blob: 2ce0e31ef2dd7a008b70015c3efd1cda530ceae4 [file] [log] [blame]
/* Medium-level subroutines: convert bit-field store and extract
and shifts, multiplies and divides to rtl instructions.
Copyright (C) 1987, 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009
Free Software Foundation, Inc.
This file is part of GCC.
GCC is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free
Software Foundation; either version 3, or (at your option) any later
version.
GCC is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
for more details.
You should have received a copy of the GNU General Public License
along with GCC; see the file COPYING3. If not see
<http://www.gnu.org/licenses/>. */
#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "tm.h"
#include "toplev.h"
#include "rtl.h"
#include "tree.h"
#include "tm_p.h"
#include "flags.h"
#include "insn-config.h"
#include "expr.h"
#include "optabs.h"
#include "real.h"
#include "recog.h"
#include "langhooks.h"
#include "df.h"
#include "target.h"
static void store_fixed_bit_field (rtx, unsigned HOST_WIDE_INT,
unsigned HOST_WIDE_INT,
unsigned HOST_WIDE_INT, rtx);
static void store_split_bit_field (rtx, unsigned HOST_WIDE_INT,
unsigned HOST_WIDE_INT, rtx);
static rtx extract_fixed_bit_field (enum machine_mode, rtx,
unsigned HOST_WIDE_INT,
unsigned HOST_WIDE_INT,
unsigned HOST_WIDE_INT, rtx, int);
static rtx mask_rtx (enum machine_mode, int, int, int);
static rtx lshift_value (enum machine_mode, rtx, int, int);
static rtx extract_split_bit_field (rtx, unsigned HOST_WIDE_INT,
unsigned HOST_WIDE_INT, int);
static void do_cmp_and_jump (rtx, rtx, enum rtx_code, enum machine_mode, rtx);
static rtx expand_smod_pow2 (enum machine_mode, rtx, HOST_WIDE_INT);
static rtx expand_sdiv_pow2 (enum machine_mode, rtx, HOST_WIDE_INT);
/* Test whether a value is zero of a power of two. */
#define EXACT_POWER_OF_2_OR_ZERO_P(x) (((x) & ((x) - 1)) == 0)
/* Nonzero means divides or modulus operations are relatively cheap for
powers of two, so don't use branches; emit the operation instead.
Usually, this will mean that the MD file will emit non-branch
sequences. */
static bool sdiv_pow2_cheap[2][NUM_MACHINE_MODES];
static bool smod_pow2_cheap[2][NUM_MACHINE_MODES];
#ifndef SLOW_UNALIGNED_ACCESS
#define SLOW_UNALIGNED_ACCESS(MODE, ALIGN) STRICT_ALIGNMENT
#endif
/* For compilers that support multiple targets with different word sizes,
MAX_BITS_PER_WORD contains the biggest value of BITS_PER_WORD. An example
is the H8/300(H) compiler. */
#ifndef MAX_BITS_PER_WORD
#define MAX_BITS_PER_WORD BITS_PER_WORD
#endif
/* Reduce conditional compilation elsewhere. */
#ifndef HAVE_insv
#define HAVE_insv 0
#define CODE_FOR_insv CODE_FOR_nothing
#define gen_insv(a,b,c,d) NULL_RTX
#endif
#ifndef HAVE_extv
#define HAVE_extv 0
#define CODE_FOR_extv CODE_FOR_nothing
#define gen_extv(a,b,c,d) NULL_RTX
#endif
#ifndef HAVE_extzv
#define HAVE_extzv 0
#define CODE_FOR_extzv CODE_FOR_nothing
#define gen_extzv(a,b,c,d) NULL_RTX
#endif
/* Cost of various pieces of RTL. Note that some of these are indexed by
shift count and some by mode. */
static int zero_cost[2];
static int add_cost[2][NUM_MACHINE_MODES];
static int neg_cost[2][NUM_MACHINE_MODES];
static int shift_cost[2][NUM_MACHINE_MODES][MAX_BITS_PER_WORD];
static int shiftadd_cost[2][NUM_MACHINE_MODES][MAX_BITS_PER_WORD];
static int shiftsub_cost[2][NUM_MACHINE_MODES][MAX_BITS_PER_WORD];
static int mul_cost[2][NUM_MACHINE_MODES];
static int sdiv_cost[2][NUM_MACHINE_MODES];
static int udiv_cost[2][NUM_MACHINE_MODES];
static int mul_widen_cost[2][NUM_MACHINE_MODES];
static int mul_highpart_cost[2][NUM_MACHINE_MODES];
void
init_expmed (void)
{
struct
{
struct rtx_def reg; rtunion reg_fld[2];
struct rtx_def plus; rtunion plus_fld1;
struct rtx_def neg;
struct rtx_def mult; rtunion mult_fld1;
struct rtx_def sdiv; rtunion sdiv_fld1;
struct rtx_def udiv; rtunion udiv_fld1;
struct rtx_def zext;
struct rtx_def sdiv_32; rtunion sdiv_32_fld1;
struct rtx_def smod_32; rtunion smod_32_fld1;
struct rtx_def wide_mult; rtunion wide_mult_fld1;
struct rtx_def wide_lshr; rtunion wide_lshr_fld1;
struct rtx_def wide_trunc;
struct rtx_def shift; rtunion shift_fld1;
struct rtx_def shift_mult; rtunion shift_mult_fld1;
struct rtx_def shift_add; rtunion shift_add_fld1;
struct rtx_def shift_sub; rtunion shift_sub_fld1;
} all;
rtx pow2[MAX_BITS_PER_WORD];
rtx cint[MAX_BITS_PER_WORD];
int m, n;
enum machine_mode mode, wider_mode;
int speed;
for (m = 1; m < MAX_BITS_PER_WORD; m++)
{
pow2[m] = GEN_INT ((HOST_WIDE_INT) 1 << m);
cint[m] = GEN_INT (m);
}
memset (&all, 0, sizeof all);
PUT_CODE (&all.reg, REG);
/* Avoid using hard regs in ways which may be unsupported. */
SET_REGNO (&all.reg, LAST_VIRTUAL_REGISTER + 1);
PUT_CODE (&all.plus, PLUS);
XEXP (&all.plus, 0) = &all.reg;
XEXP (&all.plus, 1) = &all.reg;
PUT_CODE (&all.neg, NEG);
XEXP (&all.neg, 0) = &all.reg;
PUT_CODE (&all.mult, MULT);
XEXP (&all.mult, 0) = &all.reg;
XEXP (&all.mult, 1) = &all.reg;
PUT_CODE (&all.sdiv, DIV);
XEXP (&all.sdiv, 0) = &all.reg;
XEXP (&all.sdiv, 1) = &all.reg;
PUT_CODE (&all.udiv, UDIV);
XEXP (&all.udiv, 0) = &all.reg;
XEXP (&all.udiv, 1) = &all.reg;
PUT_CODE (&all.sdiv_32, DIV);
XEXP (&all.sdiv_32, 0) = &all.reg;
XEXP (&all.sdiv_32, 1) = 32 < MAX_BITS_PER_WORD ? cint[32] : GEN_INT (32);
PUT_CODE (&all.smod_32, MOD);
XEXP (&all.smod_32, 0) = &all.reg;
XEXP (&all.smod_32, 1) = XEXP (&all.sdiv_32, 1);
PUT_CODE (&all.zext, ZERO_EXTEND);
XEXP (&all.zext, 0) = &all.reg;
PUT_CODE (&all.wide_mult, MULT);
XEXP (&all.wide_mult, 0) = &all.zext;
XEXP (&all.wide_mult, 1) = &all.zext;
PUT_CODE (&all.wide_lshr, LSHIFTRT);
XEXP (&all.wide_lshr, 0) = &all.wide_mult;
PUT_CODE (&all.wide_trunc, TRUNCATE);
XEXP (&all.wide_trunc, 0) = &all.wide_lshr;
PUT_CODE (&all.shift, ASHIFT);
XEXP (&all.shift, 0) = &all.reg;
PUT_CODE (&all.shift_mult, MULT);
XEXP (&all.shift_mult, 0) = &all.reg;
PUT_CODE (&all.shift_add, PLUS);
XEXP (&all.shift_add, 0) = &all.shift_mult;
XEXP (&all.shift_add, 1) = &all.reg;
PUT_CODE (&all.shift_sub, MINUS);
XEXP (&all.shift_sub, 0) = &all.shift_mult;
XEXP (&all.shift_sub, 1) = &all.reg;
for (speed = 0; speed < 2; speed++)
{
crtl->maybe_hot_insn_p = speed;
zero_cost[speed] = rtx_cost (const0_rtx, 0, speed);
for (mode = GET_CLASS_NARROWEST_MODE (MODE_INT);
mode != VOIDmode;
mode = GET_MODE_WIDER_MODE (mode))
{
PUT_MODE (&all.reg, mode);
PUT_MODE (&all.plus, mode);
PUT_MODE (&all.neg, mode);
PUT_MODE (&all.mult, mode);
PUT_MODE (&all.sdiv, mode);
PUT_MODE (&all.udiv, mode);
PUT_MODE (&all.sdiv_32, mode);
PUT_MODE (&all.smod_32, mode);
PUT_MODE (&all.wide_trunc, mode);
PUT_MODE (&all.shift, mode);
PUT_MODE (&all.shift_mult, mode);
PUT_MODE (&all.shift_add, mode);
PUT_MODE (&all.shift_sub, mode);
add_cost[speed][mode] = rtx_cost (&all.plus, SET, speed);
neg_cost[speed][mode] = rtx_cost (&all.neg, SET, speed);
mul_cost[speed][mode] = rtx_cost (&all.mult, SET, speed);
sdiv_cost[speed][mode] = rtx_cost (&all.sdiv, SET, speed);
udiv_cost[speed][mode] = rtx_cost (&all.udiv, SET, speed);
sdiv_pow2_cheap[speed][mode] = (rtx_cost (&all.sdiv_32, SET, speed)
<= 2 * add_cost[speed][mode]);
smod_pow2_cheap[speed][mode] = (rtx_cost (&all.smod_32, SET, speed)
<= 4 * add_cost[speed][mode]);
wider_mode = GET_MODE_WIDER_MODE (mode);
if (wider_mode != VOIDmode)
{
PUT_MODE (&all.zext, wider_mode);
PUT_MODE (&all.wide_mult, wider_mode);
PUT_MODE (&all.wide_lshr, wider_mode);
XEXP (&all.wide_lshr, 1) = GEN_INT (GET_MODE_BITSIZE (mode));
mul_widen_cost[speed][wider_mode]
= rtx_cost (&all.wide_mult, SET, speed);
mul_highpart_cost[speed][mode]
= rtx_cost (&all.wide_trunc, SET, speed);
}
shift_cost[speed][mode][0] = 0;
shiftadd_cost[speed][mode][0] = shiftsub_cost[speed][mode][0]
= add_cost[speed][mode];
n = MIN (MAX_BITS_PER_WORD, GET_MODE_BITSIZE (mode));
for (m = 1; m < n; m++)
{
XEXP (&all.shift, 1) = cint[m];
XEXP (&all.shift_mult, 1) = pow2[m];
shift_cost[speed][mode][m] = rtx_cost (&all.shift, SET, speed);
shiftadd_cost[speed][mode][m] = rtx_cost (&all.shift_add, SET, speed);
shiftsub_cost[speed][mode][m] = rtx_cost (&all.shift_sub, SET, speed);
}
}
}
default_rtl_profile ();
}
/* Return an rtx representing minus the value of X.
