE (sizetype));
#else
emit_library_call (bcopy_libfunc, 0,
VOIDmode, 3, XEXP (from_rtx, 0), Pmode,
XEXP (to_rtx, 0), Pmode,
convert_to_mode (TYPE_MODE (integer_type_node),
size, TREE_UNSIGNED (integer_type_node)),
TYPE_MODE (integer_type_node));
#endif
preserve_temp_slots (to_rtx);
free_temp_slots ();
pop_temp_slots ();
return want_value ? to_rtx : NULL_RTX;
}
/* Compute FROM and store the value in the rtx we got. */
push_temp_slots ();
result = store_expr (from, to_rtx, want_value);
preserve_temp_slots (result);
free_temp_slots ();
pop_temp_slots ();
return want_value ? result : NULL_RTX;
}
/* Generate code for computing expression EXP,
and storing the value into TARGET.
TARGET may contain a QUEUED rtx.
If WANT_VALUE is nonzero, return a copy of the value