MODE is the intended mode of the result,
useful if X is a CONST_INT. */
rtx
negate_rtx (enum machine_mode mode, rtx x)
{
rtx result = simplify_unary_operation (NEG, mode, x, mode);
if (result == 0)
result = expand_unop (mode, neg_optab, x, NULL_RTX, 0);
return result;
}
/* Report on the availability of insv/extv/extzv and the desired mode
of each of their operands. Returns MAX_MACHINE_MODE if HAVE_foo
is false; else the mode of the specified operand. If OPNO is -1,
all the caller cares about is whether the insn is available. */
enum machine_mode
mode_for_extraction (enum extraction_pattern pattern, int opno)
{
const struct insn_data *data;
switch (pattern)
{
case EP_insv:
if (HAVE_insv)
{
data = &insn_data[CODE_FOR_insv];
break;
}
return MAX_MACHINE_MODE;
case EP_extv:
if (HAVE_extv)
{
data = &insn_data[CODE_FOR_extv];
break;
}
return MAX_MACHINE_MODE;
case EP_extzv:
if (HAVE_extzv)
{
data = &insn_data[CODE_FOR_extzv];
break;
}
return MAX_MACHINE_MODE;
default:
gcc_unreachable ();
}
if (opno == -1)
return VOIDmode;
/* Everyone who uses this function used to follow it with
if (result == VOIDmode) result = word_mode; */
if (data->operand[opno].mode == VOIDmode)
return word_mode;
return data->operand[opno].mode;
}
/* Return true if X, of mode MODE, matches the predicate for operand
OPNO of instruction ICODE. Allow volatile memories, regardless of
the ambient volatile_ok setting. */
static bool
check_predicate_volatile_ok (enum insn_code icode, int opno,
rtx x, enum machine_mode mode)
{
bool save_volatile_ok, result;
save_volatile_ok = volatile_ok;
result = insn_data[(int) icode].operand[opno].predicate (x, mode);
volatile_ok = save_volatile_ok;
return result;
}
/* A subroutine of store_bit_field, with the same arguments. Return true
if the operation could be implemented.
If FALLBACK_P is true, fall back to store_fixed_bit_field if we have
no other way of implementing the operation. If FALLBACK_P is false,
return false instead. */
static bool
store_bit_field_1 (rtx str_rtx, unsigned HOST_WIDE_INT bitsize,
unsigned HOST_WIDE_INT bitnum, enum machine_mode fieldmode,
rtx value, bool fallback_p)
{
unsigned int unit
= (MEM_P (str_rtx)) ? BITS_PER_UNIT : BITS_PER_WORD;
unsigned HOST_WIDE_INT offset, bitpos;
rtx op0 = str_rtx;
int byte_offset;
rtx orig_value;
enum machine_mode op_mode = mode_for_extraction (EP_insv, 3);
while (GET_CODE (op0) == SUBREG)
{
/* The following line once was done only if WORDS_BIG_ENDIAN,
but I think that is a mistake. WORDS_BIG_ENDIAN is
meaningful at a much higher level; when structures are copied
between memory and regs, the higher-numbered regs
always get higher addresses. */
int inner_mode_size = GET_MODE_SIZE (GET_MODE (SUBREG_REG (op0)));
int outer_mode_size = GET_MODE_SIZE (GET_MODE (op0));
byte_offset = 0;
/* Paradoxical subregs need special handling on big endian machines. */
if (SUBREG_BYTE (op0) == 0 && inner_mode_size < outer_mode_size)
{
int difference = inner_mode_size - outer_mode_size;
if (WORDS_BIG_ENDIAN)
byte_offset += (difference / UNITS_PER_WORD) * UNITS_PER_WORD;
if (BYTES_BIG_ENDIAN)
byte_offset += difference % UNITS_PER_WORD;
}
else
byte_offset = SUBREG_BYTE (op0);
bitnum += byte_offset * BITS_PER_UNIT;
op0 = SUBREG_REG (op0);
}
/* No action is needed if the target is a register and if the field
lies completely outside that register. This can occur if the source
code contains an out-of-bounds access to a small array. */
if (REG_P (op0) && bitnum >= GET_MODE_BITSIZE (GET_MODE (op0)))
return true;
/* Use vec_set patterns for inserting parts of vectors whenever
available. */
if (VECTOR_MODE_P (GET_MODE (op0))
&& !MEM_P (op0)
&& (optab_handler (vec_set_optab, GET_MODE (op0))->insn_code
!= CODE_FOR_nothing)
&& fieldmode == GET_MODE_INNER (GET_MODE (op0))
&& bitsize == GET_MODE_BITSIZE (GET_MODE_INNER (GET_MODE (op0)))
&& !(bitnum % GET_MODE_BITSIZE (GET_MODE_INNER (GET_MODE (op0)))))
{
enum machine_mode outermode = GET_MODE (op0);
enum machine_mode innermode = GET_MODE_INNER (outermode);
int icode = (int) optab_handler (vec_set_optab, outermode)->insn_code;
int pos = bitnum / GET_MODE_BITSIZE (innermode);
rtx rtxpos = GEN_INT (pos);
rtx src = value;
rtx dest = op0;
rtx pat, seq;
enum machine_mode mode0 = insn_data[icode].operand[0].mode;
enum machine_mode mode1 = insn_data[icode].operand[1].mode;
enum machine_mode mode2 = insn_data[icode].operand[2].mode;
start_sequence ();
if (! (*insn_data[icode].operand[1].predicate) (src, mode1))
src = copy_to_mode_reg (mode1, src);
if (! (*insn_data[icode].operand[2].predicate) (rtxpos, mode2))
rtxpos = copy_to_mode_reg (mode1, rtxpos);
/* We could handle this, but we should always be called with a pseudo
for our targets and all insns should take them as outputs. */
gcc_assert ((*insn_data[icode].operand[0].predicate) (dest, mode0)
&& (*insn_data[icode].operand[1].predicate) (src, mode1)
&& (*insn_data[icode].operand[2].predicate) (rtxpos, mode2));
pat = GEN_FCN (icode) (dest, src, rtxpos);
seq = get_insns ();
end_sequence ();
if (pat)
{
emit_insn (seq);
emit_insn (pat);
return true;
}
}
/* If the target is a register, overwriting the entire object, or storing
a full-word or multi-word field can be done with just a SUBREG.
If the target is memory, storing any naturally aligned field can be
done with a simple store. For targets that support fast unaligned
memory, any naturally sized, unit aligned field can be done directly. */
offset = bitnum / unit;
bitpos = bitnum % unit;
byte_offset = (bitnum % BITS_PER_WORD) / BITS_PER_UNIT
+ (offset * UNITS_PER_WORD);
if (bitpos == 0
&& bitsize == GET_MODE_BITSIZE (fieldmode)
&& (!MEM_P (op0)
? ((GET_MODE_SIZE (fieldmode) >= UNITS_PER_WORD
|| GET_MODE_SIZE (GET_MODE (op0)) == GET_MODE_SIZE (fieldmode))
&& byte_offset % GET_MODE_SIZE (fieldmode) == 0)
: (! SLOW_UNALIGNED_ACCESS (fieldmode, MEM_ALIGN (op0))
|| (offset * BITS_PER_UNIT % bitsize == 0
&& MEM_ALIGN (op0) % GET_MODE_BITSIZE (fieldmode) == 0))))
{
if (MEM_P (op0))
op0 = adjust_address (op0, fieldmode, offset);
else if (GET_MODE (op0) != fieldmode)
op0 = simplify_gen_subreg (fieldmode, op0, GET_MODE (op0),
byte_offset);
emit_move_insn (op0, value);
return true;
}
/* Make sure we are playing with integral modes. Pun with subregs
if we aren't. This must come after the entire register case above,
since that case is valid for any mode. The following cases are only
valid for integral modes. */
{
enum machine_mode imode = int_mode_for_mode (GET_MODE (op0));
if (imode != GET_MODE (op0))
{
if (MEM_P (op0))
op0 = adjust_address (op0, imode, 0);
else
{
gcc_assert (imode != BLKmode);
op0 = gen_lowpart (imode, op0);
}
}
}
/* We may be accessing data outside the field, which means
we can alias adjacent data. */
if (MEM_P (op0))
{
op0 = shallow_copy_rtx (op0);
set_mem_alias_set (op0, 0);
set_mem_expr (op0, 0);
}
/* If OP0 is a register, BITPOS must count within a word.
But as we have it, it counts within whatever size OP0 now has.
On a bigendian machine, these are not the same, so convert. */
if (BYTES_BIG_ENDIAN
&& !MEM_P (op0)
&& unit > GET_MODE_BITSIZE (GET_MODE (op0)))
bitpos += unit - GET_MODE_BITSIZE (GET_MODE (op0));
/* Storing an lsb-aligned field in a register
can be done with a movestrict instruction. */
if (!MEM_P (op0)
&& (BYTES_BIG_ENDIAN ? bitpos + bitsize == unit : bitpos == 0)
&& bitsize == GET_MODE_BITSIZE (fieldmode)
&& (optab_handler (movstrict_optab, fieldmode)->insn_code
!= CODE_FOR_nothing))
{
int icode = optab_handler (movstrict_optab, fieldmode)->insn_code;
rtx insn;
rtx start = get_last_insn ();
rtx arg0 = op0;
/* Get appropriate low part of the value being stored. */
if (GET_CODE (value) == CONST_INT || REG_P (value))
value = gen_lowpart (fieldmode, value);
else if (!(GET_CODE (value) == SYMBOL_REF
|| GET_CODE (value) == LABEL_REF
|| GET_CODE (value) == CONST))
value = convert_to_mode (fieldmode, value, 0);
if (! (*insn_data[icode].operand[1].predicate) (value, fieldmode))
value = copy_to_mode_reg (fieldmode, value);
if (GET_CODE (op0) == SUBREG)
{
/* Else we've got some float mode source being extracted into
a different float mode destination -- this combination of
subregs results in Severe Tire Damage. */
gcc_assert (GET_MODE (SUBREG_REG (op0)) == fieldmode
|| GET_MODE_CLASS (fieldmode) == MODE_INT
|| GET_MODE_CLASS (fieldmode) == MODE_PARTIAL_INT);
arg0 = SUBREG_REG (op0);
}
insn = (GEN_FCN (icode)
(gen_rtx_SUBREG (fieldmode, arg0,
(bitnum % BITS_PER_WORD) / BITS_PER_UNIT
+ (offset * UNITS_PER_WORD)),
value));
if (insn)
{
emit_insn (insn);
return true;
}
delete_insns_since (start);
}
/* Handle fields bigger than a word. */
if (bitsize > BITS_PER_WORD)
{
/* Here we transfer the words of the field
in the order least significant first.
This is because the most significant word is the one which may
be less than full.
However, only do that if the value is not BLKmode. */
unsigned int backwards = WORDS_BIG_ENDIAN && fieldmode != BLKmode;
unsigned int nwords = (bitsize + (BITS_PER_WORD - 1)) / BITS_PER_WORD;
unsigned int i;
rtx last;
/* This is the mode we must force value to, so that there will be enough
subwords to extract. Note that fieldmode will often (always?) be
VOIDmode, because that is what store_field uses to indicate that this
is a bit field, but passing VOIDmode to operand_subword_force
is not allowed. */
fieldmode = GET_MODE (value);
if (fieldmode == VOIDmode)
fieldmode = smallest_mode_for_size (nwords * BITS_PER_WORD, MODE_INT);
last = get_last_insn ();
for (i = 0; i < nwords; i++)
{
/* If I is 0, use the low-order word in both field and target;
if I is 1, use the next to lowest word; and so on. */
unsigned int wordnum = (backwards ? nwords - i - 1 : i);
unsigned int bit_offset = (backwards
? MAX ((int) bitsize - ((int) i + 1)
* BITS_PER_WORD,
0)
: (int) i * BITS_PER_WORD);
rtx value_word = operand_subword_force (value, wordnum, fieldmode);
if (!store_bit_field_1 (op0, MIN (BITS_PER_WORD,
bitsize - i * BITS_PER_WORD),
bitnum + bit_offset, word_mode,
value_word, fallback_p))
{
delete_insns_since (last);
return false;
}
}
return true;
}
/* From here on we can assume that the field to be stored in is
a full-word (whatever type that is), since it is shorter than a word. */
/* OFFSET is the number of words or bytes (UNIT says which)
from STR_RTX to the first word or byte containing part of the field. */
if (!MEM_P (op0))
{
if (offset != 0
|| GET_MODE_SIZE (GET_MODE (op0)) > UNITS_PER_WORD)
{
if (!REG_P (op0))
{
/* Since this is a destination (lvalue), we can't copy
it to a pseudo. We can remove a SUBREG that does not
change the size of the operand. Such a SUBREG may
have been added above. */
gcc_assert (GET_CODE (op0) == SUBREG
&& (GET_MODE_SIZE (GET_MODE (op0))
== GET_MODE_SIZE (GET_MODE (SUBREG_REG (op0)))));
op0 = SUBREG_REG (op0);
}
op0 = gen_rtx_SUBREG (mode_for_size (BITS_PER_WORD, MODE_INT, 0),
op0, (offset * UNITS_PER_WORD));
}
offset = 0;
}
/* If VALUE has a floating-point or complex mode, access it as an
integer of the corresponding size. This can occur on a machine
with 64 bit registers that uses SFmode for float. It can also
occur for unaligned float or complex fields. */
orig_value = value;
if (GET_MODE (value) != VOIDmode
&& GET_MODE_CLASS (GET_MODE (value)) != MODE_INT
&& GET_MODE_CLASS (GET_MODE (value)) != MODE_PARTIAL_INT)
{
value = gen_reg_rtx (int_mode_for_mode (GET_MODE (value)));
emit_move_insn (gen_lowpart (GET_MODE (orig_value), value), orig_value);
}
/* Now OFFSET is nonzero only if OP0 is memory
and is therefore always measured in bytes. */
if (HAVE_insv
&& GET_MODE (value) != BLKmode
&& bitsize > 0
&& GET_MODE_BITSIZE (op_mode) >= bitsize
&& ! ((REG_P (op0) || GET_CODE (op0) == SUBREG)
&& (bitsize + bitpos > GET_MODE_BITSIZE (op_mode)))
&& insn_data[CODE_FOR_insv].operand[1].predicate (GEN_INT (bitsize),
VOIDmode)
&& check_predicate_volatile_ok (CODE_FOR_insv, 0, op0, VOIDmode))
{
int xbitpos = bitpos;
rtx value1;
rtx xop0 = op0;
rtx last = get_last_insn ();
rtx pat;
/* Add OFFSET into OP0's address. */
if (MEM_P (xop0))
xop0 = adjust_address (xop0, byte_mode, offset);
/* If xop0 is a register, we need it in OP_MODE
to make it acceptable to the format of insv. */
if (GET_CODE (xop0) == SUBREG)
/* We can't just change the mode, because this might clobber op0,
and we will need the original value of op0 if insv fails. */
xop0 = gen_rtx_SUBREG (op_mode, SUBREG_REG (xop0), SUBREG_BYTE (xop0));
if (REG_P (xop0) && GET_MODE (xop0) != op_mode)
xop0 = gen_rtx_SUBREG (op_mode, xop0, 0);
/* On big-endian machines, we count bits from the most significant.
If the bit field insn does not, we must invert. */
if (BITS_BIG_ENDIAN != BYTES_BIG_ENDIAN)
xbitpos = unit - bitsize - xbitpos;
/* We have been counting XBITPOS within UNIT.
Count instead within the size of the register. */
if (BITS_BIG_ENDIAN && !MEM_P (xop0))
xbitpos += GET_MODE_BITSIZE (op_mode) - unit;
unit = GET_MODE_BITSIZE (op_mode);
/* Convert VALUE to op_mode (which insv insn wants) in VALUE1. */
value1 = value;
if (GET_MODE (value) != op_mode)
{
if (GET_MODE_BITSIZE (GET_MODE (value)) >= bitsize)
{
/* Optimization: Don't bother really extending VALUE
if it has all the bits we will actually use. However,
if we must narrow it, be sure we do it correctly. */
if (GET_MODE_SIZE (GET_MODE (value)) < GET_MODE_SIZE (op_mode))
{
rtx tmp;
tmp = simplify_subreg (op_mode, value1, GET_MODE (value), 0);
if (! tmp)
tmp = simplify_gen_subreg (op_mode,
force_reg (GET_MODE (value),
value1),
GET_MODE (value), 0);
value1 = tmp;
}
else
value1 = gen_lowpart (op_mode, value1);
}
else if (GET_CODE (value) == CONST_INT)
value1 = gen_int_mode (INTVAL (value), op_mode);
else
/* Parse phase is supposed to make VALUE's data type
match that of the component reference, which is a type
at least as wide as the field; so VALUE should have
a mode that corresponds to that type. */
gcc_assert (CONSTANT_P (value));
}
/* If this machine's insv insists on a register,
get VALUE1 into a register. */
if (! ((*insn_data[(int) CODE_FOR_insv].operand[3].predicate)
(value1, op_mode)))
value1 = force_reg (op_mode, value1);
pat = gen_insv (xop0, GEN_INT (bitsize), GEN_INT (xbitpos), value1);
if (pat)
{
emit_insn (pat);
/* If the mode of the insertion is wider than the mode of the
target register we created a paradoxical subreg for the
target. Truncate the paradoxical subreg of the target to
itself properly. */
if (!TRULY_NOOP_TRUNCATION (GET_MODE_BITSIZE (GET_MODE (op0)),
GET_MODE_BITSIZE (op_mode))
&& (REG_P (xop0)
|| GET_CODE (xop0) == SUBREG))
convert_move (op0, xop0, true);
return true;
}
delete_insns_since (last);
}
/* If OP0 is a memory, try copying it to a register and seeing if a
cheap register alternative is available. */
if (HAVE_insv && MEM_P (op0))
{
enum machine_mode bestmode;
/* Get the mode to use for inserting into this field. If OP0 is
BLKmode, get the smallest mode consistent with the alignment. If
OP0 is a non-BLKmode object that is no wider than OP_MODE, use its
mode. Otherwise, use the smallest mode containing the field. */
if (GET_MODE (op0) == BLKmode
|| (op_mode != MAX_MACHINE_MODE
&& GET_MODE_SIZE (GET_MODE (op0)) > GET_MODE_SIZE (op_mode)))
bestmode = get_best_mode (bitsize, bitnum, MEM_ALIGN (op0),
(op_mode == MAX_MACHINE_MODE
? VOIDmode : op_mode),
MEM_VOLATILE_P (op0));
else
bestmode = GET_MODE (op0);
if (bestmode != VOIDmode
&& GET_MODE_SIZE (bestmode) >= GET_MODE_SIZE (fieldmode)
&& !(SLOW_UNALIGNED_ACCESS (bestmode, MEM_ALIGN (op0))
&& GET_MODE_BITSIZE (bestmode) > MEM_ALIGN (op0)))
{
rtx last, tempreg, xop0;
unsigned HOST_WIDE_INT xoffset, xbitpos;
last = get_last_insn ();
/* Adjust address to point to the containing unit of
that mode. Compute the offset as a multiple of this unit,
counting in bytes. */
unit = GET_MODE_BITSIZE (bestmode);
xoffset = (bitnum / unit) * GET_MODE_SIZE (bestmode);
xbitpos = bitnum % unit;
xop0 = adjust_address (op0, bestmode, xoffset);
/* Fetch that unit, store the bitfield in it, then store
the unit. */
tempreg = copy_to_reg (xop0);
if (store_bit_field_1 (tempreg, bitsize, xbitpos,
fieldmode, orig_value, false))
{
emit_move_insn (xop0, tempreg);
return true;
}
delete_insns_since (last);
}
}
if (!fallback_p)
return false;
store_fixed_bit_field (op0, offset, bitsize, bitpos, value);
return true;
}
/* Generate code to store value from rtx VALUE
into a bit-field within structure STR_RTX
containing BITSIZE bits starting at bit BITNUM.
FIELDMODE is the machine-mode of the FIELD_DECL node for this field. */
void
store_bit_field (rtx str_rtx, unsigned HOST_WIDE_INT bitsize,
unsigned HOST_WIDE_INT bitnum, enum machine_mode fieldmode,
rtx value)
{
if (!store_bit_field_1 (str_rtx, bitsize, bitnum, fieldmode, value, true))
gcc_unreachable ();
}
/* Use shifts and boolean operations to store VALUE
into a bit field of width BITSIZE
in a memory location specified by OP0 except offset by OFFSET bytes.
(OFFSET must be 0 if OP0 is a register.)
The field starts at position BITPOS within the byte.
(If OP0 is a register, it may be a full word or a narrower mode,
but BITPOS still counts within a full word,
which is significant on bigendian machines.) */
static void
store_fixed_bit_field (rtx op0, unsigned HOST_WIDE_INT offset,
unsigned HOST_WIDE_INT bitsize,
unsigned HOST_WIDE_INT bitpos, rtx value)
{
enum machine_mode mode;
unsigned int total_bits = BITS_PER_WORD;
rtx temp;
int all_zero = 0;
int all_one = 0;
/* There is a case not handled here:
a structure with a known alignment of just a halfword
and a field split across two aligned halfwords within the structure.
Or likewise a structure with a known alignment of just a byte
and a field split across two bytes.
Such cases are not supposed to be able to occur. */
if (REG_P (op0) || GET_CODE (op0) == SUBREG)
{
gcc_assert (!offset);
/* Special treatment for a bit field split across two registers. */
if (bitsize + bitpos > BITS_PER_WORD)
{
store_split_bit_field (op0, bitsize, bitpos, value);
return;
}
}
else
{
/* Get the proper mode to use for this field. We want a mode that
includes the entire field. If such a mode would be larger than
a word, we won't be doing the extraction the normal way.
We don't want a mode bigger than the destination. */
mode = GET_MODE (op0);
if (GET_MODE_BITSIZE (mode) == 0
|| GET_MODE_BITSIZE (mode) > GET_MODE_BITSIZE (word_mode))
mode = word_mode;
mode = get_best_mode (bitsize, bitpos + offset * BITS_PER_UNIT,
MEM_ALIGN (op0), mode, MEM_VOLATILE_P (op0));
if (mode == VOIDmode)
{
/* The only way this should occur is if the field spans word
boundaries. */
store_split_bit_field (op0, bitsize, bitpos + offset * BITS_PER_UNIT,
value);
return;
}
total_bits = GET_MODE_BITSIZE (mode);
/* Make sure bitpos is valid for the chosen mode. Adjust BITPOS to
be in the range 0 to total_bits-1, and put any excess bytes in
OFFSET. */
if (bitpos >= total_bits)
{
offset += (bitpos / total_bits) * (total_bits / BITS_PER_UNIT);
bitpos -= ((bitpos / total_bits) * (total_bits / BITS_PER_UNIT)
* BITS_PER_UNIT);
}
/* Get ref to an aligned byte, halfword, or word containing the field.
Adjust BITPOS to be position within a word,
and OFFSET to be the offset of that word.
Then alter OP0 to refer to that word. */
bitpos += (offset % (total_bits / BITS_PER_UNIT)) * BITS_PER_UNIT;
offset -= (offset % (total_bits / BITS_PER_UNIT));
op0 = adjust_address (op0, mode, offset);
}
mode = GET_MODE (op0);
/* Now MODE is either some integral mode for a MEM as OP0,
or is a full-word for a REG as OP0. TOTAL_BITS corresponds.
The bit field is contained entirely within OP0.
BITPOS is the starting bit number within OP0.
(OP0's mode may actually be narrower than MODE.) */
if (BYTES_BIG_ENDIAN)
/* BITPOS is the distance between our msb
and that of the containing datum.
Convert it to the distance from the lsb. */
bitpos = total_bits - bitsize - bitpos;
/* Now BITPOS is always the distance between our lsb
and that of OP0. */
/* Shift VALUE left by BITPOS bits. If VALUE is not constant,
we must first convert its mode to MODE. */
if (GET_CODE (value) == CONST_INT)
{
HOST_WIDE_INT v = INTVAL (value);
if (bitsize < HOST_BITS_PER_WIDE_INT)
v &= ((HOST_WIDE_INT) 1 << bitsize) - 1;
if (v == 0)
all_zero = 1;
else if ((bitsize < HOST_BITS_PER_WIDE_INT
&& v == ((HOST_WIDE_INT) 1 << bitsize) - 1)
|| (bitsize == HOST_BITS_PER_WIDE_INT && v == -1))
all_one = 1;
value = lshift_value (mode, value, bitpos, bitsize);
}
else
{
int must_and = (GET_MODE_BITSIZE (GET_MODE (value)) != bitsize
&& bitpos + bitsize != GET_MODE_BITSIZE (mode));
if (GET_MODE (value) != mode)
value = convert_to_mode (mode, value, 1);
if (must_and)
value = expand_binop (mode, and_optab, value,
mask_rtx (mode, 0, bitsize, 0),
NULL_RTX, 1, OPTAB_LIB_WIDEN);
if (bitpos > 0)
value = expand_shift (LSHIFT_EXPR, mode, value,
build_int_cst (NULL_TREE, bitpos), NULL_RTX, 1);
}
/* Now clear the chosen bits in OP0,
except that if VALUE is -1 we need not bother. */
/* We keep the intermediates in registers to allow CSE to combine
consecutive bitfield assignments. */
temp = force_reg (mode, op0);
if (! all_one)
{
temp = expand_binop (mode, and_optab, temp,
mask_rtx (mode, bitpos, bitsize, 1),
NULL_RTX, 1, OPTAB_LIB_WIDEN);
temp = force_reg (mode, temp);
}
/* Now logical-or VALUE into OP0, unless it is zero. */
if (! all_zero)
{
temp = expand_binop (mode, ior_optab, temp, value,
NULL_RTX, 1, OPTAB_LIB_WIDEN);
temp = force_reg (mode, temp);
}
if (op0 != temp)
{
op0 = copy_rtx (op0);
emit_move_insn (op0, temp);
}
}
/* Store a bit field that is split across multiple accessible memory objects.
OP0 is the REG, SUBREG or MEM rtx for the first of the objects.
BITSIZE is the field width; BITPOS the position of its first bit
(within the word).
VALUE is the value to store.
This does not yet handle fields wider than BITS_PER_WORD. */
static void
store_split_bit_field (rtx op0, unsigned HOST_WIDE_INT bitsize,
unsigned HOST_WIDE_INT bitpos, rtx value)
{
unsigned int unit;
unsigned int bitsdone = 0;
/* Make sure UNIT isn't larger than BITS_PER_WORD, we can only handle that
much at a time. */
if (REG_P (op0) || GET_CODE (op0) == SUBREG)
unit = BITS_PER_WORD;
else
unit = MIN (MEM_ALIGN (op0), BITS_PER_WORD);
/* If VALUE is a constant other than a CONST_INT, get it into a register in
WORD_MODE. If we can do this using gen_lowpart_common, do so. Note
that VALUE might be a floating-point constant. */
if (CONSTANT_P (value) && GET_CODE (value) != CONST_INT)
{
rtx word = gen_lowpart_common (word_mode, value);
if (word && (value != word))
value = word;
else
value = gen_lowpart_common (word_mode,
force_reg (GET_MODE (value) != VOIDmode
? GET_MODE (value)
: word_mode, value));
}
while (bitsdone < bitsize)
{
unsigned HOST_WIDE_INT thissize;
rtx part, word;
unsigned HOST_WIDE_INT thispos;
unsigned HOST_WIDE_INT offset;
offset = (bitpos + bitsdone) / unit;
thispos = (bitpos + bitsdone) % unit;
/* THISSIZE must not overrun a word boundary. Otherwise,
store_fixed_bit_field will call us again, and we will mutually
recurse forever. */
thissize = MIN (bitsize - bitsdone, BITS_PER_WORD);
thissize = MIN (thissize, unit - thispos);
if (BYTES_BIG_ENDIAN)
{
int total_bits;
/* We must do an endian conversion exactly the same way as it is
done in extract_bit_field, so that the two calls to
extract_fixed_bit_field will have comparable arguments. */
if (!MEM_P (value) || GET_MODE (value) == BLKmode)
total_bits = BITS_PER_WORD;
else
total_bits = GET_MODE_BITSIZE (GET_MODE (value));
/* Fetch successively less significant portions. */
if (GET_CODE (value) == CONST_INT)
part = GEN_INT (((unsigned HOST_WIDE_INT) (INTVAL (value))
>> (bitsize - bitsdone - thissize))
& (((HOST_WIDE_INT) 1 << thissize) - 1));
else
/* The args are chosen so that the last part includes the
lsb. Give extract_bit_field the value it needs (with
endianness compensation) to fetch the piece we want. */
part = extract_fixed_bit_field (word_mode, value, 0, thissize,
total_bits - bitsize + bitsdone,
NULL_RTX, 1);
}
else
{
/* Fetch successively more significant portions. */
if (GET_CODE (value) == CONST_INT)
part = GEN_INT (((unsigned HOST_WIDE_INT) (INTVAL (value))
>> bitsdone)
& (((HOST_WIDE_INT) 1 << thissize) - 1));
else
part = extract_fixed_bit_field (word_mode, value, 0, thissize,
bitsdone, NULL_RTX, 1);
}
/* If OP0 is a register, then handle OFFSET here.
When handling multiword bitfields, extract_bit_field may pass
down a word_mode SUBREG of a larger REG for a bitfield that actually
crosses a word boundary. Thus, for a SUBREG, we must find
the current word starting from the base register. */
if (GET_CODE (op0) == SUBREG)
{
int word_offset = (SUBREG_BYTE (op0) / UNITS_PER_WORD) + offset;
word = operand_subword_force (SUBREG_REG (op0), word_offset,
GET_MODE (SUBREG_REG (op0)));
offset = 0;
}
else if (REG_P (op0))
{
word = operand_subword_force (op0, offset, GET_MODE (op0));
offset = 0;
}
else
word = op0;
/* OFFSET is in UNITs, and UNIT is in bits.
store_fixed_bit_field wants offset in bytes. */
store_fixed_bit_field (word, offset * unit / BITS_PER_UNIT, thissize,
thispos, part);
bitsdone += thissize;
}
}
/* A subroutine of extract_bit_field_1 that converts return value X
to either MODE or TMODE. MODE, TMODE and UNSIGNEDP are arguments
to extract_bit_field. */
static rtx
convert_extracted_bit_field (rtx x, enum machine_mode mode,
enum machine_mode tmode, bool unsignedp)
{
if (GET_MODE (x) == tmode || GET_MODE (x) == mode)
return x;
/* If the x mode is not a scalar integral, first convert to the
integer mode of that size and then access it as a floating-point
value via a SUBREG. */
if (!SCALAR_INT_MODE_P (tmode))
{
enum machine_mode smode;
smode = mode_for_size (GET_MODE_BITSIZE (tmode), MODE_INT, 0);
x = convert_to_mode (smode, x, unsignedp);
x = force_reg (smode, x);
return gen_lowpart (tmode, x);
}
return convert_to_mode (tmode, x, unsignedp);
}
/* A subroutine of extract_bit_field, with the same arguments.
If FALLBACK_P is true, fall back to extract_fixed_bit_field
if we can find no other means of implementing the operation.
if FALLBACK_P is false, return NULL instead. */
static rtx
extract_bit_field_1 (rtx str_rtx, unsigned HOST_WIDE_INT bitsize,
unsigned HOST_WIDE_INT bitnum, int unsignedp, rtx target,
enum machine_mode mode, enum machine_mode tmode,
bool fallback_p)
{
unsigned int unit
= (MEM_P (str_rtx)) ? BITS_PER_UNIT : BITS_PER_WORD;
unsigned HOST_WIDE_INT offset, bitpos;
rtx op0 = str_rtx;
enum machine_mode int_mode;
enum machine_mode ext_mode;
enum machine_mode mode1;
enum insn_code icode;
int byte_offset;
if (tmode == VOIDmode)
tmode = mode;
while (GET_CODE (op0) == SUBREG)
{
bitnum += SUBREG_BYTE (op0) * BITS_PER_UNIT;
op0 = SUBREG_REG (op0);
}
/* If we have an out-of-bounds access to a register, just return an
uninitialized register of the required mode. This can occur if the
source code contains an out-of-bounds access to a small array. */
if (REG_P (op0) && bitnum >= GET_MODE_BITSIZE (GET_MODE (op0)))
return gen_reg_rtx (tmode);
if (REG_P (op0)
&& mode == GET_MODE (op0)
&& bitnum == 0
&& bitsize == GET_MODE_BITSIZE (GET_MODE (op0)))
{
/* We're trying to extract a full register from itself. */
return op0;
}
/* See if we can get a better vector mode before extracting. */
if (VECTOR_MODE_P (GET_MODE (op0))
&& !MEM_P (op0)
&& GET_MODE_INNER (GET_MODE (op0)) != tmode)
{
enum machine_mode new_mode;
int nunits = GET_MODE_NUNITS (GET_MODE (op0));
if (GET_MODE_CLASS (tmode) == MODE_FLOAT)
new_mode = MIN_MODE_VECTOR_FLOAT;
else if (GET_MODE_CLASS (tmode) == MODE_FRACT)
new_mode = MIN_MODE_VECTOR_FRACT;
else if (GET_MODE_CLASS (tmode) == MODE_UFRACT)
new_mode = MIN_MODE_VECTOR_UFRACT;
else if (GET_MODE_CLASS (tmode) == MODE_ACCUM)
new_mode = MIN_MODE_VECTOR_ACCUM;
else if (GET_MODE_CLASS (tmode) == MODE_UACCUM)
new_mode = MIN_MODE_VECTOR_UACCUM;
else
new_mode = MIN_MODE_VECTOR_INT;
for (; new_mode != VOIDmode ; new_mode = GET_MODE_WIDER_MODE (new_mode))
if (GET_MODE_NUNITS (new_mode) == nunits
&& GET_MODE_SIZE (new_mode) == GET_MODE_SIZE (GET_MODE (op0))
&& targetm.vector_mode_supported_p (new_mode))
break;
if (new_mode != VOIDmode)
op0 = gen_lowpart (new_mode, op0);
}
/* Use vec_extract patterns for extracting parts of vectors whenever
available. */
if (VECTOR_MODE_P (GET_MODE (op0))
&& !MEM_P (op0)
&& (optab_handler (vec_extract_optab, GET_MODE (op0))->insn_code
!= CODE_FOR_nothing)
&& ((bitnum + bitsize - 1) / GET_MODE_BITSIZE (GET_MODE_INNER (GET_MODE (op0)))
== bitnum / GET_MODE_BITSIZE (GET_MODE_INNER (GET_MODE (op0)))))
{
enum machine_mode outermode = GET_MODE (op0);
enum machine_mode innermode = GET_MODE_INNER (outermode);
int icode = (int) optab_handler (vec_extract_optab, outermode)->insn_code;
unsigned HOST_WIDE_INT pos = bitnum / GET_MODE_BITSIZE (innermode);
rtx rtxpos = GEN_INT (pos);
rtx src = op0;
rtx dest = NULL, pat, seq;
enum machine_mode mode0 = insn_data[icode].operand[0].mode;
enum machine_mode mode1 = insn_data[icode].operand[1].mode;
enum machine_mode mode2 = insn_data[icode].operand[2].mode;
if (innermode == tmode || innermode == mode)
dest = target;
if (!dest)
dest = gen_reg_rtx (innermode);
start_sequence ();
if (! (*insn_data[icode].operand[0].predicate) (dest, mode0))
dest = copy_to_mode_reg (mode0, dest);
if (! (*insn_data[icode].operand[1].predicate) (src, mode1))
src = copy_to_mode_reg (mode1, src);
if (! (*insn_data[icode].operand[2].predicate) (rtxpos, mode2))
rtxpos = copy_to_mode_reg (mode1, rtxpos);
/* We could handle this, but we should always be called with a pseudo
for our targets and all insns should take them as outputs. */
gcc_assert ((*insn_data[icode].operand[0].predicate) (dest, mode0)
&& (*insn_data[icode].operand[1].predicate) (src, mode1)
&& (*insn_data[icode].operand[2].predicate) (rtxpos, mode2));
pat = GEN_FCN (icode) (dest, src, rtxpos);
seq = get_insns ();
end_sequence ();
if (pat)
{
emit_insn (seq);
emit_insn (pat);
if (mode0 != mode)
return gen_lowpart (tmode, dest);
return dest;
}
}
/* Make sure we are playing with integral modes. Pun with subregs
if we aren't. */
{
enum machine_mode imode = int_mode_for_mode (GET_MODE (op0));
if (imode != GET_MODE (op0))
{
if (MEM_P (op0))
op0 = adjust_address (op0, imode, 0);
else if (imode != BLKmode)
{
op0 = gen_lowpart (imode, op0);
/* If we got a SUBREG, force it into a register since we
aren't going to be able to do another SUBREG on it. */
if (GET_CODE (op0) == SUBREG)
op0 = force_reg (imode, op0);
}
else if (REG_P (op0))
{
rtx reg, subreg;
imode = smallest_mode_for_size (GET_MODE_BITSIZE (GET_MODE (op0)),
MODE_INT);
reg = gen_reg_rtx (imode);
subreg = gen_lowpart_SUBREG (GET_MODE (op0), reg);
emit_move_insn (subreg, op0);
op0 = reg;
bitnum += SUBREG_BYTE (subreg) * BITS_PER_UNIT;
}
else
{
rtx mem = assign_stack_temp (GET_MODE (op0),
GET_MODE_SIZE (GET_MODE (op0)), 0);
emit_move_insn (mem, op0);
op0 = adjust_address (mem, BLKmode, 0);
}
}
}
/* We may be accessing data outside the field, which means
we can alias adjacent data. */
if (MEM_P (op0))
{
op0 = shallow_copy_rtx (op0);
set_mem_alias_set (op0, 0);
set_mem_expr (op0, 0);
}
/* Extraction of a full-word or multi-word value from a structure
in a register or aligned memory can be done with just a SUBREG.
A subword value in the least significant part of a register
can also be extracted with a SUBREG. For this, we need the
byte offset of the value in op0. */
bitpos = bitnum % unit;
offset = bitnum / unit;
byte_offset = bitpos / BITS_PER_UNIT + offset * UNITS_PER_WORD;
/* If OP0 is a register, BITPOS must count within a word.
But as we have it, it counts within whatever size OP0 now has.
On a bigendian machine, these are not the same, so convert. */
if (BYTES_BIG_ENDIAN
&& !MEM_P (op0)
&& unit > GET_MODE_BITSIZE (GET_MODE (op0)))
bitpos += unit - GET_MODE_BITSIZE (GET_MODE (op0));
/* ??? We currently assume TARGET is at least as big as BITSIZE.
If that's wrong, the solution is to test for it and set TARGET to 0
if needed. */
/* Only scalar integer modes can be converted via subregs. There is an
additional problem for FP modes here in that they can have a precision
which is different from the size. mode_for_size uses precision, but
we want a mode based on the size, so we must avoid calling it for FP
modes. */
mode1 = (SCALAR_INT_MODE_P (tmode)
? mode_for_size (bitsize, GET_MODE_CLASS (tmode), 0)
: mode);
if (((bitsize >= BITS_PER_WORD && bitsize == GET_MODE_BITSIZE (mode)
&& bitpos % BITS_PER_WORD == 0)
|| (mode1 != BLKmode
/* ??? The big endian test here is wrong. This is correct
if the value is in a register, and if mode_for_size is not
the same mode as op0. This causes us to get unnecessarily
inefficient code from the Thumb port when -mbig-endian. */
&& (BYTES_BIG_ENDIAN
? bitpos + bitsize == BITS_PER_WORD
: bitpos == 0)))
&& ((!MEM_P (op0)
&& TRULY_NOOP_TRUNCATION (GET_MODE_BITSIZE (mode1),
GET_MODE_BITSIZE (GET_MODE (op0)))
&& GET_MODE_SIZE (mode1) != 0
&& byte_offset % GET_MODE_SIZE (mode1) == 0)
|| (MEM_P (op0)
&& (! SLOW_UNALIGNED_ACCESS (mode, MEM_ALIGN (op0))
|| (offset * BITS_PER_UNIT % bitsize == 0
&& MEM_ALIGN (op0) % bitsize == 0)))))
{
if (MEM_P (op0))
op0 = adjust_address (op0, mode1, offset);
else if (mode1 != GET_MODE (op0))
{
rtx sub = simplify_gen_subreg (mode1, op0, GET_MODE (op0),
byte_offset);
if (sub == NULL)
goto no_subreg_mode_swap;
op0 = sub;
}
if (mode1 != mode)
return convert_to_mode (tmode, op0, unsignedp);
return op0;
}
no_subreg_mode_swap:
/* Handle fields bigger than a word. */
if (bitsize > BITS_PER_WORD)
{
/* Here we transfer the words of the field
in the order least significant first.
This is because the most significant word is the one which may
be less than full. */
unsigned int nwords = (bitsize + (BITS_PER_WORD - 1)) / BITS_PER_WORD;
unsigned int i;
if (target == 0 || !REG_P (target))
target = gen_reg_rtx (mode);
/* Indicate for flow that the entire target reg is being set. */
emit_clobber (target);
for (i = 0; i < nwords; i++)
{
/* If I is 0, use the low-order word in both field and target;
if I is 1, use the next to lowest word; and so on. */
/* Word number in TARGET to use. */
unsigned int wordnum
= (WORDS_BIG_ENDIAN
? GET_MODE_SIZE (GET_MODE (target)) / UNITS_PER_WORD - i - 1
: i);
/* Offset from start of field in OP0. */
unsigned int bit_offset = (WORDS_BIG_ENDIAN
? MAX (0, ((int) bitsize - ((int) i + 1)
* (int) BITS_PER_WORD))
: (int) i * BITS_PER_WORD);
rtx target_part = operand_subword (target, wordnum, 1, VOIDmode);
rtx result_part
= extract_bit_field (op0, MIN (BITS_PER_WORD,
bitsize - i * BITS_PER_WORD),
bitnum + bit_offset, 1, target_part, mode,
word_mode);
gcc_assert (target_part);
if (result_part != target_part)
emit_move_insn (target_part, result_part);
}
if (unsignedp)
{
/* Unless we've filled TARGET, the upper regs in a multi-reg value
need to be zero'd out. */
if (GET_MODE_SIZE (GET_MODE (target)) > nwords * UNITS_PER_WORD)
{
unsigned int i, total_words;
total_words = GET_MODE_SIZE (GET_MODE (target)) / UNITS_PER_WORD;
for (i = nwords; i < total_words; i++)
emit_move_insn
(operand_subword (target,
WORDS_BIG_ENDIAN ? total_words - i - 1 : i,
1, VOIDmode),
const0_rtx);
}
return target;
}
/* Signed bit field: sign-extend with two arithmetic shifts. */
target = expand_shift (LSHIFT_EXPR, mode, target,
build_int_cst (NULL_TREE,
GET_MODE_BITSIZE (mode) - bitsize),
NULL_RTX, 0);
return expand_shift (RSHIFT_EXPR, mode, target,
build_int_cst (NULL_TREE,
GET_MODE_BITSIZE (mode) - bitsize),
NULL_RTX, 0);
}
/* From here on we know the desired field is smaller than a word. */
/* Check if there is a correspondingly-sized integer field, so we can
safely extract it as one size of integer, if necessary; then
truncate or extend to the size that is wanted; then use SUBREGs or
convert_to_mode to get one of the modes we really wanted. */
int_mode = int_mode_for_mode (tmode);
if (int_mode == BLKmode)
int_mode = int_mode_for_mode (mode);
/* Should probably push op0 out to memory and then do a load. */
gcc_assert (int_mode != BLKmode);
/* OFFSET is the number of words or bytes (UNIT says which)
from STR_RTX to the first word or byte containing part of the field. */
if (!MEM_P (op0))
{
if (offset != 0
|| GET_MODE_SIZE (GET_MODE (op0)) > UNITS_PER_WORD)
{
if (!REG_P (op0))
op0 = copy_to_reg (op0);
op0 = gen_rtx_SUBREG (mode_for_size (BITS_PER_WORD, MODE_INT, 0),
op0, (offset * UNITS_PER_WORD));
}
offset = 0;
}
/* Now OFFSET is nonzero only for memory operands. */
ext_mode = mode_for_extraction (unsignedp ? EP_extzv : EP_extv, 0);
icode = unsignedp ? CODE_FOR_extzv : CODE_FOR_extv;
if (ext_mode != MAX_MACHINE_MODE
&& bitsize > 0
&& GET_MODE_BITSIZE (ext_mode) >= bitsize
/* If op0 is a register, we need it in EXT_MODE to make it
acceptable to the format of ext(z)v. */
&& !(GET_CODE (op0) == SUBREG && GET_MODE (op0) != ext_mode)
&& !((REG_P (op0) || GET_CODE (op0) == SUBREG)
&& (bitsize + bitpos > GET_MODE_BITSIZE (ext_mode)))
&& check_predicate_volatile_ok (icode, 1, op0, GET_MODE (op0)))
{
unsigned HOST_WIDE_INT xbitpos = bitpos, xoffset = offset;
rtx bitsize_rtx, bitpos_rtx;
rtx last = get_last_insn ();
rtx xop0 = op0;
rtx xtarget = target;
rtx xspec_target = target;
rtx xspec_target_subreg = 0;
rtx pat;
/* If op0 is a register, we need it in EXT_MODE to make it
acceptable to the format of ext(z)v. */
if (REG_P (xop0) && GET_MODE (xop0) != ext_mode)
xop0 = gen_rtx_SUBREG (ext_mode, xop0, 0);
if (MEM_P (xop0))
/* Get ref to first byte containing part of the field. */
xop0 = adjust_address (xop0, byte_mode, xoffset);
/* On big-endian machines, we count bits from the most significant.
If the bit field insn does not, we must invert. */
if (BITS_BIG_ENDIAN != BYTES_BIG_ENDIAN)
xbitpos = unit - bitsize - xbitpos;
/* Now convert from counting within UNIT to counting in EXT_MODE. */
if (BITS_BIG_ENDIAN && !MEM_P (xop0))
xbitpos += GET_MODE_BITSIZE (ext_mode) - unit;
unit = GET_MODE_BITSIZE (ext_mode);
if (xtarget == 0)
xtarget = xspec_target = gen_reg_rtx (tmode);
if (GET_MODE (xtarget) != ext_mode)
{
/* Don't use LHS paradoxical subreg if explicit truncation is needed
between the mode of the extraction (word_mode) and the target
mode. Instead, create a temporary and use convert_move to set
the target. */
if (REG_P (xtarget)
&& TRULY_NOOP_TRUNCATION (GET_MODE_BITSIZE (GET_MODE (xtarget)),
GET_MODE_BITSIZE (ext_mode)))
{
xtarget = gen_lowpart (ext_mode, xtarget);
if (GET_MODE_SIZE (ext_mode)
> GET_MODE_SIZE (GET_MODE (xspec_target)))
xspec_target_subreg = xtarget;
}
else
xtarget = gen_reg_rtx (ext_mode);
}
/* If this machine's ext(z)v insists on a register target,
make sure we have one. */
if (!insn_data[(int) icode].operand[0].predicate (xtarget, ext_mode))
xtarget = gen_reg_rtx (ext_mode);
bitsize_rtx = GEN_INT (bitsize);
bitpos_rtx = GEN_INT (xbitpos);
pat = (unsignedp
? gen_extzv (xtarget, xop0, bitsize_rtx, bitpos_rtx)
: gen_extv (xtarget, xop0, bitsize_rtx, bitpos_rtx));
if (pat)
{
emit_insn (pat);
if (xtarget == xspec_target)
return xtarget;
if (xtarget == xspec_target_subreg)
return xspec_target;
return convert_extracted_bit_field (xtarget, mode, tmode, unsignedp);
}
delete_insns_since (last);
}
/* If OP0 is a memory, try copying it to a register and seeing if a
cheap register alternative is available. */
if (ext_mode != MAX_MACHINE_MODE && MEM_P (op0))
{
enum machine_mode bestmode;
/* Get the mode to use for inserting into this field. If
OP0 is BLKmode, get the smallest mode consistent with the
alignment. If OP0 is a non-BLKmode object that is no
wider than EXT_MODE, use its mode. Otherwise, use the
smallest mode containing the field. */
if (GET_MODE (op0) == BLKmode
|| (ext_mode != MAX_MACHINE_MODE
&& GET_MODE_SIZE (GET_MODE (op0)) > GET_MODE_SIZE (ext_mode)))
bestmode = get_best_mode (bitsize, bitnum, MEM_ALIGN (op0),
(ext_mode == MAX_MACHINE_MODE
? VOIDmode : ext_mode),
MEM_VOLATILE_P (op0));
else
bestmode = GET_MODE (op0);
if (bestmode != VOIDmode
&& !(SLOW_UNALIGNED_ACCESS (bestmode, MEM_ALIGN (op0))
&& GET_MODE_BITSIZE (bestmode) > MEM_ALIGN (op0)))
{
unsigned HOST_WIDE_INT xoffset, xbitpos;
/* Compute the offset as a multiple of this unit,
counting in bytes. */
unit = GET_MODE_BITSIZE (bestmode);
xoffset = (bitnum / unit) * GET_MODE_SIZE (bestmode);
xbitpos = bitnum % unit;
/* Make sure the register is big enough for the whole field. */
if (xoffset * BITS_PER_UNIT + unit
>= offset * BITS_PER_UNIT + bitsize)
{
rtx last, result, xop0;
last = get_last_insn ();
/* Fetch it to a register in that size. */
xop0 = adjust_address (op0, bestmode, xoffset);
xop0 = force_reg (bestmode, xop0);
result = extract_bit_field_1 (xop0, bitsize, xbitpos,
unsignedp, target,
mode, tmode, false);
if (result)
return result;
delete_insns_since (last);
}
}
}
if (!fallback_p)
return NULL;
target = extract_fixed_bit_field (int_mode, op0, offset, bitsize,
bitpos, target, unsignedp);
return convert_extracted_bit_field (target, mode, tmode, unsignedp);
}
/* Generate code to extract a byte-field from STR_RTX
containing BITSIZE bits, starting at BITNUM,
and put it in TARGET if possible (if TARGET is nonzero).
Regardless of TARGET, we return the rtx for where the value is placed.
STR_RTX is the structure containing the byte (a REG or MEM).
UNSIGNEDP is nonzero if this is an unsigned bit field.
MODE is the natural mode of the field value once extracted.
TMODE is the mode the caller would like the value to have;
but the value may be returned with type MODE instead.
If a TARGET is specified and we can store in it at no extra cost,
we do so, and return TARGET.
Otherwise, we return a REG of mode TMODE or MODE, with TMODE preferred
if they are equally easy. */
rtx
extract_bit_field (rtx str_rtx, unsigned HOST_WIDE_INT bitsize,
unsigned HOST_WIDE_INT bitnum, int unsignedp, rtx target,
enum machine_mode mode, enum machine_mode tmode)
{
return extract_bit_field_1 (str_rtx, bitsize, bitnum, unsignedp,
target, mode, tmode, true);
}
/* Extract a bit field using shifts and boolean operations
Returns an rtx to represent the value.
OP0 addresses a register (word) or memory (byte).
BITPOS says which bit within the word or byte the bit field starts in.
OFFSET says how many bytes farther the bit field starts;
it is 0 if OP0 is a register.
BITSIZE says how many bits long the bit field is.
(If OP0 is a register, it may be narrower than a full word,
but BITPOS still counts within a full word,
which is significant on bigendian machines.)
UNSIGNEDP is nonzero for an unsigned bit field (don't sign-extend value).
If TARGET is nonzero, attempts to store the value there
and return TARGET, but this is not guaranteed.
If TARGET is not used, create a pseudo-reg of mode TMODE for the value. */
static rtx
extract_fixed_bit_field (enum machine_mode tmode, rtx op0,
unsigned HOST_WIDE_INT offset,
unsigned HOST_WIDE_INT bitsize,
unsigned HOST_WIDE_INT bitpos, rtx target,
int unsignedp)
{
unsigned int total_bits = BITS_PER_WORD;
enum machine_mode mode;
if (GET_CODE (op0) == SUBREG || REG_P (op0))
{
/* Special treatment for a bit field split across two registers. */
if (bitsize + bitpos > BITS_PER_WORD)
return extract_split_bit_field (op0, bitsize, bitpos, unsignedp);
}
else
{
/* Get the proper mode to use for this field. We want a mode that
includes the entire field. If such a mode would be larger than
a word, we won't be doing the extraction the normal way. */
mode = get_best_mode (bitsize, bitpos + offset * BITS_PER_UNIT,
MEM_ALIGN (op0), word_mode, MEM_VOLATILE_P (op0));
if (mode == VOIDmode)
/* The only way this should occur is if the field spans word
boundaries. */
return extract_split_bit_field (op0, bitsize,
bitpos + offset * BITS_PER_UNIT,
unsignedp);
total_bits = GET_MODE_BITSIZE (mode);
/* Make sure bitpos is valid for the chosen mode. Adjust BITPOS to
be in the range 0 to total_bits-1, and put any excess bytes in
OFFSET. */
if (bitpos >= total_bits)
{
offset += (bitpos / total_bits) * (total_bits / BITS_PER_UNIT);
bitpos -= ((bitpos / total_bits) * (total_bits / BITS_PER_UNIT)
* BITS_PER_UNIT);
}
/* Get ref to an aligned byte, halfword, or word containing the field.
Adjust BITPOS to be position within a word,
and OFFSET to be the offset of that word.
Then alter OP0 to refer to that word. */
bitpos += (offset % (total_bits / BITS_PER_UNIT)) * BITS_PER_UNIT;
offset -= (offset % (total_bits / BITS_PER_UNIT));
op0 = adjust_address (op0, mode, offset);
}
mode = GET_MODE (op0);
if (BYTES_BIG_ENDIAN)
/* BITPOS is the distance between our msb and that of OP0.
Convert it to the distance from the lsb. */
bitpos = total_bits - bitsize - bitpos;
/* Now BITPOS is always the distance between the field's lsb and that of OP0.
We have reduced the big-endian case to the little-endian case. */
if (unsignedp)
{
if (bitpos)
{
/* If the field does not already start at the lsb,
shift it so it does. */
tree amount = build_int_cst (NULL_TREE, bitpos);
/* Maybe propagate the target for the shift. */
/* But not if we will return it--could confuse integrate.c. */
rtx subtarget = (target != 0 && REG_P (target) ? target : 0);
if (tmode != mode) subtarget = 0;
op0 = expand_shift (RSHIFT_EXPR, mode, op0, amount, subtarget, 1);
}
/* Convert the value to the desired mode. */
if (mode != tmode)
op0 = convert_to_mode (tmode, op0, 1);
/* Unless the msb of the field used to be the msb when we shifted,
mask out the upper bits. */
if (GET_MODE_BITSIZE (mode) != bitpos + bitsize)
return expand_binop (GET_MODE (op0), and_optab, op0,
mask_rtx (GET_MODE (op0), 0, bitsize, 0),
target, 1, OPTAB_LIB_WIDEN);
return op0;
}
/* To extract a signed bit-field, first shift its msb to the msb of the word,
then arithmetic-shift its lsb to the lsb of the word. */
op0 = force_reg (mode, op0);
if (mode != tmode)
target = 0;
/* Find the narrowest integer mode that contains the field. */
for (mode = GET_CLASS_NARROWEST_MODE (MODE_INT); mode != VOIDmode;
mode = GET_MODE_WIDER_MODE (mode))
if (GET_MODE_BITSIZE (mode) >= bitsize + bitpos)
{
op0 = convert_to_mode (mode, op0, 0);
break;
}
if (GET_MODE_BITSIZE (mode) != (bitsize + bitpos))
{
tree amount
= build_int_cst (NULL_TREE,
GET_MODE_BITSIZE (mode) - (bitsize + bitpos));
/* Maybe propagate the target for the shift. */
rtx subtarget = (target != 0 && REG_P (target) ? target : 0);
op0 = expand_shift (LSHIFT_EXPR, mode, op0, amount, subtarget, 1);
}
return expand_shift (RSHIFT_EXPR, mode, op0,
build_int_cst (NULL_TREE,
GET_MODE_BITSIZE (mode) - bitsize),
target, 0);
}
/* Return a constant integer (CONST_INT or CONST_DOUBLE) mask value
of mode MODE with BITSIZE ones followed by BITPOS zeros, or the
complement of that if COMPLEMENT. The mask is truncated if
necessary to the width of mode MODE. The mask is zero-extended if
BITSIZE+BITPOS is too small for MODE. */
static rtx
mask_rtx (enum machine_mode mode, int bitpos, int bitsize, int complement)
{
HOST_WIDE_INT masklow, maskhigh;
if (bitsize == 0)
masklow = 0;
else if (bitpos < HOST_BITS_PER_WIDE_INT)
masklow = (HOST_WIDE_INT) -1 << bitpos;
else
masklow = 0;
if (bitpos + bitsize < HOST_BITS_PER_WIDE_INT)
masklow &= ((unsigned HOST_WIDE_INT) -1
>> (HOST_BITS_PER_WIDE_INT - bitpos - bitsize));
if (bitpos <= HOST_BITS_PER_WIDE_INT)
maskhigh = -1;
else
maskhigh = (HOST_WIDE_INT) -1 << (bitpos - HOST_BITS_PER_WIDE_INT);
if (bitsize == 0)
maskhigh = 0;
else if (bitpos + bitsize > HOST_BITS_PER_WIDE_INT)
maskhigh &= ((unsigned HOST_WIDE_INT) -1
>> (2 * HOST_BITS_PER_WIDE_INT - bitpos - bitsize));
else
maskhigh = 0;
if (complement)
{
maskhigh = ~maskhigh;
masklow = ~masklow;
}
return immed_double_const (masklow, maskhigh, mode);
}
/* Return a constant integer (CONST_INT or CONST_DOUBLE) rtx with the value
VALUE truncated to BITSIZE bits and then shifted left BITPOS bits. */
static rtx
lshift_value (enum machine_mode mode, rtx value, int bitpos, int bitsize)
{
unsigned HOST_WIDE_INT v = INTVAL (value);
HOST_WIDE_INT low, high;
if (bitsize < HOST_BITS_PER_WIDE_INT)
v &= ~((HOST_WIDE_INT) -1 << bitsize);
if (bitpos < HOST_BITS_PER_WIDE_INT)
{
low = v << bitpos;
high = (bitpos > 0 ? (v >> (HOST_BITS_PER_WIDE_INT - bitpos)) : 0);
}
else
{
low = 0;
high = v << (bitpos - HOST_BITS_PER_WIDE_INT);
}
return immed_double_const (low, high, mode);
}
/* Extract a bit field that is split across two words
and return an RTX for the result.
OP0 is the REG, SUBREG or MEM rtx for the first of the two words.
BITSIZE is the field width; BITPOS, position of its first bit, in the word.
UNSIGNEDP is 1 if should zero-extend the contents; else sign-extend. */
static rtx
extract_split_bit_field (rtx op0, unsigned HOST_WIDE_INT bitsize,
unsigned HOST_WIDE_INT bitpos, int unsignedp)
{
unsigned int unit;
unsigned int bitsdone = 0;
rtx result = NULL_RTX;
int first = 1;
/* Make sure UNIT isn't larger than BITS_PER_WORD, we can only handle that
much at a time. */
if (REG_P (op0) || GET_CODE (op0) == SUBREG)
unit = BITS_PER_WORD;
else
unit = MIN (MEM_ALIGN (op0), BITS_PER_WORD);
while (bitsdone < bitsize)
{
unsigned HOST_WIDE_INT thissize;
rtx part, word;
unsigned HOST_WIDE_INT thispos;
unsigned HOST_WIDE_INT offset;
offset = (bitpos + bitsdone) / unit;
thispos = (bitpos + bitsdone) % unit;
/* THISSIZE must not overrun a word boundary. Otherwise,
extract_fixed_bit_field will call us again, and we will mutually
recurse forever. */
thissize = MIN (bitsize - bitsdone, BITS_PER_WORD);
thissize = MIN (thissize, unit - thispos);
/* If OP0 is a register, then handle OFFSET here.
When handling multiword bitfields, extract_bit_field may pass
down a word_mode SUBREG of a larger REG for a bitfield that actually
crosses a word boundary. Thus, for a SUBREG, we must find
the current word starting from the base register. */
if (GET_CODE (op0) == SUBREG)
{
int word_offset = (SUBREG_BYTE (op0) / UNITS_PER_WORD) + offset;
word = operand_subword_force (SUBREG_REG (op0), word_offset,
GET_MODE (SUBREG_REG (op0)));
offset = 0;
}
else if (REG_P (op0))
{
word = operand_subword_force (op0, offset, GET_MODE (op0));
offset = 0;
}
else
word = op0;
/* Extract the parts in bit-counting order,
whose meaning is determined by BYTES_PER_UNIT.
OFFSET is in UNITs, and UNIT is in bits.
extract_fixed_bit_field wants offset in bytes. */
part = extract_fixed_bit_field (word_mode, word,
offset * unit / BITS_PER_UNIT,
thissize, thispos, 0, 1);
bitsdone += thissize;
/* Shift this part into place for the result. */
if (BYTES_BIG_ENDIAN)
{
if (bitsize != bitsdone)
part = expand_shift (LSHIFT_EXPR, word_mode, part,
build_int_cst (NULL_TREE, bitsize - bitsdone),
0, 1);
}
else
{
if (bitsdone != thissize)
part = expand_shift (LSHIFT_EXPR, word_mode, part,
build_int_cst (NULL_TREE,
bitsdone - thissize), 0, 1);
}
if (first)
result = part;
else
/* Combine the parts with bitwise or. This works
because we extracted each part as an unsigned bit field. */
result = expand_binop (word_mode, ior_optab, part, result, NULL_RTX, 1,
OPTAB_LIB_WIDEN);
first = 0;
}
/* Unsigned bit field: we are done. */
if (unsignedp)
return result;
/* Signed bit field: sign-extend with two arithmetic shifts. */
result = expand_shift (LSHIFT_EXPR, word_mode, result,
build_int_cst (NULL_TREE, BITS_PER_WORD - bitsize),
NULL_RTX, 0);
return expand_shift (RSHIFT_EXPR, word_mode, result,
build_int_cst (NULL_TREE, BITS_PER_WORD - bitsize),
NULL_RTX, 0);
}
/* Try to read the low bits of SRC as an rvalue of mode MODE, preserving
the bit pattern. SRC_MODE is the mode of SRC; if this is smaller than
MODE, fill the upper bits with zeros. Fail if the layout of either
mode is unknown (as for CC modes) or if the extraction would involve
unprofitable mode punning. Return the value on success, otherwise
return null.
This is different from gen_lowpart* in these respects:
- the returned value must always be considered an rvalue
- when MODE is wider than SRC_MODE, the extraction involves
a zero extension
- when MODE is smaller than SRC_MODE, the extraction involves
a truncation (and is thus subject to TRULY_NOOP_TRUNCATION).
In other words, this routine performs a computation, whereas the
gen_lowpart* routines are conceptually lvalue or rvalue subreg
operations. */
rtx
extract_low_bits (enum machine_mode mode, enum machine_mode src_mode, rtx src)
{
enum machine_mode int_mode, src_int_mode;
if (mode == src_mode)
return src;
if (CONSTANT_P (src))
{
/* simplify_gen_subreg can't be used here, as if simplify_subreg
fails, it will happily create (subreg (symbol_ref)) or similar
invalid SUBREGs. */
unsigned int byte = subreg_lowpart_offset (mode, src_mode);
rtx ret = simplify_subreg (mode, src, src_mode, byte);
if (ret)
return ret;
if (GET_MODE (src) == VOIDmode
|| !validate_subreg (mode, src_mode, src, byte))
return NULL_RTX;
src = force_reg (GET_MODE (src), src);
return gen_rtx_SUBREG (mode, src, byte);
}
if (GET_MODE_CLASS (mode) == MODE_CC || GET_MODE_CLASS (src_mode) == MODE_CC)
return NULL_RTX;
if (GET_MODE_BITSIZE (mode) == GET_MODE_BITSIZE (src_mode)
&& MODES_TIEABLE_P (mode, src_mode))
{
rtx x = gen_lowpart_common (mode, src);
if (x)
return x;
}
src_int_mode = int_mode_for_mode (src_mode);
int_mode = int_mode_for_mode (mode);
if (src_int_mode == BLKmode || int_mode == BLKmode)
return NULL_RTX;
if (!MODES_TIEABLE_P (src_int_mode, src_mode))
return NULL_RTX;
if (!MODES_TIEABLE_P (int_mode, mode))
return NULL_RTX;
src = gen_lowpart (src_int_mode, src);
src = convert_modes (int_mode, src_int_mode, src, true);
src = gen_lowpart (mode, src);
return src;
}
/* Add INC into TARGET. */
void
expand_inc (rtx target, rtx inc)
{
rtx value = expand_binop (GET_MODE (target), add_optab,
target, inc,
target, 0, OPTAB_LIB_WIDEN);
if (value != target)
emit_move_insn (target, value);
}
/* Subtract DEC from TARGET. */
void
expand_dec (rtx target, rtx dec)
{
rtx value = expand_binop (GET_MODE (target), sub_optab,
target, dec,
target, 0, OPTAB_LIB_WIDEN);
if (value != target)
emit_move_insn (target, value);
}
/* Output a shift instruction for expression code CODE,
with SHIFTED being the rtx for the value to shift,
and AMOUNT the tree for the amount to shift by.
Store the result in the rtx TARGET, if that is convenient.
If UNSIGNEDP is nonzero, do a logical shift; otherwise, arithmetic.
Return the rtx for where the value is. */
rtx
expand_shift (enum tree_code code, enum machine_mode mode, rtx shifted,
tree amount, rtx target, int unsignedp)
{
rtx op1, temp = 0;
int left = (code == LSHIFT_EXPR || code == LROTATE_EXPR);
int rotate = (code == LROTATE_EXPR || code == RROTATE_EXPR);
optab lshift_optab = ashl_optab;
optab rshift_arith_optab = ashr_optab;
optab rshift_uns_optab = lshr_optab;
optab lrotate_optab = rotl_optab;
optab rrotate_optab = rotr_optab;
enum machine_mode op1_mode;
int attempt;
bool speed = optimize_insn_for_speed_p ();
op1 = expand_normal (amount);
op1_mode = GET_MODE (op1);
/* Determine whether the shift/rotate amount is a vector, or scalar. If the
shift amount is a vector, use the vector/vector shift patterns. */
if (VECTOR_MODE_P (mode) && VECTOR_MODE_P (op1_mode))
{
lshift_optab = vashl_optab;
rshift_arith_optab = vashr_optab;
rshift_uns_optab = vlshr_optab;
lrotate_optab = vrotl_optab;
rrotate_optab = vrotr_optab;
}
/* Previously detected shift-counts computed by NEGATE_EXPR
and shifted in the other direction; but that does not work
on all machines. */
if (SHIFT_COUNT_TRUNCATED)
{
if (GET_CODE (op1) == CONST_INT
&& ((unsigned HOST_WIDE_INT) INTVAL (op1) >=
(unsigned HOST_WIDE_INT) GET_MODE_BITSIZE (mode)))
op1 = GEN_INT ((unsigned HOST_WIDE_INT) INTVAL (op1)
% GET_MODE_BITSIZE (mode));
else if (GET_CODE (op1) == SUBREG
&& subreg_lowpart_p (op1)
&& INTEGRAL_MODE_P (GET_MODE (SUBREG_REG (op1))))
op1 = SUBREG_REG (op1);
}
if (op1 == const0_rtx)
return shifted;
/* Check whether its cheaper to implement a left shift by a constant
bit count by a sequence of additions. */
if (code == LSHIFT_EXPR
&& GET_CODE (op1) == CONST_INT
&& INTVAL (op1) > 0
&& INTVAL (op1) < GET_MODE_BITSIZE (mode)
&& INTVAL (op1) < MAX_BITS_PER_WORD
&& shift_cost[speed][mode][INTVAL (op1)] > INTVAL (op1) * add_cost[speed][mode]
&& shift_cost[speed][mode][INTVAL (op1)] != MAX_COST)
{
int i;
for (i = 0; i < INTVAL (op1); i++)
{
temp = force_reg (mode, shifted);
shifted = expand_binop (mode, add_optab, temp, temp, NULL_RTX,
unsignedp, OPTAB_LIB_WIDEN);
}
return shifted;
}
for (attempt = 0; temp == 0 && attempt < 3; attempt++)
{
enum optab_methods methods;
if (attempt == 0)
methods = OPTAB_DIRECT;
else if (attempt == 1)
methods = OPTAB_WIDEN;
else
methods = OPTAB_LIB_WIDEN;
if (rotate)
{
/* Widening does not work for rotation. */
if (methods == OPTAB_WIDEN)
continue;
else if (methods == OPTAB_LIB_WIDEN)
{
/* If we have been unable to open-code this by a rotation,
do it as the IOR of two shifts. I.e., to rotate A
by N bits, compute (A << N) | ((unsigned) A >> (C - N))
where C is the bitsize of A.
It is theoretically possible that the target machine might
not be able to perform either shift and hence we would
be making two libcalls rather than just the one for the
shift (similarly if IOR could not be done). We will allow
this extremely unlikely lossage to avoid complicating the
code below. */
rtx subtarget = target == shifted ? 0 : target;
tree new_amount, other_amount;
rtx temp1;
tree type = TREE_TYPE (amount);
if (GET_MODE (op1) != TYPE_MODE (type)
&& GET_MODE (op1) != VOIDmode)
op1 = convert_to_mode (TYPE_MODE (type), op1, 1);
new_amount = make_tree (type, op1);
other_amount
= fold_build2 (MINUS_EXPR, type,
build_int_cst (type, GET_MODE_BITSIZE (mode)),
new_amount);
shifted = force_reg (mode, shifted);
temp = expand_shift (left ? LSHIFT_EXPR : RSHIFT_EXPR,
mode, shifted, new_amount, 0, 1);
temp1 = expand_shift (left ? RSHIFT_EXPR : LSHIFT_EXPR,
mode, shifted, other_amount, subtarget, 1);
return expand_binop (mode, ior_optab, temp, temp1, target,
unsignedp, methods);
}
temp = expand_binop (mode,
left ? lrotate_optab : rrotate_optab,
shifted, op1, target, unsignedp, methods);
}
else if (unsignedp)
temp = expand_binop (mode,
left ? lshift_optab : rshift_uns_optab,
shifted, op1, target, unsignedp, methods);
/* Do arithmetic shifts.
Also, if we are going to widen the operand, we can just as well
use an arithmetic right-shift instead of a logical one. */
if (temp == 0 && ! rotate
&& (! unsignedp || (! left && methods == OPTAB_WIDEN)))
{
enum optab_methods methods1 = methods;
/* If trying to widen a log shift to an arithmetic shift,
don't accept an arithmetic shift of the same size. */
if (unsignedp)
methods1 = OPTAB_MUST_WIDEN;
/* Arithmetic shift */
temp = expand_binop (mode,
left ? lshift_optab : rshift_arith_optab,
shifted, op1, target, unsignedp, methods1);
}
/* We used to try extzv here for logical right shifts, but that was
only useful for one machine, the VAX, and caused poor code
generation there for lshrdi3, so the code was deleted and a
define_expand for lshrsi3 was added to vax.md. */
}
gcc_assert (temp);
return temp;
}
enum alg_code {
alg_unknown,
alg_zero,
alg_m, alg_shift,
alg_add_t_m2,
alg_sub_t_m2,
alg_add_factor,
alg_sub_factor,
alg_add_t2_m,
alg_sub_t2_m,
alg_impossible
};
/* This structure holds the "cost" of a multiply sequence. The
"cost" field holds the total rtx_cost of every operator in the
synthetic multiplication sequence, hence cost(a op b) is defined
as rtx_cost(op) + cost(a) + cost(b), where cost(leaf) is zero.
The "latency" field holds the minimum possible latency of the
synthetic multiply, on a hypothetical infinitely parallel CPU.
This is the critical path, or the maximum height, of the expression
tree which is the sum of rtx_costs on the most expensive path from
any leaf to the root. Hence latency(a op b) is defined as zero for
leaves and rtx_cost(op) + max(latency(a), latency(b)) otherwise. */
struct mult_cost {
short cost; /* Total rtx_cost of the multiplication sequence. */
short latency; /* The latency of the multiplication sequence. */
};
/* This macro is used to compare a pointer to a mult_cost against an
single integer "rtx_cost" value. This is equivalent to the macro
CHEAPER_MULT_COST(X,Z) where Z = {Y,Y}. */
#define MULT_COST_LESS(X,Y) ((X)->cost < (Y) \
|| ((X)->cost == (Y) && (X)->latency < (Y)))
/* This macro is used to compare two pointers to mult_costs against
each other. The macro returns true if X is cheaper than Y.
Currently, the cheaper of two mult_costs is the one with the
lower "cost". If "cost"s are tied, the lower latency is cheaper. */
#define CHEAPER_MULT_COST(X,Y) ((X)->cost < (Y)->cost \
|| ((X)->cost == (Y)->cost \
&& (X)->latency < (Y)->latency))
/* This structure records a sequence of operations.
`ops' is the number of operations recorded.
`cost' is their total cost.
The operations are stored in `op' and the corresponding
logarithms of the integer coefficients in `log'.
These are the operations:
alg_zero total := 0;
alg_m total := multiplicand;
alg_shift total := total * coeff
alg_add_t_m2 total := total + multiplicand * coeff;
alg_sub_t_m2 total := total - multiplicand * coeff;
alg_add_factor total := total * coeff + total;
alg_sub_factor total := total * coeff - total;
alg_add_t2_m total := total * coeff + multiplicand;
alg_sub_t2_m total := total * coeff - multiplicand;
The first operand must be either alg_zero or alg_m. */
struct algorithm
{
struct mult_cost cost;
short ops;
/* The size of the OP and LOG fields are not directly related to the
word size, but the worst-case algorithms will be if we have few
consecutive ones or zeros, i.e., a multiplicand like 10101010101...
In that case we will generate shift-by-2, add, shift-by-2, add,...,
in total wordsize operations. */
enum alg_code op[MAX_BITS_PER_WORD];
char log[MAX_BITS_PER_WORD];
};
/* The entry for our multiplication cache/hash table. */
struct alg_hash_entry {
/* The number we are multiplying by. */
unsigned HOST_WIDE_INT t;
/* The mode in which we are multiplying something by T. */
enum machine_mode mode;
/* The best multiplication algorithm for t. */
enum alg_code alg;
/* The cost of multiplication if ALG_CODE is not alg_impossible.
Otherwise, the cost within which multiplication by T is
impossible. */
struct mult_cost cost;
/* OPtimized for speed? */
bool speed;
};
/* The number of cache/hash entries. */
#if HOST_BITS_PER_WIDE_INT == 64
#define NUM_ALG_HASH_ENTRIES 1031
#else
#define NUM_ALG_HASH_ENTRIES 307
#endif
/* Each entry of ALG_HASH caches alg_code for some integer. This is
actually a hash table. If we have a collision, that the older
entry is kicked out. */
static struct alg_hash_entry alg_hash[NUM_ALG_HASH_ENTRIES];
/* Indicates the type of fixup needed after a constant multiplication.
BASIC_VARIANT means no fixup is needed, NEGATE_VARIANT means that
the result should be negated, and ADD_VARIANT means that the
multiplicand should be added to the result. */
enum mult_variant {basic_variant, negate_variant, add_variant};
static void synth_mult (struct algorithm *, unsigned HOST_WIDE_INT,
const struct mult_cost *, enum machine_mode mode);
static bool choose_mult_variant (enum machine_mode, HOST_WIDE_INT,
struct algorithm *, enum mult_variant *, int);
static rtx expand_mult_const (enum machine_mode, rtx, HOST_WIDE_INT, rtx,
const struct algorithm *, enum mult_variant);
static unsigned HOST_WIDE_INT choose_multiplier (unsigned HOST_WIDE_INT, int,
int, rtx *, int *, int *);
static unsigned HOST_WIDE_INT invert_mod2n (unsigned HOST_WIDE_INT, int);
static rtx extract_high_half (enum machine_mode, rtx);
static rtx expand_mult_highpart (enum machine_mode, rtx, rtx, rtx, int, int);
static rtx expand_mult_highpart_optab (enum machine_mode, rtx, rtx, rtx,
int, int);
/* Compute and return the best algorithm for multiplying by T.
The algorithm must cost less than cost_limit
If retval.cost >= COST_LIMIT, no algorithm was found and all
other field of the returned struct are undefined.
MODE is the machine mode of the multiplication. */
static void
synth_mult (struct algorithm *alg_out, unsigned HOST_WIDE_INT t,
const struct mult_cost *cost_limit, enum machine_mode mode)
{
int m;
struct algorithm *alg_in, *best_alg;
struct mult_cost best_cost;
struct mult_cost new_limit;
int op_cost, op_latency;
unsigned HOST_WIDE_INT q;
int maxm = MIN (BITS_PER_WORD, GET_MODE_BITSIZE (mode));
int hash_index;
bool cache_hit = false;
enum alg_code cache_alg = alg_zero;
bool speed = optimize_insn_for_speed_p ();
/* Indicate that no algorithm is yet found. If no algorithm
is found, this value will be returned and indicate failure. */
alg_out->cost.cost = cost_limit->cost + 1;
alg_out->cost.latency = cost_limit->latency + 1;
if (cost_limit->cost < 0
|| (cost_limit->cost == 0 && cost_limit->latency <= 0))
return;
/* Restrict the bits of "t" to the multiplication's mode. */
t &= GET_MODE_MASK (mode);
/* t == 1 can be done in zero cost. */
if (t == 1)
{
alg_out->ops = 1;
alg_out->cost.cost = 0;
alg_out->cost.latency = 0;
alg_out->op[0] = alg_m;
return;
}
/* t == 0 sometimes has a cost. If it does and it exceeds our limit,
fail now. */
if (t == 0)
{
if (MULT_COST_LESS (cost_limit, zero_cost[speed]))
return;
else
{
alg_out->ops = 1;
alg_out->cost.cost = zero_cost[speed];
alg_out->cost.latency = zero_cost[speed];
alg_out->op[0] = alg_zero;
return;
}
}
/* We'll be needing a couple extra algorithm structures now. */
alg_in = XALLOCA (struct algorithm);
best_alg = XALLOCA (struct algorithm);
best_cost = *cost_limit;
/* Compute the hash index. */
hash_index = (t ^ (unsigned int) mode ^ (speed * 256)) % NUM_ALG_HASH_ENTRIES;
/* See if we already know what to do for T. */
if (alg_hash[hash_index].t == t
&& alg_hash[hash_index].mode == mode
&& alg_hash[hash_index].mode == mode
&& alg_hash[hash_index].speed == speed
&& alg_hash[hash_index].alg != alg_unknown)
{
cache_alg = alg_hash[hash_index].alg;
if (cache_alg == alg_impossible)
{
/* The cache tells us that it's impossible to synthesize
multiplication by T within alg_hash[hash_index].cost. */
if (!CHEAPER_MULT_COST (&alg_hash[hash_index].cost, cost_limit))
/* COST_LIMIT is at least as restrictive as the one
recorded in the hash table, in which case we have no
hope of synthesizing a multiplication. Just
return. */
return;
/* If we get here, COST_LIMIT is less restrictive than the
one recorded in the hash table, so we may be able to
synthesize a multiplication. Proceed as if we didn't
have the cache entry. */
}
else
{
if (CHEAPER_MULT_COST (cost_limit, &alg_hash[hash_index].cost))
/* The cached algorithm shows that this multiplication
requires more cost than COST_LIMIT. Just return. This
way, we don't clobber this cache entry with
alg_impossible but retain useful information. */
return;
cache_hit = true;
switch (cache_alg)
{
case alg_shift:
goto do_alg_shift;
case alg_add_t_m2:
case alg_sub_t_m2:
goto do_alg_addsub_t_m2;
case alg_add_factor:
case alg_sub_factor:
goto do_alg_addsub_factor;
case alg_add_t2_m:
goto do_alg_add_t2_m;
case alg_sub_t2_m:
goto do_alg_sub_t2_m;
default:
gcc_unreachable ();
}
}
}
/* If we have a group of zero bits at the low-order part of T, try
multiplying by the remaining bits and then doing a shift. */
if ((t & 1) == 0)
{
do_alg_shift:
m = floor_log2 (t & -t); /* m = number of low zero bits */
if (m < maxm)
{
q = t >> m;
/* The function expand_shift will choose between a shift and
a sequence of additions, so the observed cost is given as
MIN (m * add_cost[speed][mode], shift_cost[speed][mode][m]). */
op_cost = m * add_cost[speed][mode];
if (shift_cost[speed][mode][m] < op_cost)
op_cost = shift_cost[speed][mode][m];
new_limit.cost = best_cost.cost - op_cost;
new_limit.latency = best_cost.latency - op_cost;
synth_mult (alg_in, q, &new_limit, mode);
alg_in->cost.cost += op_cost;
alg_in->cost.latency += op_cost;
if (CHEAPER_MULT_COST (&alg_in->cost, &best_cost))
{
struct algorithm *x;
best_cost = alg_in->cost;
x = alg_in, alg_in = best_alg, best_alg = x;
best_alg->log[best_alg->ops] = m;
best_alg->op[best_alg->ops] = alg_shift;
}
}
if (cache_hit)
goto done;
}
/* If we have an odd number, add or subtract one. */
if ((t & 1) != 0)
{
unsigned HOST_WIDE_INT w;
do_alg_addsub_t_m2:
for (w = 1; (w & t) != 0; w <<= 1)
;
/* If T was -1, then W will be zero after the loop. This is another
case where T ends with ...111. Handling this with (T + 1) and
subtract 1 produces slightly better code and results in algorithm
selection much faster than treating it like the ...0111 case
below. */
if (w == 0
|| (w > 2
/* Reject the case where t is 3.
Thus we prefer addition in that case. */
&& t != 3))
{
/* T ends with ...111. Multiply by (T + 1) and subtract 1. */
op_cost = add_cost[speed][mode];
new_limit.cost = best_cost.cost - op_cost;
new_limit.latency = best_cost.latency - op_cost;
synth_mult (alg_in, t + 1, &new_limit, mode);
alg_in->cost.cost += op_cost;
alg_in->cost.latency += op_cost;
if (CHEAPER_MULT_COST (&alg_in->cost, &best_cost))
{
struct algorithm *x;
best_cost = alg_in->cost;
x = alg_in, alg_in = best_alg, best_alg = x;
best_alg->log[best_alg->ops] = 0;
best_alg->op[best_alg->ops] = alg_sub_t_m2;
}
}
else
{
/* T ends with ...01 or ...011. Multiply by (T - 1) and add 1. */
op_cost = add_cost[speed][mode];
new_limit.cost = best_cost.cost - op_cost;
new_limit.latency = best_cost.latency - op_cost;
synth_mult (alg_in, t - 1, &new_limit, mode);
alg_in->cost.cost += op_cost;
alg_in->cost.latency += op_cost;
if (CHEAPER_MULT_COST (&alg_in->cost, &best_cost))
{
struct algorithm *x;
best_cost = alg_in->cost;
x = alg_in, alg_in = best_alg, best_alg = x;
best_alg->log[best_alg->ops] = 0;
best_alg->op[best_alg->ops] = alg_add_t_m2;
}
}
if (cache_hit)
goto done;
}
/* Look for factors of t of the form
t = q(2**m +- 1), 2 <= m <= floor(log2(t - 1)).
If we find such a factor, we can multiply by t using an algorithm that
multiplies by q, shift the result by m and add/subtract it to itself.
We search for large factors first and loop down, even if large factors
are less probable than small; if we find a large factor we will find a
good sequence quickly, and therefore be able to prune (by decreasing
COST_LIMIT) the search. */
do_alg_addsub_factor:
for (m = floor_log2 (t - 1); m >= 2; m--)
{
unsigned HOST_WIDE_INT d;
d = ((unsigned HOST_WIDE_INT) 1 << m) + 1;
if (t % d == 0 && t > d && m < maxm
&& (!cache_hit || cache_alg == alg_add_factor))
{
/* If the target has a cheap shift-and-add instruction use
that in preference to a shift insn followed by an add insn.
Assume that the shift-and-add is "atomic" with a latency
equal to its cost, otherwise assume that on superscalar
hardware the shift may be executed concurrently with the
earlier steps in the algorithm. */
op_cost = add_cost[speed][mode] + shift_cost[speed][mode][m];
if (shiftadd_cost[speed][mode][m] < op_cost)
{
op_cost = shiftadd_cost[speed][mode][m];
op_latency = op_cost;
}
else
op_latency = add_cost[speed][mode];
new_limit.cost = best_cost.cost - op_cost;
new_limit.latency = best_cost.latency - op_latency;
synth_mult (alg_in, t / d, &new_limit, mode);
alg_in->cost.cost += op_cost;
alg_in->cost.latency += op_latency;
if (alg_in->cost.latency < op_cost)
alg_in->cost.latency = op_cost;
if (CHEAPER_MULT_COST (&alg_in->cost, &best_cost))
{
struct algorithm *x;
best_cost = alg_in->cost;
x = alg_in, alg_in = best_alg, best_alg = x;
best_alg->log[best_alg->ops] = m;
best_alg->op[best_alg->ops] = alg_add_factor;
}
/* Other factors will have been taken care of in the recursion. */
break;
}
d = ((unsigned HOST_WIDE_INT) 1 << m) - 1;
if (t % d == 0 && t > d && m < maxm
&& (!cache_hit || cache_alg == alg_sub_factor))
{
/* If the target has a cheap shift-and-subtract insn use
that in preference to a shift insn followed by a sub insn.
Assume that the shift-and-sub is "atomic" with a latency
equal to it's cost, otherwise assume that on superscalar
hardware the shift may be executed concurrently with the
earlier steps in the algorithm. */
op_cost = add_cost[speed][mode] + shift_cost[speed][mode][m];
if (shiftsub_cost[speed][mode][m] < op_cost)
{
op_cost = shiftsub_cost[speed][mode][m];
op_latency = op_cost;
}
else
op_latency = add_cost[speed][mode];
new_limit.cost = best_cost.cost - op_cost;
new_limit.latency = best_cost.latency - op_latency;
synth_mult (alg_in, t / d, &new_limit, mode);
alg_in->cost.cost += op_cost;
alg_in->cost.latency += op_latency;
if (alg_in->cost.latency < op_cost)
alg_in->cost.latency = op_cost;
if (CHEAPER_MULT_COST (&alg_in->cost, &best_cost))
{
struct algorithm *x;
best_cost = alg_in->cost;
x = alg_in, alg_in = best_alg, best_alg = x;
best_alg->log[best_alg->ops] = m;
best_alg->op[best_alg->ops] = alg_sub_factor;
}
break;
}
}
if (cache_hit)
goto done;
/* Try shift-and-add (load effective address) instructions,
i.e. do a*3, a*5, a*9. */
if ((t & 1) != 0)
{
do_alg_add_t2_m:
q = t - 1;
q = q & -q;
m = exact_log2 (q);
if (m >= 0 && m < maxm)
{
op_cost = shiftadd_cost[speed][mode][m];
new_limit.cost = best_cost.cost - op_cost;
new_limit.latency = best_cost.latency - op_cost;